Geothermal energy is the thermal energy in the Earth's crust which originates from the formation of the planet and from radioactive decay of materials. The high temperature and pressure in Earth's interior cause some rock to melt and solid mantle to behave plastically. This results in parts of the mantle convecting upward since it is lighter than the surrounding rock. Temperatures at the core–mantle boundary can reach over 4000 °C (7200 °F).
The net capacity factor is the unitless ratio of actual electrical energy output over a given period of time to the theoretical maximum electrical energy output over that period. The theoretical maximum energy output of a given installation is defined as that due to its continuous operation at full nameplate capacity over the relevant period. The capacity factor can be calculated for any electricity producing installation, such as a fuel consuming power plant or one using renewable energy, such as wind or the sun. The average capacity factor can also be defined for any class of such installations, and can be used to compare different types of electricity production.
Renewable energy in Germany is mainly based on wind and biomass, plus solar and hydro. Germany had the world's largest photovoltaic installed capacity until 2014, and as of 2021 it has over 58 GW. It is also the world's third country by installed total wind power capacity, 64 GW in 2021 and second for offshore wind, with over 7 GW. Germany has been called "the world's first major renewable energy economy".
Renewable energy commercialization involves the deployment of three generations of renewable energy technologies dating back more than 100 years. First-generation technologies, which are already mature and economically competitive, include biomass, hydroelectricity, geothermal power and heat. Second-generation technologies are market-ready and are being deployed at the present time; they include solar heating, photovoltaics, wind power, solar thermal power stations, and modern forms of bioenergy. Third-generation technologies require continued R&D efforts in order to make large contributions on a global scale and include advanced biomass gasification, hot-dry-rock geothermal power, and ocean energy. As of 2012, renewable energy accounts for about half of new nameplate electrical capacity installed and costs are continuing to fall.
Iceland is a world leader in renewable energy. 100% of Iceland's electricity grid is produced from renewable resources. In terms of total energy supply, 85% of the total primary energy supply in Iceland is derived from domestically produced renewable energy sources. Geothermal energy provided about 65% of primary energy in 2016, the share of hydropower was 20%, and the share of fossil fuels was 15%.
Renewable energy in the United Kingdom contributes to production for electricity, heat, and transport.
A feed-in tariff is a policy mechanism designed to accelerate investment in renewable energy technologies by offering long-term contracts to renewable energy producers. This means promising renewable energy producers an above-market price and providing price certainty and long-term contracts that help finance renewable energy investments. Typically, FITs award different prices to different sources of renewable energy in order to encourage development of one technology over another. For example, technologies such as wind power and solar PV are awarded a higher price per kWh than tidal power. FITs often include a "degression": a gradual decrease of the price or tariff in order to follow and encourage technological cost reductions.
Geothermal power is electrical power generated from geothermal energy. Technologies in use include dry steam power stations, flash steam power stations and binary cycle power stations. Geothermal electricity generation is currently used in 26 countries, while geothermal heating is in use in 70 countries.
Nicaragua is the country in Central America with the lowest electricity generation, as well as the lowest percentage of population with access to electricity. The unbundling and privatization process of the 1990s did not achieve the expected objectives, resulting in very little generation capacity added to the system. This, together with its high dependence on oil for electricity generation, led to an energy crisis in 2006 from which the country has not fully recovered yet.
Geothermal power is very cost-effective in the Great Rift Valley of Kenya, East Africa. As of 2023, Kenya has 891.8 MW of installed geothermal capacity. Kenya was the first African country to build geothermal energy sources. The Kenya Electricity Generating Company, which is 74% state-owned, has built several plants to exploit the Olkaria geothermal resource; Olkaria I, Olkaria II, Olkaria IV, Olkaria V, and Wellhead generation plants, with a third private plant Olkaria III. Additionally, a pilot wellhead plant of 2.5 MW has been commissioned at Eburru and two small scale plants have been built by the Oserian Development Company to power their rose farm facilities with a total of 4 MW.
Renewable energy in Russia mainly consists of hydroelectric energy. In 2010, the country was the sixth largest producer of renewable energy in the world, although it was 56th when hydroelectric energy was not taken into account. Some 179 TWh of Russia's energy production came from renewable energy sources, out of a total economically feasible potential of 1823 TWh. 16% of Russia's electricity was generated from hydropower, and less than 1% was generated from all other renewable energy sources combined. Roughly 68% of Russia's electricity was generated from thermal power and 16% from nuclear power.
