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75-422: (Redirected from New Energy ) New energy may refer to: Alternative energy , any energy source other than fossil fuels , which include: Renewable energy , energy from resources which are naturally replenished on a human timescale, such as sunlight, wind, surface water, tides, wind waves and geothermal heat Nuclear power , the atomic energy harvested from

150-463: A faster rate than they are consumed". Solar power , wind power , hydroelectricity , geothermal energy, and biomass are widely agreed to be the main types of renewable energy. Renewable energy often displaces conventional fuels in four areas: electricity generation , hot water / space heating , transportation , and rural (off-grid) energy services. Although almost all forms of renewable energy cause much fewer carbon emissions than fossil fuels,

225-465: A fluctuating nature, such as wind power and solar power. In contrast, controllable renewable energy sources include dammed hydroelectricity , bioenergy , or geothermal power . Renewable energy systems have rapidly become more efficient and cheaper over the past 30 years. A large majority of worldwide newly installed electricity capacity is now renewable. Renewable energy sources, such as solar and wind power, have seen significant cost reductions over

300-868: A fuel directly (e.g. wood logs), the terms biomass and biofuel have sometimes been used interchangeably. However, the term biomass usually denotes the biological raw material the fuel is made of. The terms biofuel or biogas are generally reserved for liquid or gaseous fuels respectively. Wood and wood residues is the largest biomass energy source today. Wood can be used as a fuel directly or processed into pellet fuel or other forms of fuels. Other plants can also be used as fuel, for instance maize , switchgrass , miscanthus and bamboo . The main waste feedstocks are wood waste, agricultural waste , municipal solid waste , and manufacturing waste . Upgrading raw biomass to higher grade fuels can be achieved by different methods, broadly classified as thermal, chemical, or biochemical: Thermal conversion processes use heat as

375-437: A given time. Solar energy can only be captured during the day, and ideally in cloudless conditions. Wind power generation can vary significantly not only day-to-day, but even month-to-month. This poses a challenge when transitioning away from fossil fuels: energy demand will often be higher or lower than what renewables can provide. Both scenarios can cause electricity grids to become overloaded, leading to power outages . In

450-952: A large portion of the total, such as Kenya (43%) and Indonesia (5%). Technical advances may eventually make geothermal power more widely available. For example, enhanced geothermal systems involve drilling around 10 kilometres (6.2 mi) into the Earth, breaking apart hot rocks and extracting the heat using water. In theory, this type of geothermal energy extraction could be done anywhere on Earth. There are also other renewable energy technologies that are still under development, including enhanced geothermal systems , concentrated solar power , cellulosic ethanol , and marine energy . These technologies are not yet widely demonstrated or have limited commercialization. Some may have potential comparable to other renewable energy technologies, but still depend on further breakthroughs from research, development and engineering. Enhanced geothermal systems (EGS) are

525-638: A more energy-dense biofuel like ethanol. Wood is the most significant biomass energy source as of 2012 and is usually sourced from a trees cleared for silvicultural reasons or fire prevention . Municipal wood waste – for instance, construction materials or sawdust – is also often burned for energy. The biggest per-capita producers of wood-based bioenergy are heavily forested countries like Finland, Sweden, Estonia, Austria, and Denmark. Bioenergy can be environmentally destructive if old-growth forests are cleared to make way for crop production. In particular, demand for palm oil to produce biodiesel has contributed to

600-506: A new type of geothermal power which does not require natural hot water reservoirs or steam to generate power. Most of the underground heat within drilling reach is trapped in solid rocks, not in water. EGS technologies use hydraulic fracturing to break apart these rocks and release the heat they contain, which is then harvested by pumping water into the ground. The process is sometimes known as "hot dry rock" (HDR). Unlike conventional geothermal energy extraction, EGS may be feasible anywhere in

675-409: A range of construction strategies and technologies that aim to optimize the distribution of solar heat in a building. Examples include solar chimneys , orienting a building to the sun, using construction materials that can store heat , and designing spaces that naturally circulate air . From 2020 to 2022, solar technology investments almost doubled from USD 162 billion to USD 308 billion, driven by

750-416: A renewable power source , although this is controversial. Renewable energy installations can be large or small and are suited for both urban and rural areas. Renewable energy is often deployed together with further electrification . This has several benefits: electricity can move heat and vehicles efficiently and is clean at the point of consumption. Variable renewable energy sources are those that have

