E N E R G Y   F O R   O U R   W O R L D


Prof. dr Nenad Djajic
 
 

In the period 1960/90 the world's energy requirement has risen considerably.In 1960 the world used 3,3 Gtoe of energy and in 1990 used 8,7 Gtoe,or an increase of 164 % with average increase of 3,3 % p.a.Two main forces driving energy demand have been :population growth and economic development.Thus between 1960 and 1990 world population rose nearly 2,3 bilion,within the developing countries accounted for 87 % of this growth,increasing their share of world population from 68 % to 76 % in 1990(fig.1).
 
 

BILIONS


 
 

Figure. 1 POPULATION





But there are wide divergences in energy use.By far the largest energy consumers are industrialised countries-OECD and Central Eastern Europe.In 1990 these countries accounted for some 66 % of the world's energy consumption.Only one third of energy was consumed by the developing countries, as shown on fig.2. Also, energy use per capita is even more varied. At present the majority of the world' population uses less than 1,2 toe of energy per head(indeed many use less than a third of this);the developed countries use more than 7 toe per capita.

GToe

Figure 2 Energu requirement







We can see that the relative increase of wealth in the developing countries( the developing countrie's share of world economic output has grown from 26 % in 1960 to 34 % in 1990) has gone more into supporting population increase rather than into increasing the economic prosperity of individuals.The economic wealth per capita of the rich countries in 1960. was 7,2 times greater than that in the poor countries; by 1990 the ratio had increased to 7,5 to 10.In this sense the wealth gap between the rich and poor countries has widened.Looking ahead,population growth is likely to continue in the developing countries, although at a slower pace,form over 2,0 % p.a. in the 1960s down to 1,75 % in the 1980s.However,because the world' population has already passed the 5,4 bilion mark the actual growth of population will be the largest ever in a single 30-year period,despite declining fertility rates.Thus between 1990 and 2020 the UN anticipates 2,8 bilion more people and in period 2020 and 2050 a further 2,0 bilion people.UN forecasts are for a world population of some 10 bilion by 2050 and the figure could thereafter stabilise at somewhere 12 bilion by the second half of the 21 century.This will provide great chalenges,but also great opportunities for human imagination, adaptation and innovation.Given population growth,mainly concentrated in the developing countries,it will be dificult to increase rapidly the per capita use of energy.

Having in mind the development of world's population,the two fundamental challenges are crucial. Others exist, but the two appear to be:

- that 40 % of the world population currently has no access to commercial energy,one of the basic ingredients required to achieve an even minimal existence.With world populations expected to grow from the present 5.8 billion to 8.0 billion in 2020 and to 10.0 billion or more by 2050, unless commercial energy services can be made available, particularly to rural and peri-urban societies in many developing countries, it is likely that the deprived 40% today may rise to 50% or even 60% of the world's population by the year 2050. Economic regression means instability.

- tbat the pathway to sustainable development still requires a universally accepted definition, and action is required to adapt to it, not only in the energy but also in many other sectors. The imperative priority remains for economic development, but the potential impact of such development on local and global environments equaily require honest and courageous protective action.

What is the basic characteristics of the world energy situation? : - INCREASE OF ENERGY EFFICIENCY-In many countries are agreeed in giving very high priority to increasing the overall eficiency of energy use.There are several reasons for seeking to improve energy efficiency in all countries :improving economic efficiency;reducing environmental impacts ;reducing dependence on imported energy,especially oil;increasing the efficiency with scarse domestic resources of energy are used;conserving finite energy reserves and inhibiting future energy price rises.Historically, relative increases in the real prices of energy, as compared with other prices, has been the principal driving force for improving energy efficiency. Additional means by which energy efficiency will be influenced include: regulation; technology; psychology of avoiding waste; information to consumers on energy efficiency and costs; and localized physical shortages.

- ENVIRONMENTAL CONSTRAINTS TO ENERGY CONSUMPTION- Concern about the increase in greenhouse gases and potential global warming is verry intense today, with many studies of causes, impacts, responses and costs.It isn't expected that developed countries, much less the developing countries, will agree to limit significantly the consumption of fossil fuels (or the rate of deforestation) during the next one-two decade. It does seem likely that there will begin to develop some consensus on prospective impacts, responses and costs - as well as some consensus on how difficult it is to establish, by political means, the rates at which greenhouse gases are to be added to, or removed from the atmosphere.

The concept of limiting use of fossil fuels, and thus global warming, is being pushed by some environmental and political interests, principally in the developed world. Since only nuclear power,new and renewable sources and hydropower (or non carbon burning) energy may be considered completely "user friendly" as related to global climate change,these could yet become perceived to be the premium energy resources.This won't happen in the near term.More likely,the use od oil,natural gas and "cleaner" coal will increase until their use is selectively limited by resource and price factors,or environmental regulations based on "clear and present danger" signals-signals which are not yet generally recognized. - ENERGY POLICY IN WESTERN EUROPE-In Western Europe we have common energy policy,with goal to provide more secure supply,investment assistance in developing and using energy more efficiently and with minimum environmental impacts.

- CESSATION OF OPEC DOMINATION-Today OPEC supply world energy market less than 40 %.It had been more than 60 % in the 70s.

- INTENSIVE RESEARCH OF ENERGY POTENTIALS AND NEW TECHNOLOGIES - Techology is a potent weapon for achieving a transition to a sustainable future.Much can be done to reduce the environmental impacts of energy use.The technological efforts in the energy field are made in three directions:to improve the efficiency with which we produce,transport and use energy;to develop completely new energy systems and to reduce the adverse environmental impacts of energy use. Commercial fossil fuels supplied over three quarters of the world' total energy requirements in 1990,and even though non fosill energy sources are expected to increase their share,fossil fuel supplies will continue to meet the bulk of the world's energy requirement for a long time to come.That's why we are in time of intensive research of energy potentials. In the table 1 and 2 we have the world and OECD countries energy potentials on the basis of World Energy Council estimates in 1990:
 
 

Table 1 - Proven reserves and potentials of fossil fuels and their life cycle

Fuel type                                  Proven reserves         Potentials         Total

Convetional liquid fuel               150                                 145                295

Non-convetional liquid fuel        193                                 332                525

Total liquid fuels                          343                                 477               820

Natural gas                                  141                                 279               420

Coal                                              606                               2794            3400

Total fossil fuels                         1090                               3550            4640

URANIUM:

In thermal reactors                         57                                 203              260

In fast reactors                            3390                             12150        15540
 
 

On a global basis, there appears to be adequate energy supplies in useful forms at acceptable prices. Problems will continue to arise because of the distribution and control of those resources as compared with geographical patterns of use. There are also difficulties in transport for oil and, to a lesser extent, for gas and coal.
 
 

Table 2. Energy reserves and static life cycle in OECD countries

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Fuel type         Proven reserves         Compared to world    Static cycle
                     Gten                              %                                            god
-----------------------------------------------------------------------------------------------

Coal                     164,7                                     28,7                           208

Oil                            7,2                                       5,3                              10

Natural gas            11,4                                     11                                16

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WORLD ENERGY DEVELOPMENT UNTIL
THE YEAR 2020 AND THE YEAR 2050:








First let us remind ourselves of the basic analysis derived from the WEC Commission report "'Energy for Tomorrow's World" with its retained horizon year of 2020. Global population be that year will rise from today's 5.4 billion people to 8.0 billion (UN medium estimate) and global economic development will run at between 1.6% and 2.4% annual growth.

The four planning scenarios built into the Commission show increased energy demand of between 65 % and 95 % by 2020.What will this mean?

