Renewable Energies - Geothermal Energy

  RENEWABLE ENERGIES - GEOTHERMAL ENERGY page  2

  Ludmilla Deines  

  Content  

1.  Challenge and Objectives of this Essay  3

2.  Renewable Energies  6

2.1  Status and Perspectives  6

2.2  Global Potential of Renewable Energies  10

2.2.1  Solar Energy  10

2.2.2  Biomass  12

2.2.3  Wind Energy  12

2.2.4  Hydropower  13

3.  Geothermal Energy  13

3.1  History  14

3.2  The Nature of Geothermal Resources  15

3.3  Technologies  17

3.4  Potential and Utilization of Geothermal Energy  20

4.  Summary and Conclusion  22

5.  Appendix - Energy Units  25

6.  Bibliography  26

RENEWABLE ENERGIES - GEOTHERMAL ENERGY page 3 Ludmilla Deines

1. Challenge and Objectives of this Essay

Nowadays, it is unimaginable for people, at least in industrialized countries, not to have any access to energy sources. For the industry sector it is the basic precondition for its existence. For every little step within the production process, being the production of a good itself, the handling with raw materials or the transportation of the final product to the customer, plenty of energy is required. Private households also consume a lot of energy. We need energy for cooking, for washing, for cleaning and heating our homes, for watching television, for listening to the music, for being able to read a book after the sunset. But due to the global population growth, the available earth’s resources have come under enormous pressure to meet the humans’ energy needs (Pérez Latorre, 1999, p. 2). In the last 30 years the world’s population has grown by more than 30% (www.weltbevoelkerung.de *1+) and reached the present status of about 6.6 billion people (www.cia.gov [2]). The total energy consumption has even increased more quickly comparing to the number of people on the planet. It has just doubled between 1970 and 2000. Within a short time people have consumed a colossal part of precious natural resources which took millions of years to produce (BMU, Renewable Energies - Innovations for the future, 2006, p. 10). At the same time the population continues to grow and is estimated to reach about 9.1 billion people by the year 2050 (www.un.org [3]).

Figure 1: Development of the world population,

own graph, data based on United Nations, World Population Prospects: The 2006 Revision, 2007, http://esa.un.org/unpp/

RENEWABLE ENERGIES - GEOTHERMAL ENERGY page 4

Ludmilla Deines

As the supply of oil, gas, coal and uranium, so called classic energy resources, is quite limited, the increase of population could result in the energy supply shortfall with considerable economic and social consequences. But this is not the only problem. The reserves of fossil fuels are distributed unequally over the globe (BMU, Renewable Energies -Innovations for the future, 2006, p. 11). The high dependence of energy-hungry industrial countries from energy supplying countries can even lead to political conflicts, which already occurred in resent past.

Furthermore the use of these energy resources has significant environmental effects. The capacity of the environment to absorb the waste produced by the energy consumption is strictly limited, too. Moreover, these waste products not only damage the environment, but also are harmful to the human health (BMU, Renewable Energies - Innovations for the future, 2006, p. 12). For example the mining and enrichment of uranium produces radioactive isotopes contaminating areas including ground water, air and plants. As a result the whole ecosystem including humans is affected. There is also a lot of waste produced in the reactor core, for which there is no known way of a safety disposal. Handling of byproducts of nuclear energy is a big problem. But the danger of underestimating the given risk of accident which exists in spite of preventive measures should be taken into consideration, too. Some accidents at nuclear power plants already occurred in the past. The worst nuclear accident happened in 1986 in Chernobyl, former U.S.S.R. (today Ukraine), as the reactor at the power plant exploded, causing a great deal of environmental and health problems which are noticeable till this day (www.wagingpeace.org [4]). Thousands of people including children died and still suffer from the consequences of radiation. 350,000 citizens had to be evacuated. The consequences of the accident extended far beyond Ukraine and the year 1986 (BMU, Tschernobyl, Magazin zur Atompolitik, 2006, p. 2).

RENEWABLE ENERGIES - GEOTHERMAL ENERGY page 5

Ludmilla Deines

Figure 2: Contaminated areas due to the accident at nuclear power plant in Chernobyl

http://www.tagesschau.de/ausland/meldung121596.html

While an accident at a nuclear power plant would scare everyone, damages caused by accidents in the oil industry don’t shock the public any more, because they occur more often and even became quite normal. However, the consequences of such accidents may last for years. For example in 1989 the oil tanker Exxon Valdez struck a riff in Alaska’s Prince William Sound and precipitated an environmental disaster. 257,000 barrels of oil leaked and polluted the coast area. Thousands of birds, fish and mammals died. In spite of billions of dollars spent on the cleanup of the area, today, almost 19 years later, there are still oiled beaches and moribund animals (www.evostc.state.ak.us [5], www.greenpeace.de [6]).

Apart from the accidents relating to the oil production and the oil transportation, there is another type of waste produced by the consumption of oil. The effect of carbon dioxide, a by-product of oil consumption, is considered to be the major factor of causing climate change.

