Survey of Energy Resources 2007
Geothermal - Conclusions
One of the major concerns of mankind today is the ever-increasing emissions of greenhouse gases into the atmosphere and the threat of global warming. There is an international acceptance that a continuation of the present way of producing most of the energy needed - by burning fossil fuels - will bring about significant climate change, global warming, rises in sea level, floods, droughts, deforestation, and extreme weather conditions. The sad fact is that the poorest people in the world, who have done nothing to bring on the changes, will suffer the most. One of the key solutions to avoid these difficulties is to reduce the use of fossil fuels and increase the sustainable use of renewable energy sources. In many parts of the world, geothermal energy can play an important role in this respect.
In the direct use sector, the potential for geothermal is very large, as space heating and water heating are a significant part of the energy budget in large parts of the world. In industrialised countries, 35-40% of total primary energy consumption is used in buildings. In Europe, 30% of energy use is for space and water heating alone, representing 75% of total building energy use. The recent decision by the Commission of the European Union to reduce greenhouse gas emissions in the member countries by 20% by 2020 compared to 1990 implies a significant acceleration in the use of renewable energy resources. Many EU countries already have a considerable number of geothermal installations. The same applies to the USA where the use of ground-source heat pumps is widespread, both for space heating and cooling. The largest potential is, however, in China. Due to the geological conditions, there are widespread low-temperature geothermal resources in most provinces of China, which are already widely used for space heating, balneology, fish farming and greenhouses during the cold winter months, and also for tap water in the summer.
In the electricity sector, the geographical distribution of suitable geothermal fields is more restricted and mainly confined to countries or regions on active plate boundaries or with active volcanoes. As mentioned earlier, geothermal power stations provide about 12% of the total electricity generation of Costa Rica, El Salvador, Guatemala and Nicaragua. Hydro stations provide 48% of their electricity, and wind energy 1%. With an interconnected grid, it would be easy to provide all the electricity for the four by renewable energy.
With its large untapped geothermal resources and significant experience in the technology, as well as in hydro development, Central America may become an international example of how to reduce the overall emissions of greenhouse gases over a large area. Similar development can be foreseen in the East African Rift Valley, as well as in several other countries and regions rich in high-temperature geothermal resources.
It is very important for the proponents of the various types of renewable energy to work together in order to find the optimal use of energy resources.
Ingvar B. Fridleifsson
United Nations University Geothermal Training Programme,
International Geothermal Association