- It will mean that by 2020 more than 90 mil. barrels of oil per day will be consumed, an increase of some 27 mb/d or the equivalent of the whole of today's OPEC production.

- It means that coal output will double to about 7 bilion tonnes per annum,more than twice th UK's or Canada's known total reserves.

- It means that gas demand will more than double, to reach some 4 trillion cubic metres, almost as much as the USA's current total gas reserves.

- It means that more electricity generating capacity will be built over the next 25 years than in the previous century.

- It means that 90% of this energy growth will take place in the currently defined developing countries particularly in Asia and in Latin America.

- It means that those developing countries wliich today consume 30% of the world's total energy will consume 50% by 2020 and probably 70% by 2100.

- It also means that by 2020 those same developing countries will emited more CO2 from fossil fuel burning than the CO2 emitrted by the whole of the industrialised world in 1990.

And it means that by 2020 73 % of the worid's oil reserves and 72% of its gas reserves are likely to be concentrated in only two major areas, the Middle East and the CIS. Will this factor and the increased supply lines they imply lead to more, or to less, security of global supplies?
 
 

ENERGY IN THE YEAR 2050: why do we need to look so far ahead?
 
 

We need to look ahead,to energy in the the year 2050,for four reasons:
 
 

o world population will grow from 5.3 billion people today to something in the order of 10 billion by the middle of the next century,
 
 

o meeting concern about climate warming requires a time horizon reflecting the strategic nature of this problem.
 
 

o we need to decide on our research and development strategies; and finally
 
 

o the decisions we wll take in the 1990s will largely determine our longer-term strategic responses well into the 21 st century.

From a policy point of view the requirement is to ensure that actions which are developed for the short and medium term are indeed coherent with longer term needs. The current energy system does not always lend itself to prompt and flexible responses. But the continuation of current trends in energy supply and use is not sustainable in the long run. Three objectives, generally related to welfare, are critical to the outlook for energy:
 
 

o economic growth
 
 

o affordable energy services
 
 

o environmental protection.
 
 

But there can be stresses between these objectives.Two scenarios illustrate the nature of these stresses.Today commercial energy consumption is in the order ot 8 billion tonnes of oil equivalent (Gtoe) per year. lf energy eficiency improvements and changes in the energy supply mix are effective then we might look to a world in 60 years' time consuming about 15 Gtoe, with most of the growth coming from developing countries (table 3). However, continuing to implement current approaches to those problems would lead us to a world consuming over 20 Gtoe.
 
 

These two illustrative energy futures imply differing global priorities for these objectives, especcially between regions. A conflict of aims is nowhere more likely, than in developing countries where the continuing growth in population will mean an increasing need for more and better services that require energy.Without such services, economic and social development will suffer.
 
 

Any conceivable increase in energy efficiency will be offset by the growth in population and energy consumption per person in developing countries. Our own efforts in Europe to reduce C02 emissions will be overshadowed by the increase in developing countries.

The leading question is how to get into a sustainable growth path that reconciles the social and economic aspirations of the world's peoples for higher welfare while at the same time meeting concern for a cleaner environment and avoiding the dangers of global warming.

Table 3. The egological projections of world energy consumption

Fuel                 1960             1990             2020             2050

    Gten             Gten (%)     Gten (%)     Gten (%) --------------------------------------------------------------------------------------------

Coal                 1,4             2,3 (29)            3,0 (24)         4,0-5,0 (23-33)

Oil                   1,0             2,8 (35)             3,8 (30)         3,0 (20)

N. gas             0,35            1,7 (21)             3,7 (29)         3,0 (20)

Nuclear e.      0,0                 0,4 (5)             0,7 (6)         1,0-1,5 (7-10)

Hydro             0,15             0,5 (6)                 0,8 (8)         1,0 (7)

New renew.   0,0                 0,2 (3)               0,6 (4)         3,0-1,5 (20-10)

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Total             2,9             7,9 (100)             12,6 (100)         15,0 (100)

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|
 
 

Figure 3. Projections of world energy consumption


 
 

From a global perspective coal and other fossil fuel resources are still plentiful. Applying a less restrictive reserve concept,the physical availabilities of fossil energy resources are unlikely to emerge as the limiting factor during most of the 21st century.

Over the next century,the contribution of fossil fuels to total energy supplies will largely depend on abilitv to meet energy service demands in an environmentally acceptable way.Cleanness, comfort and quality of service,rather than simple availability,will become the benchmarks for coal and other fossil fuels.
 
 

COAL:






Global coal reserves are reasonably well defined and ample as compared with oil and gas. Market prices for coal (and gas) will continue to be related to the world price of crude oil. Transport cost and provision of shipping facilities will become less constraining on the use of coal internationally. However, even as "clean coal" programs bear fruit,coal utilization will incresingly raise environmental concerns. Notwithstanding, newer methods of mining and burning coal are leading to enhanced safety and significantly reduced environmental impact.
 
 

Coal will further retreat from decentralised uses in the industrial and commercial sectors. Electricity and district heat production may remain a domain for coal as long as regional-scale environmental disturbances can be avoided. Add-on scrubber and catalytic conversion technologies have demonstrated that coal combustion processes can be adequately cleaned up and that smog and sulphur dioxide emissions can thus largely be avoided.
 
 

Perhaps with the exception of CO2 removal, coal-fired electricitv and cogeneration production capacity of the 21st century will not rely on scrubbers and similar abatement technologies. Rather. stripping pyrolitic sulphur and other impurities from high sulphur coals will occur during the benefaction stage prior to combustion.
 
 

The low sulphur coal would then be burnt in pressurised fluidised-bed combustors (PFC) or integrated coal-gasification combined cycle (IGCC) systems.
 
 

Several other new coal conversion technologies also crack coal into its major elementar components, carbon and hydrogen,before any further processing occurs. As with IGCC plants, the synthesis gas can be used either for electricity and/or heat generation, hydrogen production, or for further chemical processing and synthesis of methane (CH4) or methanol (CH30H). Although substantially cleaner on a regional scale, these approaches do not reduce CO2 emissions beyond those resulting from the efficiency improvements.

Work is in progress to design and develop processes which would produce separate streams of pure hydrocarbon and CO2 or pure carbon.
 
 

Electrochemical processes including gasification and/or hydrogenation with the activation energy, for the reaction coming from electricity offer one possibility, for the pure CO2 approach.
 
 

These and similar processes are in an early design stage and are currently far from technological feasibility. Still, over the coming few decades such processes may well reach engineering maturity and thus maintain a window for coal use throughout the 21st century.
 
 

OIL:


Oil will continue to be the dominant energy resource used throughout the decade and well into the first half of 21 century.Free markets, free trade, and market pricing are seen as likely to work in accomplishing the matching of demand and supply -- most of the time. Notwithstanding, there will be increased acceptance of managed oil markets. Supply security, stability, and predictability of crude oil prices will continue to be important to those nations which do not have adequate indigenous energy resources, as well as to whose marginal cost of production is higher than that in the Middle East. Japan is representative of the former; the United States of the latter.
 
 

New technologies will continue to be explored to assure availability at acceptable prices of liquid hydrocarbons from such non-conventional sources as tar sands, very heavy oil, shales, and ultimately coal. Since these sources greatly exceed those of conventional crude oil and are located in quite different geographic locations, they provide reasonable assurances that liquid hydrocarbons could be available (at some price) for uses such as transport fuels well into the 21st century and beyond.
 