825-430: A significant climate change mitigation potential if implemented correctly. Most of the recommended pathways to limit global warming include substantial contributions from bioenergy in 2050 (average at 200 EJ). The IPCC Sixth Assessment Report defines bioenergy as "energy derived from any form of biomass or its metabolic by-products". It goes on to define biomass in this context as "organic material excluding

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900-702: A variety of environmental conditions and perform more efficiently allowing a greater proportion of photon energy to end up in the storage compounds, i.e., carbohydrates (rather than building and sustaining living cells). However, prominent research faces hurdles, Sun Catalytix a MIT spin-off stopped scaling up their prototype fuel-cell in 2012 because it offers few savings over other ways to make hydrogen from sunlight. Most new renewables are solar, followed by wind then hydro then bioenergy. Investment in renewables, especially solar, tends to be more effective in creating jobs than coal, gas or oil. Worldwide, renewables employ about 12 million people as of 2020, with solar PV being

975-456: Is thermal energy (heat) extracted from the Earth's crust . It originates from several different sources , of which the most significant is slow radioactive decay of minerals contained in the Earth's interior , as well as some leftover heat from the formation of the Earth . Some of the heat is generated near the Earth's surface in the crust, but some also flows from deep within the Earth from

1050-471: Is a more economical means of long-term renewable energy storage, in terms of capital expenditures compared to pumped hydroelectric or batteries. Solar power produced around 1.3 terrawatt-hours (TWh) worldwide in 2022, representing 4.6% of the world's electricity. Almost all of this growth has happened since 2010. Solar energy can be harnessed anywhere that receives sunlight; however, the amount of solar energy that can be harnessed for electricity generation

1125-537: Is a technology for generating electricity by mixing fresh water and salty sea water in large power cells. Most marine energy harvesting technologies are still at low technology readiness levels and not used at large scales. Tidal energy is generally considered the most mature, but has not seen wide deployment. The world's largest tidal power station is on Sihwa Lake , South Korea, which produces around 550 gigawatt-hours of electricity per year. Earth emits roughly 10 W of infrared thermal radiation that flows toward

1200-419: Is about 800 times denser than air , even a slow flowing stream of water, or moderate sea swell , can yield considerable amounts of energy. Water can generate electricity with a conversion efficiency of about 90%, which is the highest rate in renewable energy. There are many forms of water energy: Much hydropower is flexible, thus complementing wind and solar. In 2021, the world renewable hydropower capacity

1275-940: Is also agreement that local environmental impacts can be problematic. For example, increased biomass demand can create significant social and environmental pressure in the locations where the biomass is produced. The impact is primarily related to the low surface power density of biomass. The low surface power density has the effect that much larger land areas are needed in order to produce the same amount of energy, compared to for instance fossil fuels . Long-distance transport of biomass have been criticised as wasteful and unsustainable, and there have been protests against forest biomass export in Sweden and Canada. In 2020 bioenergy produced 58 EJ ( exajoules ) of energy, compared to 172 EJ from crude oil , 157 EJ from coal, 138 EJ from natural gas , 29 EJ from nuclear, 16 EJ from hydro and 15 EJ from wind , solar and geothermal combined. Most of

1350-429: Is being developed as a feedstock for ethanol production, and biodiesel can be produced from left-over food products like vegetable oils and animal fats. The surface power production densities of a crop will determine how much land is required for production. The average lifecycle surface power densities for biomass, wind, hydro and solar power production are 0.30 W/m , 1 W/m , 3 W/m and 5 W/m , respectively (power in

1425-525: Is common in Iceland, or to generate electricity. At smaller scales, geothermal power can be generated with geothermal heat pumps , which can extract heat from ground temperatures of under 30 °C (86 °F), allowing them to be used at relatively shallow depths of a few meters. Electricity generation requires large plants and ground temperatures of at least 150 °C (302 °F). In some countries, electricity produced from geothermal energy accounts for

1500-465: Is different from Wikidata All article disambiguation pages All disambiguation pages Alternative energy Renewable energy (or green energy ) is energy from renewable natural resources that are replenished on a human timescale . The most widely used renewable energy types are solar energy , wind power , and hydropower . Bioenergy and geothermal power are also significant in some countries. Some also consider nuclear power

1575-401: Is enough fuel for breeder reactors to satisfy the world's energy needs for 5 billion years at 1983's total energy consumption rate, thus making nuclear energy effectively a renewable energy. In addition to seawater the average crustal granite rocks contain significant quantities of uranium and thorium with which breeder reactors can supply abundant energy for the remaining lifespan of the sun on

