Low-carbon power

The Hoover Dam when completed in 1936 was both the world's largest electric-power generating station and the world's largest concrete structure.

Hydroelectric plants have the advantage of being long-lived and many existing plants have operated for more than 100 years. Hydropower is also an extremely flexible technology from the perspective of power grid operation. Large hydropower provides one of the lowest cost options in today's energy market, even compared to fossil fuels and there are no harmful emissions associated with plant operation.[17] However, there are typically low greenhouse gas emissions with reservoirs, and possibly high emissions in the tropics.

Hydroelectric power is the world's largest low carbon source of electricity, supplying 15.6% of total electricity in 2019.[18] China is by far the world's largest producer of hydroelectricity in the world, followed by Brazil and Canada.

However, there are several significant social and environmental disadvantages of large-scale hydroelectric power systems: dislocation, if people are living where the reservoirs are planned, release of significant amounts of carbon dioxide and methane during construction and flooding of the reservoir, and disruption of aquatic ecosystems and birdlife.[19] There is a strong consensus now that countries should adopt an integrated approach towards managing water resources, which would involve planning hydropower development in co-operation with other water-using sectors.[17]

Blue Cherenkov radiation light being produced near the core of the Fission powered Advanced Test Reactor

Nuclear power, with a 10.6% share of world electricity production as of 2013, is the second largest low-carbon power source.[20]

Nuclear power, in 2010, also provided two thirds of the twenty seven nation European Union's low-carbon energy,[21] with some EU nations sourcing a large fraction of their electricity from nuclear power; for example France derives 79% of its electricity from nuclear. As of 2020 nuclear power provided 47% low-carbon power in the EU[22] with countries largely based on nuclear power routinely achieving carbon intensity of 30-60 gCO2eq/kWh.[23]

According to the IAEA and the European Nuclear Society, worldwide there were 68 civil nuclear power reactors under construction in 15 countries in 2013.[24][25] China has 29 of these nuclear power reactors under construction, as of 2013, with plans to build many more,[25][26] while in the US the licenses of almost half its reactors have been extended to 60 years,[27] and plans to build another dozen are under serious consideration.[28] There is also a considerable number of new reactors being built in South Korea, India, and Russia. Nuclear power's capability to add significantly to future low carbon energy growth depends on several factors, including the economics of new reactor designs, such as Generation III reactors, public opinion and national and regional politics.

The 104 U.S. nuclear plants are undergoing a Light Water Reactor Sustainability Program, to sustainably extend the life span of the U.S. nuclear fleet by a further 20 years. With further US power plants under construction in 2013, such as the two AP1000s at Vogtle Electric Generating Plant. However the Economics of new nuclear power plants are still evolving and plans to add to those plants are mostly in flux.[29]

In 2021 United Nations Economic Commission for Europe (UNECE) described nuclear power as important tool to mitigate climate change that has prevented 74 Gt of CO₂ emissions over the last half century, providing 20% of energy in Europe and 43% of low-carbon energy.[30]

The PS10 concentrates sunlight from a field of heliostats on a central tower.

Solar power is the conversion of sunlight into electricity, either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP). Concentrated solar power systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. Photovoltaics convert light into electric current using the photoelectric effect.[43]

Commercial concentrated solar power plants were first developed in the 1980s. The 354 MW SEGS CSP installation is the largest solar power plant in the world, located in the Mojave Desert of California. Other large CSP plants include the Solnova Solar Power Station (150 MW) and the Andasol solar power station (150 MW), both in Spain. The over 200 MW Agua Caliente Solar Project in the United States, and the 214 MW Charanka Solar Park in India, are the world's largest photovoltaic plants. Solar power's share of worldwide electricity usage at the end of 2014 was 1%.[44]

Geothermal electricity is electricity generated from geothermal energy. Technologies in use include dry steam power plants, flash steam power plants and binary cycle power plants. Geothermal electricity generation is used in 24 countries[45] while geothermal heating is in use in 70 countries.[46]

Current worldwide installed capacity is 10,715 megawatts (MW), with the largest capacity in the United States (3,086 MW),[47] Philippines, and Indonesia. Estimates of the electricity generating potential of geothermal energy vary from 35 to 2000 GW.[46]

Geothermal power is considered to be sustainable because the heat extraction is small compared to the Earth's heat content.[48] The emission intensity of existing geothermal electric plants is on average 122 kg of CO
₂ per megawatt-hour (MW·h) of electricity, a small fraction of that of conventional fossil fuel plants.[49]

Tidal power is a form of hydropower that converts the energy of tides into electricity or other useful forms of power. The first large-scale tidal power plant (the Rance Tidal Power Station) started operation in 1966. Although not yet widely used, tidal power has potential for future electricity generation. Tides are more predictable than wind energy and solar power.

Carbon capture and storage captures carbon dioxide from the flue gas of power plants or other industry, transporting it to an appropriate location where it can be buried securely in an underground reservoir. While the technologies involved are all in use, and carbon capture and storage is occurring in other industries (e.g., at the Sleipner gas field), no large scale integrated project has yet become operational within the power industry.

Improvements to current carbon capture and storage technologies could reduce CO₂ capture costs by at least 20-30% over approximately the next decade, while new technologies under development promise more substantial cost reduction.[50]

Greenhouse gas emissions by sector. See World Resources Institute for detailed breakdown

The Intergovernmental Panel on Climate Change stated in its first working group report that "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations, contribute to climate change.[51]

As a percentage of all anthropogenic greenhouse gas emissions, carbon dioxide (CO₂) accounts for 72 percent (see Greenhouse gas), and has increased in concentration in the atmosphere from 315 parts per million (ppm) in 1958 to more than 375 ppm in 2005.[52]

Emissions from energy make up more than 61.4 percent of all greenhouse gas emissions.[53] Power generation from traditional coal fuel sources accounts for 18.8 percent of all world greenhouse gas emissions, nearly double that emitted by road transportation.[53]

Estimates state that by 2020 the world will be producing around twice as much carbon emissions as it was in 2000.[54]

The European Union hopes to sign a law mandating net-zero greenhouse gas emissions in the coming year for all 27 countries in the union.

World CO₂ emissions by region

World energy consumption is predicted to increase from 123,000 TWh (421 quadrillion BTU) in 2003 to 212,000 TWh (722 quadrillion BTU) in 2030.[55] Coal consumption is predicted to nearly double in that same time.[56] The fastest growth is seen in non-OECD Asian countries, especially China and India, where economic growth drives increased energy use.[57] By implementing low-carbon power options, world electricity demand could continue to grow while maintaining stable carbon emission levels.

In the transportation sector there are moves away from fossil fuels and towards electric vehicles, such as mass transit and the electric car. These trends are small, but may eventually add a large demand to the electrical grid.

Domestic and industrial heat and hot water have largely been supplied by burning fossil fuels such as fuel oil or natural gas at the consumers' premises. Some countries have begun heat pump rebates to encourage switching to electricity, potentially adding a large demand to the grid.[58]

Coal-fired power plants are losing market share compared to low carbon power, and any built in the 2020s risk becoming stranded assets[2] or stranded costs, partly because their capacity factors will decline.[59]

Investment in low-carbon power sources and technologies is increasing at a rapid rate. Zero-carbon power sources produce about 2% of the world's energy, but account for about 18% of world investment in power generation, attracting $100 billion of investment capital in 2006.[60]