 

From a global perspective, oil will remain a leading energy source up to the middle of the 21st century. The attractive properties of oil and its products are storability,transportability, high energy density by volume and weight, as well as versatility of use. Moveover, the relatively, low investments required in infrastructure and end-use technology make it an attractive option for the growing energy needs of many developing and newly industrialised countries.
 
 

The long-term future of oil in the industrialised world will be highly dependent on a number of demand-side factors:
 
 

o the capacity of the automotive industry to decrease automotive consumption further and to develop improved technical solutions to meet local air qualitv standards;
 
 

o the ability of the oil industry to develop cleaner fuels;
 
 

o the development and improvement of new generations of car technologies based on electrochemical conversion such as batteries and fuel cells, the latter fuelled by hydrogen. This of course will require safe and economical hydrogen production lines and infrastructures;
 
 

o consumer choices between old and new transport arrangements and technologies.
 
 

The potential oil markets of the future will increasingly be linked to the transport and chemical feedstock sectors. In both sectors oil is difficult to replace in the medium term. Electric transport will be improved along new lines: in the early stages battery power will be important, but in the longer term hydrogen and fuel cells could be developed.
 
 

Looking at the supply side, crude oil is certainly a finite resource but not all of the world's reserves have yet been located. In addition to 150 billion tonnes of proven reserves, there is thought to be about the same amount in the uncertain or yet-to-be-found categories. In the long term,operating experience and technology development will allow more oil to be recovered than originally thought likely. Conventional crude oil could last for at least 80 years even at current rates of consumption.
 
 

NATURAL GAS:







Gas resources are relatively plentiful, as compared with current rate of consumption, on a worldwide basis. Natural gas reserves are higly concentrated in the former Soviet Union and Iran. Large natural gas reserves are available in the United States and Canada, as is the related transportation and distribution infrastructure.On a global basis, price, availability and the costs of transport, as well as supply security, will be major influences on decisions of consumers remote from sources of gas supply. Gas will increasingly be seen as the fossil fuel of choice, especially when considering environmental impacts. This status will be tested in the global market as demand and price increase.
 
 

The resource base of natural gas is large. Advances in the geosciences over past decades have led to a better understanding of the magnitude of natural gas resources. The greater depth of most gas reserves requires different and more advanced drilling techniques as compared with oil production. By the early 21st century these technologies will have matured,and as the disassociation of gas from oil progresses, productivity will increase so as to make the production of methane from fields other than conventional oil domains a commercially viable undertaking.
 
 

Furthermore, gas has repeatedly been found in unlikely places. This suggests significantly that gas is more widely distributed geographically than was traditionally thought to be the case.
 
 

Natural gas exists as both "free" natural gas in reservoirs, and below ocean depths and permafrost as solid gas hydrates (methane inside a cage of water molecules(CH4.6H20). Gas hydrates are the largest potential source of natural gas but are normally excluded from gas reserves. The largest reserves are in the Arctic regions of Russia, Canada and the USA. Other deposits exist in the Gulf of Mexico, Black Sea, Caspian Sea and Peru Trough. Estimates of the extent of the hydrates vary enormously but the data suggests that they may amount to over ten times the reserves of conventional natural gas.
 
 

No commercial processes currently exist to exploit these reserves. Heating, depressurisation and adding an antifreezing agent have all been considered. Gas hydrates are a fascinating subject for scientists and technicians but, some suggest, are unlikely to be a significant source of natural gas until well into the next century.
 
 



ELECTRIC ENERGY:



Total energy use has become decoupled from economic growth in the developed countries. However, electricity use remains quite closely coupled with GNP growth. Electricity is increasingly the choice of energy in end-use, in both developed and developing nations. The mix of primary energy resources used to produce electricity will continue in a state of flux: oil with limited appeal; coal as an economcally preferred fuel where available; natural gas being favored in some nations as more economically and environmentally acceptable - subject to supply, price and transport considerations.However,nuclear power will continue to play a strong role with timing dependent on regional demand for electricity and the related availability and cost of both natural gas and coal, as well as hydro and other resources.The option of using nuclear,which will not be limited by its resource basis,should be kept open. However, the commitment to the further use of nuclear power is somewhat precarious in most nations.
 
 

While there are large undeveloped hydroelectric power resources in the world, they are generally not in areas with enough demand for power to make development economic. The transmission of electric power will remain reiatively costly, even with bulk DC transmission.Environmental concerns about hydroelectric development and associated transmission lines will grow.
 
 


HYDROGEN:


Hydrogen and electricity are likely to play major roles in the longer term energy system. Together they can meet most energy service requirements. Hydrogen and electricity are the only carriers that can, together, meet all energy service requirements and do not contain the carbon atom. In addition, both carriers are truly renewable. Electricity, which may be viewed as an electrical charge separation, returns to a neutral charge when it is used. Hydrogen - by analogy water separation - returns to water when it is used.
 
 

lt can be anticipated over the period to 2050 that among the most important end-use technologies, we will witness the decline of the internal combustion engine and all other combustion technologies which close their fuel cycle of carbon oxidation through the atmosphere. The carriers hydrogen and electricity will drive the electrochemical energy conversion devices,catalytic energy converters, electric motors and heat pumps of the future.
 
 

The fundamental key for the hydrogen and electricity tandem is that they are blind to their sources, i.e., they can be produced from a variety of non-fossil and fossil sources. Today's sources and the technology routes used for hydrogen production are still extremely limited, but the range of future options is very large.In the light of the unknown impacts on global cliniate of a continued accumulation of CO2 in the atmosphere, this source flexibility makes the twin carriers hydrogen and electricity the ideal energy policy insurance. Thus, there is no need to embark early on irreversible investment or policy decisions which may foreclose future options.
 
 

Transporting hydrogen over large distances is in principle cheaper than electricity transmission.Hydrogen therefore offers not only a storage option for photovoltaic electricity,which is obviously limited in availability to daylight hours, but also provides a link between large-scale remote photovoltaic sites where conditios may favour production costs and the centres of energy use.Moreover, solar hydrogen opens markets other than traditional electric energy services,such as the transportation sector.
 
 

On the other hand, hydrogen is a relatively dangerous substance:It is the lightest of all elements. It is colourless, odourless, tasteless and non-toxic. The probability of combustion from a random ignition source is greater for hydrogen leakage into a confined space than it is for other industrial flammable gases or gasoline.Also hydrogen penetration through leakage paths such as porous materials, cracked weldings, damaged seals, etc.. is higher than for other fuels.
 
 

In summary, industry knows the necessity of recognising the unique properties of hydrogen and following the safety codes conscientiously. If hydrogen were to be used on a large scale and distributed through comprehensive networks the overheads and perhaps even the technological feasibility of dealing with the increased hazards could become a limiting factor, at least for a time.
 
 

NEW AND RENEWABLE ENERGY RESOURCES:






New and renewable energy sources are generally defined to include hydropower,solar energy,wind,wave energy,biomass,geothermal and oxygenated fuels(alcohols,etc.) and hydrogen.Except for hydroelectric power, these are not likely to play a significant role in the decade ahead. The principal issue for most alternate sources is that of economics, except in unique applications.In those nations where such sources are appropriately and economically competitive with other options, they will contribute to energy supply.Many nations will continue to use biomass(wood,etc.) and biogas to support their developing economies,supplementing them more conventional energy supply in the long run.However,rapid depletion of fuel wood in many regions is expected to create earlier demand for rural electrification.
 
 

While changing technologies and costs offer some favorable prospects,don't count on breakthroughs in alternative energy to eliminate the need for dealing broadly with the environmental and safety issues raised by the current conventional sources of energy-for a long time to come.
 