The electricity sector in Switzerland relies mainly on hydroelectricity, since the Alps cover almost two-thirds of the country's land mass, providing many large mountain lakes and artificial reservoirs suited for hydro power. In addition, the water masses drained from the Swiss Alps are intensively used by run-of-the-river hydroelectricity (ROR). With 9,052 kWh per person in 2008, the country's electricity consumption is relatively high and was 22% above the European Union's average.
Renewable energy has developed rapidly in Italy over the past decade and provided the country a means of diversifying from its historical dependency on imported fuels. Solar power accounted for around 8% of the total electric production in the country in 2014, making Italy the country with the highest contribution from solar energy in the world that year. Rapid growth in the deployment of solar, wind and bio energy in recent years lead to Italy producing over 40% of its electricity from renewable sources in 2014.
Most of Kenya's electricity is generated by renewable energy sources. Access to reliable, affordable, and sustainable energy is one of the 17 main goals of the United Nations’ Sustainable Development Goals. Development of the energy sector is also critical to help Kenya achieve the goals in Kenya Vision 2030 to become a newly industrializing, middle-income country. With an installed power capacity of 2,819 MW, Kenya currently generates 826 MW hydroelectric power, 828 geothermal power, 749 MW thermal power, 331 MW wind power, and the rest from solar and biomass sources. Kenya is the largest geothermal energy producer in Africa and also has the largest wind farm on the continent. In March 2011, Kenya opened Africa's first carbon exchange to promote investments in renewable energy projects. Kenya has also been selected as a pilot country under the Scaling-Up Renewable Energy Programmes in Low Income Countries Programme to increase deployment of renewable energy solutions in low-income countries. Despite significant strides in renewable energy development, about a quarter of the Kenyan population still lacks access to electricity, necessitating policy changes to diversify the energy generation mix and promote public-private partnerships for financing renewable energy projects.
Renewable energy in Taiwan contributed to 8.7% of national electricity generation as of end of 2013. The total installed capacity of renewable energy in Taiwan by the end of 2013 was 3.76 GW. As of 2020, the Taiwan government aims for a renewable share of 20% by 2025, with coal and gas providing the other 80%.
Renewable energy in Albania includes biomass, geothermal, hydropower, solar, and wind energy. Albania relies mostly on hydroelectric resources, therefore, it has difficulties when water levels are low. The climate in Albania is Mediterranean, so it possesses considerable potential for solar energy production. Mountain elevations provide good areas for wind projects. There is also potentially usable geothermal energy because Albania has natural wells.
There is enormous potential for renewable energy in Kazakhstan, particularly from wind and small hydropower plants. The Republic of Kazakhstan has the potential to generate 10 times as much power as it currently needs from wind energy alone. But renewable energy accounts for just 0.6 percent of all power installations. Of that, 95 percent comes from small hydropower projects. The main barriers to investment in renewable energy are relatively high financing costs and an absence of uniform feed-in tariffs for electricity from renewable sources. The amount and duration of renewable energy feed-in tariffs are separately evaluated for each project, based on feasibility studies and project-specific generation costs. Power from wind, solar, biomass and water up to 35 MW, plus geothermal sources, are eligible for the tariff and transmission companies are required to purchase the energy of renewable energy producers. An amendment that introduces and clarifies technology-specific tariffs is now being prepared. It is expected to be adopted by Parliament by the end of 2014. In addition, the World Bank's Ease of Doing Business indicator shows the country to be relatively investor-friendly, ranking it in 10th position for investor protection.
Renewable energy in South Africa is energy generated in South Africa from renewable resources, those that naturally replenish themselves—such as sunlight, wind, tides, waves, rain, biomass, and geothermal heat. Renewable energy focuses on four core areas: electricity generation, air and water heating/cooling, transportation, and rural energy services. The energy sector in South Africa is an important component of global energy regimes due to the country's innovation and advances in renewable energy. South Africa's greenhouse gas (GHG) emissions is ranked as moderate and its per capita emission rate is higher than the global average. Energy demand within the country is expected to rise steadily and double by 2025.
In Ukraine, the share of renewables within the total energy mix is less than 5%. In 2020 10% of electricity was generated from renewables; made up of 5% hydro, 4% wind, and 1% solar. Biomass provides renewable heat.
By the end of 2016 Austria already fulfilled their EU Renewables Directive goal for the year 2020. By 2016 renewable energies accounted to 33.5% of the final energy consumption in all sectors. The renewable energy sector is also accountable for hosting 41,591 jobs and creating a revenue of 7,219 million euros in 2016.
