Geothermal Energy

The renewable energy resource which at present is the least developed is geothermal heat. Deep-well geothermal ener­gy makes use either of hot water from the depths of the earth, or it utilizes hydraulic stimulation to inject water in­to hot, dry rock strata (hot-dry rock process), with wells of up to 5 km deep (see the chapter “Energy from the Depths”). At temperatures over 100 °C, electric power can also be produced – in Germany for example at the Neustadt – Glewe site in Mecklenburg-Vorpommern. Favorable regions with high thermal gradients are in particular the North Ger­man Plain, the North Alpine Molasse Basin, and the Upper Rhine Graben.

Geothermal heat has the advantage that it is available around the clock. Nevertheless, the use of geothermal heat and power production is still in its infancy. Especially the exploitation of deep-well geothermal energy is technically challenging and still requires intense research and devel­opment. Near-surface geothermal energy is more highly de­veloped; heat pumps have long been in use.

The exploitation of deep-well and near-surface geot­hermal heat more than tripled in the decade from 2000 (1.7 TWh) to 2010 (5.6 TWh). If and when it becomes possible to utilize geothermal energy on a major scale, then its con­stancy and reliability will make a considerable contribution to the overall energy supply. Its long-term potential in Ger­many is estimated to be 90 TWh/year for electric power generation and 300 TWh/year for heating.

The Window of Opportunity

How will energy supplies in Germany develop in the future? Will all the renewable energy source options play a role, and if so, to what extent? The resolution of the federal govern­ment on June 6, 2011 contains the following elements for an energy turnaround in Germany:

• An exit strategy for nuclear power in Germany by the end of 2022;

• Continuous development of the use of renewable en­ergy sources;

• Modernization and further development of the electric power grid;

• Energy conservation and an increase in efficiency in all areas concerning energy;

• Attaining the challenging climate protection goals and thereby a clear-cut reduction in the consumption of fos­sil fuels.

The German Federal government, with its energy turnaround (Energiewende) package adopted on June 6th, 2011 and the amendment of the Renewable Energy Act, is pursuing the goals set out here: The fraction of renewable energy sources in electric power generation are to increase as follows:

– by 2020 at the latest up to at least 35 %

– by 2030 at the latest: up to at least 50 %

– by 2040 at the latest: up to at least 65 %

– by 2050 at the latest: up to at least 80 %

Подпись: - by 2020: 18 % (corresponds to the EU directive; see above) - by 2030: 30 % - by 2040: 45 % - by 2050: 60 % Furthermore, by 2020 their contribution to space heating in total should increase to 14 % and their contribution to energy use in the transportation sector to 10 %. The Federal cabinet also enacted additional goals in Berlin on June 6th, 2011, to which the development of renewable energy sources makes essential contributions. The German emissions of greenhouse gases are to be decreased by 40 % by 2020, based on the reference year 1990, and by 80 to 95 % by 2050. Consumption of electric power is to decrease by 10 % up to 2020 and by 25 % up to 2050; consumption of all primary energies by 20 % up to 2020 and by 50 % up to 2050. Подпись:The goals for growth of the fraction of renewable energy sources in overall energy consumption (electric power, heating/cooling, transportation) are:

ful effects on the climate, the beneficial aspects of renew­able energy sources will presumably become more and more apparent [16].