 

In the longer term,all renewables are good candidates for cost cuts by organisational learning which is particularly inherent in small plants. The leading principle in terms of size and local conditions should be "appropriate is best".
 
 

Renewable energy sources, combined with a system of new technologies, can contribute to a considerable extent to energy requirements in the time horizon beyond 2020. They can also contribute to an energy future which will reconcile the need for economic growth with environental concerns and energy security,without a significant increase in costs - as compared with conventional fuels - and moreover without fundamental technological breakthroughs.
 
 

Alcohol,ethylene, or methanol production biomass in regions with surplus arable land or forestry may contribute to the supply of transportation fuels. But with world population growing and the enhanced use of fertilizers being under critical review,the diversion of productive agricultural land to energy purposes loses attractiveness.Also, growing plants require large amounts of water. Water itself is becoming a scarce resource and thus could present another limiting factor to energy -designated biomass production.
 
 

Direct solar radiation energy is often considered as the ultimate source for electricity and subsequent hydrogen production. Technologies harvesting solar energy directly fall into two categories: central and decentralised.
 
 

Central or solal thermal electricity generating technologies are based on reflective solar collectors that track the sun and concentrate the heat into a heat exchange fluid. The most promising concepts to date operate as hybrid systems, i.e.. in combination with a fossil back-up system to augment the solar heat as needed.
 
 

Decentralised solar technologies include solar panels for low temperature heat generation, usually for space heating or hot water purposes. Because solar heating systems in moderate climate areas still depend on a conventional back-up system or extensive heat storage systems,their future role will depend on adequate passive and active building designs and insulation standards.
 
 

Probably the most important solar energy technology ,the application of which is independent of scale,is photovoltaic electricity generation. Photovoltaic cells generate electricity with no pollution, noise or moving parts.Because there is no working fluid involved they are independent of water availability and thus ideal to operate in remote suny and arid locations with minimum maintenance.
 
 

lt is premature to project which photovoltaic technology will eventually dominate. But over a time horizon of fify or more years, it seems highly likely that photovoltaics will have positioned themselves as a viable electricity production option. For practical applications under typical conditions efficiencies of 20 % to 25 % are expected to be reached in the not so distant future. There will be marked regional variations in scale and application.
 
 

Solar electricity, combined with its storability as hydrogen,could thus overcome its present disadvantages and be capable of playing an important role in overall energy supply world-wide.
 
 

Hydraulic and wind sources are unevenly distributed geographically, which limits hydrogen and electricity production from these sources to regions with sufficient hvdraulic and wind availability. Since wind-generated electricity represents an intermittent source of energy,. hydrogen conversion may help flatten the discontinuities and thus help improve the overall performance of wind converters. One should note, though, that the ever-increasing physical dimensions and accompanying disturbance of hydro power and wind energy projects can cause local environmental concerns to some degree.
 
 

Today, among all new and renewable sources of energy, geothermal energy is the most important producer of thermal and electric energy following hydroenergy and biomass as the "classic" renewable sources. Continuous availablity of geothermal sources not depending on weather conditions, with reliable supply and possible storage represent a great advantage of geothermal energy in comparison with other NRSE.
 
 

An enthusiastic wiew has been expressed in a recent UN report which suggests that using technology already on the market or at the advanced engineering testing stage,by the middle of the next century renewable sources (including solar, wind, hydro and biomass) could account for 60 % of the world's electricity market and 40 % of the market for fuels used directly.The report argues that this could be achieved competitively at energy prices lower than are expected in conventional price forecasts, with the result that C02 emissions could be reduced 25% relative to 1985 levels,while the world economy might be eight times as large as at present.In addition to the expected benefits for reducing air pollution and global warming, the authors argue that a "renewables" scenario would:
 
 

o improve energy security by increasing fuel supply diversity;
 
 

o match social and economic development aspirations in rural areas of the world through the use particularly of biomass;
 
 

o the opportunities for growing biomass for energy on degraded land can of themselves provide the incentives and the financing needed to restore such lands.
 
 

In summary, if the relative position of technologies in their respective technology life cycles is taken into account, they offer considerable promise for future performance improvements.In particular, this means that present achievements at the laboratory level can be transferred to the field.
 
 

CONCLUSIONS:






We can make a number of fundamental conclusions. Let me list the most important ones:

- For the 21 century it will not expected that the world will lack fossile fuels,but on high level of price.A sustainable route to improved living standard is required so that tomorrow's generations can satisfy their own requirements for economic and environmental wellbeing and planning for the energy systems of the 21st century will require non-fossil fuels (new renewables and nuclear) to complement the use of fossil fuels, and this development needs to start now.

- Energy subsidies must be phased out in order for all consumers to understand the implications of the real costs of energy.It was recognised that in many regions this process will take many years. The corollary, if no such action is taken, is that governements, if they subsidise energy, will gradually reduce their financial ability to supply commercial energy, with the subsequent risks of economic regression and increased environmental degradation.It must be advocated the adoption of full cost pricing in order to achieve ultimate sustainability.

- Extending its reasoning further, the interesting point is that many of the facts about the energy sector which today are believed by end use consumers are wrong - and they are wrong because the signals about supply availability, costs and prices, the existing degree of environmental degradation and the state of current institutions which handle such matters, are themselves inconsistent and confused. Institutional changes in a number of key areas, of which finance is one, were strongly advocated. The world will require some US$ 30 trillion over the next 25 years (in 1992 money) with which to develop energy projects. This equates to 50 % more than the entire 1990 world GDP. If such finance is to become available, many radical changes need to be implemented to secure it, particularly with regard to mobilising local capital markets.

Public sector financing of energy (which al 30 % absorbs, worldwide, more finance than any other single element of infrastructure development) is in decline, and is not being matched, particularly in the developing countries, by significant increases of private sector project investment. Certain views appear to have developed within the energy sector that a scarcity of capital may cause real constraints to growth over the next decades. This may prove so, but of more importance, there is an urgent need, particularly in transitional economies like Yugoslavia and in the developing countries, to develop local capital markets from the often relatively high savings rates, and to use this capital through appropriate institutions to finance local infrastructures, particularly energy projects. In the next 25 years we and the World Bank estimate that intemational finance can only cover some 30% of the projects to be built. The remaining 70% of the required finance will have to come from local sources. That, by any standards, is a salutary thought. - The need in the energy sector to achieve the requisite mix of government regulation, economic instruments and market liberation to optimise the security and cost of provision and use of energy, was stressed again and again.

- And finally,improvements to be made to the transparency and general understanding of energy,and what its "sustainable supply and use" mean. Common action to be taken to increase access to commercial energy for the deprived. This is a basic moral responsibility for all countries and nations.
 
 
 
 

ENERGY IN YUGOSLAVIA







- Status of energy potentials,production and consumption in Yugoslavia.

- Trends of development of energy in Yugoslavia up to 2020.
 
 

Owing to its socio-political and economic development after Second World War Yugoslavia grew from an underdeveloped country into a medium-industrialised country.The dynamic economic growth required an equally dynamic development of energy production and use.Dynamic growth of our country requires ever larger quantities of energy to meet predominantly,the needs of industrial,transportation and households consumption.
 
