by Graeme » Sun 13 Mar 2005, 03:02:48
I copied this from the IGA newsletter June 2003:
Status of Geothermal Energy Amongst the World´s Energy Sources (Part I)Ingvar B. Fridleifsson, United Nations University
- Geothermal Training Programme, Orkustofnun, National Energy Authority, Iceland
Abstract: The world primary energy consumption is about 400 EJ/year, mostly provided by fossil fuels (80%). The renewables collectively provide 14% of the primary energy, in the form of traditional biomass (10%), large (>10MW) hydropower stations (2%), and the new renewables (2%). Nuclear energy provides 6%. The World Energy Council expects the world primary energy consumption to have grown by 50-275% in 2050 depending on different scenarios. The renewable energy sources are expected to provide 20-40% of the primary energy in 2050 and 30-80% in 2100. The technical potential of the renewables is estimated 7600 EJ/year, and thus certainly sufficiently large to meet future world energy requirements.
Of the total electricity production from renewables of 2826 TWh in 1998, 92% came from hydropower, 5.5% from biomass, 1.6% from geothermal and 0.6% from wind. Solar electricity contributed 0.05% and tidal 0.02%. The electricity cost is 2-10 US/kWh for geothermal and hydro, 5-13 US/kWh for wind, 5-15 US/kWh for biomass, 25-125 US/kWh for solar photovoltaic and 12-18 US/kWh for solar thermal electricity. Biomass constitutes 93% of the total direct heat production from renewables, geothermal 5%, and solar heating 2%. Heat production from renewables is commercially competitive with conventional energy sources. Direct heat from biomass costs 1-5 US/kWh, geothermal 0.5-5 US/kWh, and solar heating 3-20 US/kWh.
Keywords: geothermal, electricity, direct use, comparison of renewables, energy prices.
1. Introduction: With increasing awareness of the detrimental effects of the burning of fossil fuels on the environment, there has been an increasing interest world wide in the use of clean and renewable energy sources. It is important for the proponents of renewable energy sources to be aware of the outlines of the world energy use. The present paper starts with a description of recent energy forecasts for the world in the new century and the increasing role that renewable energy sources are expected to play in the world energy mix. The forecasts referred to here have been initiated by the World Energy Council. The present use of energy sources is summarised. A comparison is made of geothermal
energy with other renewable energy sources based on data presented in the World Energy Assessment report [1] prepared by the United Nations Development Programme, the United Nations Department of Economic and Social Affairs, and the World Energy Council. The present paper is largely based on two review papers recently published by the author [2], [3].
2. World energy forecasts: Amongst the top priorities for the majority of the world´s population is access to sufficient affordable energy. There is a very limited equity in the energy use in the different parts of the world. Some 70% of the world´s population lives at per capita energy consumption level onequarter of that of W-Europe, and one-sixth of that of the USA [4]. Two billion people, a third of the world´s population, have no access to modern energy services. A key issue to improve the standard of living of the poor is to make clean energy available to them at prices they can cope with. World population is expected to double by the end of the 21st century. To provide sufficient commercial energy (not to mention clean energy) to the people of all continents is an enormous task.
The World Energy Council (WEC) has presented several scenarios for meeting the future energy requirements with varying emphasis on economic growth rates, technological progress, environmnetal protection and international equity. All the scenarios provide for substantial social and economic development, particularly in the developing countries. They provide for improved energy efficiencies and environmental compatibility. During 1990-2050, the primary energy consumption is expected to increase by some 50% according to the most environmentally conscious scenario and by some 275% according to the highest growth rate scenario. In the enviornmental scenario, the carbon emissions are expected to decrease slightly from 1990 levels. The high growth rate scenario is expected to lead to a doubling of the carbon emissions [5].
The scarcity of energy resources forecasted in the 1970s did not occur. With technological and economic development, estimates of the ultimately available energy resource base continue to increase. Economic development over the next century will apparently not be constrained by geological resources. Environmental concerns, financing, and technological constrains appear more likely to limit future development.
In all WEC´s scenarios, the peak of the fossil fuel era has already passed. Oil and gas are expected to continue to be important sources of energy in all cases, but the role of renewable energy sources and nuclear energy vary highly in the scenarios and the level to which these energy sources replace coal. In all the scenarios, the renewables are expected to become very significant contributors to the world primary energy consumption, providing 20-40% of the primary energy in 2050 and 30-80% in 2100. They are expected to cover a large part of the increase in the energy consumption and to replace coal.
It is a very legitimate question to ask whether these scenarios are realistic. Table IV shows the technical potential of renewable energy resources. The technical potential is the yearly availability of the renewable resources.
There is no question that the technical potential of the renewables is sufficiently large to meet future world energy requirements. The question is, however, how large a part of the technical potential can be harnessed in an economical, environmentally and socially acceptable way. This will probably vary between the energy sources. It is worth noting, however, that the present annual consumption of primary energy in the world is about 400 EJ (Table IV).
References
1. WEA(2000). World Energy Assessment: energy and the challenge of sustainability. Prepared by UNDP, UNDESA and the World Energy Council. United Nations Development Programme, New York, 508 pp.
2. Fridleifsson, I.B. (2001). Geothermal energy for the benefit of the people. Renewable and Sustainable Energy Reviews, 5, p. 299-312.
3. Fridleifsson, I.B. (2002). Energy requirements for the new millennium. In: Human development and the environment: Challenges for the United Nations in the new millennium, p 220- 233. United Nations University Press, Tokyo.
4. WEC (1993). Energy for Tomorrow's World, St. Martin's Press, USA, 320 pp.
5. Nakicenovic, N., A. Grabler, and A. McDonald, (editors) 1998. Global Energy Perspectives, Cambridge Univ. Press, 299 pp.
Hydropower 50
Biomass 276
Solar energy 1575
Wind energy 640
Geothermal energy 5000
TOTAL 7600
Table IV. Technical potential of renewable energy sources
Source: World Energy Assessment [1].
My question is: Why doesn't ASPO consider geothermal as a renewable energy source?