The challenge of this essay is to analyse, whether and if so which alternative energy sources are to be considered as an answer to the problems mentioned above. Thereby I want to examine sustainable energy resources in order to find out, whether their utilization make sense politically, economically and environmentally. First I will provide general information

RENEWABLE ENERGIES - GEOTHERMAL ENERGY page 6

Ludmilla Deines

about renewable energies and give an overview of main renewable energy sources. Finally I will focus on geothermal energy, analysing this energy source more detailed.

2. Renewable Energies

2.1 Status and Perspectives

Renewable energy is a generic term for a wide range of naturally occurring energy sources, which are able to replenish themselves (European Commission, Renewable Energy Sources -Sectoral Report 1995-97, 1998, p. 6). As a result of my analysis I drew a conclusion, it is beyond question that the use of renewables considerably contributes to the solution of the problems exemplified above. Their use makes good political and economical sense. Due to the fact that the renewable energies are endless, they add to the secure energy supply and help to prevent resource conflicts. Renewable energy resources are in general locally available and contribute to the independence from the oil supplying countries. Of course there are also other ways to become independent from the powerful suppliers of fossil energy. Some economies try to become independent from the oil and gas suppliers by investing in nuclear energy in their countries. So does for example the government of Belarus, initiating a construction of a new nuclear power plant, which should operate at full capacity as from 2020 (Südkurier, 16.01.2008). The problem of dependency may be solved by this action, but other problems will be created. The effects on the environment and additional risks for the whole ecosystem of the country and large areas around are grave.

In contrast the use of sustainable energy resources not only reduces the dependency from fossil energy suppliers, but also makes it possible to limit the production of harmful pollutants and to contribute to climate protection (BMU, Renewable Energies - Innovations for the future, 2006, p. 20). Though the use of renewable energies is not fully free of pollutants, it causes by far less damage than the use of fossil energies. Replacing one tonne of oil equivalent (toe) of primary fossil fuel by renewable energies, the emission of CO 2 is

RENEWABLE ENERGIES - GEOTHERMAL ENERGY page 7

Ludmilla Deines

reduced by 2.3 tonnes (European Commission, Renewable Energy Systems - New Solutions in Energy Supply, 1999, p. 9).

The next point is, the renewable energy sources are simply to access for large population groups (BMU, Renewable Energies - Innovations for the future, 2006, p. 20). So, the sun has been supplying energy to the whole earth for billions of years and will continue to do so in the future. Plants grow and produce biomass by using the energy from the sun. Furthermore the sun drives the weather and thereby creates the best conditions for using wind energy and hydropower (BMU, Renewable Energies - Innovations for the future, 2006, p. 17). Finally, the nature of our planet makes it possible to use geothermal energy as another form of renewable energy.

In spite of the obvious benefits provided by renewable energies, the corresponding industry is still in building up. The total consumption of renewable energies in the year 2005 amounted only 13.3% of the world’s total energy consumption (BMU, Renewable Energies -Innovations for the future, 2006, p. 51).

Figure 3: Structure of global primary energy consumption,

BMU, Renewable Energies - Innovations for the future, 2006, p. 51

In Germany the renewable energies met 4.6% of the primary energy demand in 2005. Even though this amount seems to be very small, the contribution of renewable energies to

RENEWABLE ENERGIES - GEOTHERMAL ENERGY page 8

Ludmilla Deines

Germany’s energy supply has almost doubled between 2000 and 2005 (BMU, Renewable Energies - Innovations for the future, 2006, p. 37). Meanwhile the renewable energy sector became an important economic factor. The domestic turnover in the year 2006 amounted to around 22.9 billion euro. The largest turnover was generated in the sector of biomass use, followed by the use of solar- and wind power. Linked to this, there is a significant growth in employment. In 2006 the renewable energies sector created around 214,000 jobs in Germany (www.bmu.de [7]). On the other side this development implies a danger for employment in the conventional energy industry. Moreover, the investment and production costs of renewable energies are still higher than these of the conventional energies and burden the budget of the consumers (BMU, Renewable Energies - Innovations for the future, 2006, p. 39).

It is common, that the market introduction phase goes along with high expenses. Therefore, in order to give the renewable energy a go, the renewable energy market is supported by the German Federal Government, until it will become competitive. The German government has ambitious goals regarding renewable energies. To name just one of those: until 2050 renewable energy should meet 50% of the German energy demand (BMU, Renewable Energies - Innovations for the future, 2006, p. 44). There are several instruments and market stimulation programmes in Germany and the European Union to support the production and consumption of renewable energy. A reliable source to promote renewable energy is the Renewable Energy Sources Act (EEG, Erneuerbare-Energien-Gesetz), which was implemented in Germany in the year 2000 and modernized in 2004. The act aims to increase the share of renewables in the electricity production in Germany. It gives the priority to electricity from renewable energy sources and support energy utilities, which supply the grid with electricity from renewables (www.bmu.de [8]; BMU, EEG - The Renewable Energy Sources Act, 2007, p. 5). Furthermore there are several loan programmes, handled by the Reconstruction Loan Corporation (Kreditanstalt für Wiederaufbau, KfW), which are aimed to support the financing of renewable energies. There are also reimbursements of consulting costs for energy advisory services for old residential buildings. Regarding the transportation sector the renewable energies are also strongly supported, especially biofuels are favoured by the mineral oil tax (BMU, Renewable Energies - Innovations for the future, 2006, p. 42).