 

The main characteristics of the Yugoslav energetics in year 1990,before the disintegration of SFRY and the beginning of the international blockade and economic sanctions,are:

- Very intensive development of energy capacities in the period of the 70's and of 80's;
Figure 4. Primary energy production




- Very intensive development of production of secondary energy , especially the highly intensified production of electric power in the thermal power stations(more than 80 % of coal consumption),also intensified production of oil products from imported and domestic crude oil and very fast development of district heating sistems in the towns;

- Inadequate reaction on "energy crisis" in the 70's by very high rate of consumption,without supstitution imported fuels;

- The primary energy consumption totalled about 18 Mtoe with the import dependence of 40 %.The per capita consumption rate of primary energy in Yugoslavia,1,8 toe/cap,was among the lowest in Europe,but the aggregate energy intensity rate in Yugoslavia was among the highest ones because of a relatively low social product;
 


Figure 5. Total primary energy consumption


- The final consumption of energy reached the level of 11,8 Mtoe, with very high percent of imported fuels (more than 60 %),especially in oil products and natural gas (about 75 %). Only electric power is domestic source of energy with the share of 20 % in final consumption.

Figure 6. Final energy consumption


- In all previous period the growth of consumption of energy over the growth of the economic activity or the aggregate energy intensity rate in Yugoslavia was among the highest ones in Europe,which is indicative of an inefficient utilisation of energy;

- Very high dependence of imported energy,covering up to 40 % of the total energy consumption,especially in crude oil and natural gas;

- Very intensive investments in energy capacities.Only in electric power industry in the period of 1975...1990 are invested 15 billion USD.

- There were frequent changes in control policies and mechanisms of energy prices.
 
 

In other words the previous development of energy in Yugoslavia have not been sufficiently realized the required and expected results regarding a more significant involvement of indigenous energy resources, regarding a longer-term change in the structure of consumption ,rationalization of the total energy consumption,as well as the substitution of imported fuels by domestic energy sources, primarily by coal.The fact of the country's relative poverty in energy resources(from the standpoint of world criteria) didn't make any impression on rational use and save of energy.
 
 

Besides that, in the period of sanctions and economic blockade,in addition to agriculture, the energetics of Yugoslavia behaved the largest load in maintenance of our economy and society.Energetics,as a main infrastructure branch,in previous SFRJ has been optimised on the level of state and before the economic sanctions,the consequences of disintegration first exerted influences on energy industry.In 1991 has stoped to work Yugoslav oil pipeline Krk-Pancevo and interrupted the network of the electric power suply system of Yugoslavia and the connection with the West European UCPTE interconnection.The second blow on Yugoslav energetics has been on May 1992 with economic blockade.
 
 

The shortage of imported fuels and the impacts of the international blockade contributed that domestic production of energy have been obliged to preserve high level of production (practically only of yugoslav industrial branches) to supply industry and households.In that period the energy supply sector of Yugoslavia was suffering very much resulting in the following:reduction and discontinuation of prospecting for energy raw materials,difficult economic position resulting from a non-economic prices of energy sources, deteriorated reliability od production fiacilities and supply to consumers, discontinued investment in energy sector,personel losses,etc.The consequences of sanctions will have very high price for the energy industry and will be felt for many years to come and to be in the position it have been in the beginning of 90's.
 
 

The sanctions exerted influeces on change of the structure of final energy consumption.In the period of economic blockade,because of high imoport dependence of oil and gas industry (about 4/5 of quantity),and the structure of energy consumption in our country has been changed (Table 1) :
 
 

Table 1. The level and structure final energy consumption in Yugoslavia
 

Sort
1990
1995
ratio

95/90

Mten
%
Mten
%
solid fuel
1819
15,4
1065
16,4
0,585
oil products
5574
47,2
1598
24,6
0,287
natural gas
2019
17,1
1371
21,1
0,679
electric power
2397
20,3
2462 
37,9
1,027
total 11809 100,0 6496 100,0
0,550

 

In this table is obvious that in 1990 the participation of oil and natural gas in the structure of energy final consumption was 64,3 %,, the same as in western countries.But after the economic blockade it have been 45,7 % or very low percent.The oil and natural gas have been supstutute by domestic source,electric power,very cheap energy source, without any possibility to improve energy efficiency or to use other energy source.

In the period of 1995 and 1996,in the time of the influence of economic blockade,was finished the "Strategy of Development of the Energetics in the FR of Yugoslavia until the Year 2020 with a Vision of the Period to 2050" .The STRATEGY was prepared for the purpose of showing,on the basis of an appraisal of the long-term needs and a systemation of all resources,the direction to be taken towards a lasting harmonious and tenable development of the Yugoslav energetics.
 
 

Although,after the end of economic blockade and sanctions of UN Security Council ,the state of energetics became better,it is very complex too.In the past two years became evident that the STRATEGY and also the Middle-term plans of Public Energy Entreprises didn't realized .Today the economic situation in the field of energy is very heavy, the prices of energy is not high enough to cover the cost of normal operation.Also the development of economy and industry is verry slow.
 
 

The development in 90's and present state of energetics of Yugoslavia, before the war and bombing, must be defined by some main characteristics:
 
 

1.The structure of domestic energy resources is a uniform one to a large extent.The energy resources of Yugoslavia are mostly in the lignite reserve(about 80 % og geological reserves) and much less in hydroenergy,cryde oil,gas,uranium ,oil shale,etc.The geological reserves are more than 4 billion tonnes oil equivalent (toe=42 GJ), in which the share of the coal is 85 %,of crude oil and natural gas 1,5 %,oil shales 4,8 %,hydropower 5,7 % and uranium 2,7 %.More unpleasant situation is in proven reserves, where the share of coal is 99 %(lignite more than 92 %) .But the abundance in lignite reserve and the fact that 90 % of reserves is located in four big basins (Kosovo,Kolubara,Kostolac,Metohija) makes it possible to maintain the country's exixting energy self-sufficiency degree and possibly increase it.According to what is known at present,the total usable hydroenergy amounts to about 27 000 GWh,of which only about 12 000 GWh have been activated so far.The big difference between estimated geological and proven reserves of crude oil and natural gas shows that they haven't been prospected for enough,particularly in Republic of Montenegro.With the development of commercial technologies,greater importance could be attached in the future also to the oil shale and uranium reserves.The potentials of the new and renewable energy sources are considerable and important for FR Yugoslavia because there are favorable conditions for their use taking into account the availability of the resources,but it is still uneconomically in many fields od aplication.
 
 

2.The production of coal (Table 2) is enough for the prodction of electric power in thermal power stations,but it is evident the problem of shortage of the high-quality coals for industrial and general purposes and all quantities of coke.The existing reserves will not be a limiting factor for a bigger production.The consumption will be ,more than 80 %,in thermal power stations for producing electric energy. The production of crude oil and natural gas covered just a little more than 20 % of total needs .The maintenance of the existing level of self-sufficiency and its possible improvements call for an intensification of exploration in the country and concession-based linking on the basis of long-term arrangements in the country and abroad,which could cut the direct import dependence.
 
 
 
 

Table 2.The production of primary energy ,000 toe
 

Sort
1990
1995
1996
1997
1998**
Index %
95/90
98/90
Hydropower
814 
1053
1250
1098
980
1,29
1,20
Coal
8329
7515
7200
8007
8068
0,90
0,97
Oil
1074
1067
1027
992
992 
0,99
0,92
Natural gas
564
739
556
592
598
1,31
1,06
Total
10781
10374
10033
10689
10638
0,96
0,99

* tone oil equivalent (toe = 42 GJ)

** plan







3.The capacity of the facilities for the generation of electric power is about 10 000 MW,of which about 6000 MW is accounted for by the coal-fired thermal power stations,with the possibility to produce about 40000 GWh per year.In the table 3 is shown the data about the production of electric power(neto) in the period 1990..1998.The available primary energy potentials are such that it will be possible to expand the production of electric power also in decades to come on the basis of the country's own resources-lignite and hydropower.
 
 

Table 3.The production of electric power in Yugoslavia, GWh
 

Sort
1990
1995
1996
1997
1998*
Indeks %
95/90
98/90
Hydropower plant
9372
12200
14540
12762
11394
1,30
1,26
Therm.power plant
28910
22282
20718
24664
25789
0,77
0,89
Total
38282
34482
35258
37426
37183
0,90
0,97
EPS
35268
3306
33280
35246
34702
0,94
0,98
EPCG
3014
1476
2984
2180
2481
0,49
0,82

*plan

The capacity of the facilities for the primary processing of crude oil is about 7,8 milion tonnes and ,with the modernisation,are enough for the future.The capacity of the facilities for the production of dried lignite is about 2 million tonnes.
 
 

4.The basic network of the electric power supply system of Yugoslavia is linked with the systems of the countries in Yugoslavia's neighbourhood by 400 kV lines.The powerful electrical transmission network enable quite reliable and economic operation of the electric power system in Yugoslavia globally having created opportunities for more intense usage of the domestic sources of energy.The gas pipe line system connects all the gas fields in Vojvodina with the consumers. It also makes possible the imports of gas from Russia through Hungary and transit of gas to the former Yugoslav Republic of Bosnia and Herzegovina. The total length of the system is 1669 km, of which 624 km of supply lines and 627 km regional lines. The capacity is 3.8 billion cu.m. in Vojvodina and 1.715 billion cu.m. in central Serbia.
 
 

5.The primary consumption of energy in the period after the end of economic blockade and sanctions of UN Security Council had very intensive growth (fig.7), that in this year is about 90 % of the consumption in 1990.This is not in harmony with the projections in the STRATEGY /1/ because is much more than the level of consumption in medium variant and close to optimistic variant.

Figure 7. The consumption of primary energy



6.In the same period the structural changes in the final consumption of energy have been evident.Under economic blockade and sanctions of UN Security Council,without possibilities to import high quality coal,crude oil and natural gas and in period very low prices of energy sources ,the industry and households have used much more the domestic sources of energy,especially electric power(figure 8).


 

Figure 8. The consumption of electric power




But after the period of economic blockade, the using of energy in Yugoslavia didn't changed.In households used electric power for heating purposes as much as possible,and in the same time was very high import of crude oil and natural gas and verry high final consumption of energy (Table 4).It isn't in the corelation with the projections in the STRATEGY/1/.
 
 

Tabela 4. Growth of final consumption of energy in Yugoslavia

Indeks 1990 = 100

Sort/Year
1990
1995
1996
1997
1998*
Electric power
100
105
112
117
117
Oil products 
100 
36
60
73
77
Naural gas
100
54
86
93
110

 

The projections of the future needs in energy have been prepared by using a multi modular model.The model is based on an energy-technological aproach,in line with the volume of physical activities and energy-economic or energy-technological indicators and potentials of energy saving.
 
 

The total final consumption of energy(fig.9) will reach the 1990 level (12 Mtoe) around the year 2005 and by 2020 it will reach 18 Mtoe,which is by 50 % more thab in 1990.In 2020 the energy intensity,measured on the basis of final consumption will be by 18 % lower than in 1990,as a cumulative result of risen efficiency and restructuring of the national economy.

Figure 9. Final energy consumption by sectors




The chief long-term movements in the structure of final energy consumption (fig.9.) should go towards : a decrease in the share of liquid fuels,an increase in the shared of gas,a decrease in the shared of solid fuels,a gradual decrease in the currently very high share of electricity and gradual introduction of new and renewable sources of energy.
 
 

According to the projected final consumption and its structure,the total consumption of primary energy will be about 26,6 Mtoe in 2020,which is by about 46% more than in 1990 (Table 5).






The per capita energy consumption rate will be about 2,3 toe in 2020,which is about 75 % of the average consumption in developed countries in 1990.The share of coal will still prevail in the structure of the total primary energy production,and the share of gas will increase significantly (fig.10).Together with the concession-based production,the import dependence would be about 42 %.
 
 

Figure 10. Total primary energy consumption
 
 
 

DEVELOPMENT OF ENERGY SUPPLY SECTORS


Solid fuels
 
 

The estimated consumption in the period ending in 2020(fig.11) will call for the development of facilities for an output of about 65 millions tonnes a year,for which the existing reserves will not be a limiting factor.This consumption will be ,more than 80 %,in thermal power stations for producing electric energy.

Figure 11. Solid fuels consumption





Oil
 
 

It has estimated that in 2020 the consumption of liquid fuels will be about 7,5 milion tonnes(fig.12) or about 660 kg per capita( 50 % of the average of OECD ).This is about the existing capacity of oil refineries.The reserves of oil in country are low.The maintenance of the existing level of self-sufficiency and its possible improvements call for an intensification of exploration in the country and concession-based linking on the basis of long-term arrangements in the country and abroad,which could cut the direct import dependence (fig.12)

Figure 12. Liquid fuels consumption




Natural gas
 
 

An increase in the share of natural gas in covering the needs in energy was set earlier as a strategic options in the development of the energy supply industry.The consumption of gas (fig.13) should increase at the highest rate as the result of substitution of other fuels and increased demand,and by 2020,it should reach about 6,2 billion m3 and cover the total energy demand by 20 %.Most of that consumption will be imported.The future domestic production will be afected by the naturally diminishing production in the gas fields currently in use.

Figure 13. Natural gas consumption





Electric power
 
 

According to the projections,the 2020 output in electric power will be about 47 TWh while the required output,including transmission and distribution loses will be about 54 TWh.In terms of specific electric consumption,Yugoslavia is much closer to developed countries than in the case of other energy sources.The available primary energy potentials are such that it will be possible to expand the production of electric power also in decades to come on the basis of the country's own resources-lignite and hydropower.It woul be necessary to strive for a greater application of new and ecologically better coal utilisation technology,such as fluidised bed combustion and combinaed cycles.The relative abundance in lignite reserves makes it possible for a part of such reserves to serve as the basis for the construction and operation of thermal power stations together with foreign partners.
 
 

New and renewable energy sources
 
 

Most of the NRES are stil in the phase of development and industrial research.The chief objective is their greater utilisation for autonomous and local purposes,for the needs of the "small scale power industrie",to meet the demand in low temperature heat in the first place.

Their importance will be increased in FR Yugoslavia too along with the development of economical technologies for their use which is expected in the next century when high-temperature energy needs and electric energy production are concerned.
 
 

CONCLUSIONS







The transition to a sustainable energy system requires more than just marginal adjustments or the replacement of certain energy sources. The transition must proceed from the level of energy services and end-use technologies.The long-term policy target for energy system development must be to encourage the transition to energy systems in which the fluxes to and from the system are coherent with nature's fluxes and do not perturb nature's equilibria. Only then will it be possible to provide for economic growth without environmental costs undermining the gains.
 
 
 

THE GEOTHERMAL ENERGY IN FR OF YUGOSLAVIA
 
 

New and renewable sources of energy (NRSE) are specially important for FR of Yugoslavia because there are favorable conditions for their use taking into account the availability of the resources. Even though their research has already started twenty years ago, the results obtained until now demonstrate clearly that although many optimistic expectations were not accomplished, owing to favorable local conditions in Yugoslavia, the NRSE have already been used to meet various low-temperature energy needs (particularly solar and geothermal energy). But with the exception of hydroenergy and the most frequent conventional renewable resources (biomass and agricultural wastes), it is not possible to speak about a real energy balance of those resources because their usage is verry small.
 
 

New and renewable sources of energy will have more importance in the next century because they will enable fulfillment of energy needs without considerable ecological problems; they will also enable a greater substitution of conventional fuels, particularly oil and gas. It is of a special interest for our country because as already stated, we have considerable potentials of NRSE and we do not have sufficient high quality sources of energy.
 
 

It is generally known that Yugoslavia, especially Serbia, lies in the zone with favourable geothermal conditions . This zone starts from Hungary on the North , expanding to the areas of Greece and Turkey and further up to the East. But Yugoslavia is one of the few European countries in which systematical measurements of the essential geothermal parameter- the terrestrial heat flow, have not been carried out. Thus, for the purpose of evaluating the geothermal energy potentials in Yugoslavia and, also, in Serbia, the estimates of these values are given on the basis of general geological and geotectonic data, minor measurements, results obtained by hydrogeological explorations and the results of geothermal investigations in neighbouring countries. Generally speaking, the explorations rates are still very low and further geological, hydrogeological and geophysical explorations, including deep well drilling, will be necessary.
 
 

The principal indications of a possible geothermal energy source are temperature and heat flux which depend on the origin and distribution of terrestrial heat sources in the earth's crust. According to our present knowledge, the most probable causes of the positive terrestrial heat flux values in Yugoslavia are the heat emanating from young neogenic igneous intrusions, heat conducted from the lower depths of Earth and heat generated by the radioaktive elements decaying in acid igneous intrusions. Studies of the thickness of the Earth's crust by deep seismic methods show that in Yugoslavia the crust is from 25 to 40 km thick. Acordingly, it can be considered that the average values of regional heat flow due to heat conduction from the Moho Discontinuity will amount to about 80-100 mWm-2 , much more that the values for Europe (Europe cca 60 mWm-2). Also, some parts of the Earth's crust in the territory of Serbia underwent intensive magmatic activation in the Tertiary, and particularly in the Neogene, and numerous granitic rock intrusions were formed. According to the results obtained so far the area of Tertiary magmatism and particularly of Neogene magmatic activation, appears to be the most promising for the geothermal energy use in Yugoslavia, In this areas heat flow values can be several times higher the average (up to 200 mWm-2 ). It is realistic to assume that the terrestrial conductive heat flux averages, are no less than 100 mWm-2 ,in 30% of Serbia's territory and that these regions thus qualify for thorough exploration conducive to future economical use of their geothermal potential. The conductive heat, i.e. energy reaching the surface, totals 50.10 15 J. Temperature measurements are also still rare even during geophysical logging. That is why it is possible to make just an estimate of the potential and even that only individual areas rather than for Yugoslavia as a whole.
 
 

The relatively low level of investigation of Yugoslavia's territory, notwithstanding the results of various geological, geophysical and hydrogeological investigations, initial geothermal investigations and data available on natural thermal springs, make it possible to assess Yugoslavia's geothermal energy . It is confirmed by the fact that in our country there are numerous spas and natural springs with water temperatures over 300 K (fig.1.).The hottest are the thermal springs at Vranjska spa : with 94 oC these are also the hottest natural springs in Europe.
 
 

Systematic research in Vojvodina started in 1969 when the first hydrothermal hole was bored - Subotica S-l, and to date, 68 holes were bored with the average depth of 800 to 1200 m. Besides, 42 negative oil-gas holes were tested to ascertain possibilities of their utilization as geothermal holes. Out of 110 tested hydrothermal, oil and gas holes, only 24 are used today; only 11 holes are used for heating. Based on the research activities to date, it has been concluded that a larger part of Vojvodina is very promising for obtaining geothermal waters up to the temperature level of about 363 K.
 
 

In the previous period, in the central part of Serbia, mineral and thermal waters were registered at 241 localities - over 90 % were natural and only 8,8 % were discovered by boring. 1080 natural and "artificial" springs of thermal waters were registered in these localities. Out of 241 localities, hydrothermal research was carried out on 128; on 89 localities exploitation boring was done. From 1965 to 1992 the total of more than 300 hydrothermal holes was bored. Besides, thermal waters were registered in 40 oil-geological holes and 37 other purpose bored holes. All springs with temperatures over 20 oC yield on the average about 1800 lit/sec,i,e. over 155.000 m 3/day whereas the yield of springs with water over 30 oC exceeds 60,000 m3 /day: this means that the geothermal energy surfacing from those springs totals about 3.10 15 J per anum.
 
 

The temperature, physical and chemical composition, yield, place and flow of the above thermal and thermomineral springs, the geological composition, hydrogeological and general geothermal conditions of the cities and their environs show that there are major deposits and sources of geothermal energy. This is the reason that until a few years ago there were hydrogeological and geothermal investigations in the vicinity of hydrogeothermal phenomena, aimed at increasing the capacity and temperature of the existing natural hot springs. These investigations have been in Vranjska, Ribarska, Lukovska, Prolom, Mataru{ka and Selters spas where many wells were drilled. Also hydrogeological investigations were conducted in Vrnja~ka, Sijerinska, Kur{umlijska, Ni{ka and other spas, with positive results for the capacity and temperature. By virtue of the effektive financing system once this objektive was successfully achieved, the investigations would be discontinued and possibly resumed only when the relevant spa's water consumption would reach the spring's operational capacity. This means that no modern hydrogeothermal system in Yugoslavia has yet been studied in its entirety and that exploratory drills seldom went below 1000 m.
 
 

It has been mentioned that only lately we have become witness to some attempts to explore sites without visible natural manifestations, where geothermal indications emerge from other kinds of research. These investigations were in the vicinity of Prokuplje, Lazarevac, Ljig,Beograd and the best results are achived in the region of Macva. Hydrogeothermal investigation in Macva began in 1981, and in the past years, although not completed, revealed large low temperature hydrogeothermal resources of European , rather than national, importance.Neogene sediments in Maeva have a thickness of 200-1500 metres, over Triassic karstified limestiones and dolomites.Thermal waters are found by drilling in six localities, so far from one to the other. The most signifikant occurrence was that at Bogati}: discharge from the small-bore well was 37,5 l/s and water temperature at the well head 75 oC. The highest expected temperature in the reservoir is about 100 oC. Geothermal energy accumulated in thermal water in this aquifer is estimated at 3.2.10 15 kJ.Natural conditions in Macva are favourable for an intensive exploitation of geothermal energy. Also, the quality of all water discharges was close to that of drinking water. While preliminary, the given hydrogeothermal data suggest a very large geothermal resource in Macva as an excellent source of economic geothermal energy production.
 
 

Based upon data obtained until now it may be estimated that there are very promising regions in this part of the country such as: parts of Panonian basin, Ma~va, Posavina, Tamnava region, Pomoravlje and Podunavlje , the regions of Vranje and Toplice, and many others. If the use of existing natural springs and holes in Serbia up to 300 K is analyzed, which today is technically and economically justified, the following values are obtained:
 
 

Table 1 - Geothermal resources in Serbia

-----------------------------------------------------------------------------------------------

Region          Possible production      Thermal power      Energy saving

-----------------------------------------------------------------------------------------------

l/s                              MW                    toe/year -----------------------------------------------------------------------------------------------

Central Serbia             688                       90                     20.000-40.000

Vojvodina                     741                       85                     18.000-36.000

Kosmet                         229                      14                          3.000-6.000

------------------------------------------------------------------------------------------------

TOTAL:                     1658                       189                     41.000-82.000

-----------------------------------------------------------------------------------------------
 
 

Research of the geothermal energy for its faster development in Serbia is a multidisciplinary activity and needs huge financial investments. For this reason rational use of such financial sources is iniportant for each phase of the exploration. First, we have to start with measurements of the heat flow, as a background for further investigations. Where we have an indication of geothermal anomalies, detailed geological, hydrogeological and geophysical measurements have to be provided before exploratorry driling. And also,the explorations which started in Macva and other sites should be continued for determination of geothermal energy resources.
 
 

Geothermal energy has been known for thousands of years now, although it has been used for balneological purposes. Today geothermal energy is basically used to supply heat energy, generate electric energy and for balneological and recreational purposes.

The investigations conducted so far have not yet justified the expectations regarding high thermal fluid temperatures alowing economical generation of electric energy, but showed that they were quite adequate for the supply of heat (to heat houses and dwellings, hot water, green-houses, hot-houses, stables and fishponds, air conditioning, etc), i.e. they could meet the low temperature requirements in the major part of Serbia.
 
 

In our country, thermal energy as the form of the geothermal energy is today applied at the most in recreation centers; in most of spas in our country the thermal energy is used for heating, preparation of hot running and basin water by which the electric energy and conventional fuels are considerably substituted.At present geothermal energy sources, chiefly, are exploited in 42 places in Serbia; of them, 4 served to built health and tourist resorts which now enjoy international prestige; 16 sites have been turned into modern regional health and recreational centres, and the remaining 16 are thermal springs used by the local population in a rather primitive way. Other natural or man-made hot springs are not exploited yet,although this would represent a major social advantage. In addition to its health and recreational application the water from thermal springs is only seldom used to supply consumers, far below their overall heat potential. For the heating purposes geothermal energy is used in many spas (Prigrevica,Melenci,Vranjska, Sijerinska,Jo{ani~ka, Ribarska, Ni{ka,Kur{umlijska,etc), but in much more spas and sites, where geothermal energy is occured, the projects for utilization are under way.

In other words, of the total amount of water currently flowing from hot springs, about 15 % are put to properly organized modern use, mostly in balneology, although the geothermal energy possibilities are in reality much greater. But the problem of larger utilisation of geothermal energy is the capital requirement. This cost is more than most local organizations could possibly finance out of their own revenue and profits. Because of that for further intensive utilization of geothermal energy, some system solutions, especially concerning the financial problems, are indispensable.
 
 

Today overheated, dry-saturated and wet vapors and hot thermal waters are used for production of electric energy. For us, particularly interesting are thermal models of using hot thermal water for production of electric energy through binary cycle as until now we do not have natural thermal springs of temperature over 400 K.
 
 

Although in Serbia the utilization of geothermal energy is not yet practiced on a large scale, scientific research institutes and faculties have developed many techmological schemes for the utilization of geothermal energy for certain sectors of consumption (agriculture, households, balneology and recreation, etc,). Many original projects for the use of geothermal energy with various physical and chemical properties of thermal waters have been elaborated, and the construction of pilot plants to be used in agriculture, district heating and balneary and recreation needs, are initiated. Special attention is paid to the geothermal installations with heat pumps, because, when balancing the useful potential, diferent values are obtained depending on whether the heat pumps are used or not. Application of thermal pumps and use of low-temperature thermal waters for heating, hot water and air-conditioning would contribute to a greater use of geothermal energy; important experience has already been obtained in our country with relation to the above use.
 
 

Having in mind importance of geothermal energy in Yugoslavia intensive R/D work has been completed over the past years and represents a good base for faster utilization of geothermal energy. The application of geothermal energy in Yugoslavia can grow faster only if low temperature requirements are satisfied to a greater extent. At present, this would be technically and economically justified. Nonetheless, if such plans are to become operational, it is necessary not only to find financial resources which are always lacking, but also to mobilize and organize the society towards this goal. Relevant agencies should adopt regulations bearing on all matters concerning investigation, exploitation and use of the geothermal energy including estimates of reserves, resources and their potential. Prospecting for geothermal energy is a high-risk activity, much more so than the investigation of other energy fuels and requires larger funds.To mobilize the society for broader geothermal energy utilization, it is necessary to exploit the already investigated geothermal springs without delay, especially the region of Ma~va, and incorporate them in Yugoslavia's energy balance and thus substitute conventional fuels.
 
 

Previous results of research and use of geothermal energy contributed to its greater application within the bigger part of our country. Taking into account that only a smaller part of the available geothermal capacities is used today (in Vojvodina only about 9 %, and similar in the central part of Serbia) the realistic estimates are that if the available capacities are used, it will be possible to substitute oil from 80.000 to 120.000 tons per year, already around the year 2005. All the more so because many towns have favorable local conditions for centralized use of geothermal energy and the most promising geothermal sources are located in the agricultural regions (Vojvodina, Ma~va, Podunavlje, Pomoravlje, Stig, etc.) where it is possible to construct greenhouses, hot flower beds, or fish ponds.
 
 
 


 
 
 

Prof. dr Nenad Djajic
 
 

Born at Po`ega 31.07.1941; matriculated in Belgrade 1960; graduated from the Mechanical Engineering Faculty, Department of Thermal Engineering in 1965; Master's degree at Faculty for Applied Chemistry and Metallurgy, Department of Chemical Engineering in 1974;Ph.D.of technical science-Energy Management at the Faculty of Mining and Geology,all in Belgrade,in 1976.After graduation, worked and headed on Department of centralized heat and gas supply at the Mining Institute in Belgrade. From 1970, teaching "Thermodynamics" and "Heat Engines and Energy Plants" at the Faculty of Mining and Geology as the Assistant, Assistant Professor (1976). Associate Profesor (1982) and Full Professor (1988). From 1976, Head of Centre for Energy, Faculty of Mining and Geology. Participated and headed work on more than 150 studies and projects related to energy management, new and renewable sources of energy, oil and gas supply,rational use of energy, thermal engineering, centralized heat and gas supply and ecology. Published more than 355 papers in journals, proceedings and symposias (55 submitted to international meetings and journals ) autonomously or as a co-author.Author of three University books:"Heat Engines" ,"The Machines and Equipment for Drilling and Oil Production" and "Energy Sources and Plants"and two monographies "The Measure and Regulation of Natural Gas" and "The Production and Utilization of Geothermal Energy".Was present at the most of the World Energy Conferences, Oil and Gas Congresses.Has been in U.S.A., Canada, Poland, France, Great Britain, Germany, Austria, USSR and Hungary at specializations and study visits.
 
 

Present: Full University Professor,Head of Mechanical Department on Faculty of Mining and Geology,Belgrade;the full member of Yugoslav Academy of Engineering; the member of Energy Board of the Serbian Academy of Science and Art;the deputy secretary of Technical Depertment of the Serbian Society of Science;the Vice Chairman of the Yugoslav National Committee of the World Energy Council;the member of Federal Commission for Strategy of Energy FRY; the Chairman of Union of Mechanical and Electrical Engineers of Serbia.
 
 

Former: the member of the Executive Council and Chairman of Energy Board of the City of Belgrade; the member of the Committee for Energy and Industry of the Republic of Serbia;the member of Republic Council for Rational Use of Energy;the member of Republic Board for Energy Crisis;the member of the Scientific Council of Petroleum Engineering Society of the Yugoslav Academy of Science and Art;the member of the Federal Commission for New and Renewable sources of Energy and Federal Council for Ecology; the member of Commission of WEC for "New Energy Perspectives 2000-2020", the member of the Rural Networks FAO; the Secretary General of the Yugoslav National Committee of the WEC; the Chairman of the Serbian Society for Solar Energy.