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1650-459: Is harvested unsustainably. Bioenergy feedstocks typically require significant amounts of energy to harvest, dry, and transport; the energy usage for these processes may emit greenhouse gases. In some cases, the impacts of land-use change , cultivation, and processing can result in higher overall carbon emissions for bioenergy compared to using fossil fuels. Bioenergy can either mitigate (i.e. reduce) or increase greenhouse gas emissions . There

1725-518: Is influenced by weather conditions , geographic location and time of day. There are two mainstream ways of harnessing solar energy: solar thermal , which converts solar energy into heat; and photovoltaics (PV), which converts it into electricity. PV is far more widespread, accounting for around two thirds of the global solar energy capacity as of 2022. It is also growing at a much faster rate, with 170 GW newly installed capacity in 2021, compared to 25 GW of solar thermal. Passive solar refers to

1800-453: Is known as bioenergy with carbon capture and storage (BECCS) and can result in net carbon dioxide removal from the atmosphere. However, BECCS can also result in net positive emissions depending on how the biomass material is grown, harvested, and transported. Deployment of BECCS at scales described in some climate change mitigation pathways would require converting large amounts of cropland. Bioenergy with carbon capture and storage (BECCS)

1875-694: Is made by fermentation , mostly from carbohydrates produced in sugar or starch crops such as corn , sugarcane , or sweet sorghum . Bioethanol is widely used in the United States and in Brazil . Biodiesel is produced from the oils in for instance rapeseed or sugar beets and is the most common biofuel in Europe. Second-generation biofuels (also called "advanced biofuels") utilize non-food -based biomass sources such as perennial energy crops and agricultural residues/waste. The feedstock used to make

1950-460: Is more valuable than VRE countries with large hydroelectric developments such as Canada and Norway are spending billions to expand their grids to trade with neighboring countries having limited hydro. Biomass is biological material derived from living, or recently living organisms. Most commonly, it refers to plants or plant-derived materials. As an energy source, biomass can either be used directly via combustion to produce heat, or converted to

2025-596: Is not possible to use or store excess electricity. Electrical energy storage is a collection of methods used to store electrical energy. Electrical energy is stored during times when production (especially from intermittent sources such as wind power , tidal power , solar power ) exceeds consumption, and returned to the grid when production falls below consumption. Pumped-storage hydroelectricity accounts for more than 85% of all grid power storage . Batteries are increasingly being deployed for storage and grid ancillary services and for domestic storage. Green hydrogen

2100-520: Is often associated with unsustainable deforestation . As part of the global effort to limit climate change , most countries have committed to net zero greenhouse gas emissions . In practice, this means phasing out fossil fuels and replacing them with low-emissions energy sources. This much needed process, coined as "low-carbon substitutions" in contrast to other transition processes including energy additions, needs to be accelerated multiple times in order to successfully mitigating climate change. At

2175-477: Is that the heated water can be stored until it is needed, eliminating the need for a separate energy storage system. Solar thermal power can also be converted to electricity by using the steam generated from the heated water to drive a turbine connected to a generator. However, because generating electricity this way is much more expensive than photovoltaic power plants, there are very few in use today. Humans have harnessed wind energy since at least 3500 BC. Until

2250-448: Is the process of extracting bioenergy from biomass and capturing and storing the carbon dioxide (CO 2 ) that is produced. Greenhouse gas emissions from bioenergy can be low because when vegetation is harvested for bioenergy, new vegetation can grow that will absorb CO 2 from the air through photosynthesis . After the biomass is harvested, energy ("bioenergy") is extracted in useful forms (electricity, heat, biofuels , etc.) as

2325-662: Is to slow and eventually stop climate change , which is widely agreed to be caused mostly by greenhouse gas emissions . In general, renewable energy sources cause much lower emissions than fossil fuels. The International Energy Agency estimates that to achieve net zero emissions by 2050, 90% of global electricity generation will need to be produced from renewable sources. Renewables also cause much less air pollution than fossil fuels, improving public health, and are less noisy . The deployment of renewable energy still faces obstacles, especially fossil fuel subsidies , lobbying by incumbent power providers, and local opposition to

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2400-463: The 2023 United Nations Climate Change Conference , around three-quarters of the world's countries set a goal of tripling renewable energy capacity by 2030. The European Union aims to generate 40% of its electricity from renewables by the same year. Renewable energy is more evenly distributed around the world than fossil fuels, which are concentrated in a limited number of countries. It also brings health benefits by reducing air pollution caused by

2475-474: The Fischer-Tropsch synthesis . Like coal, biomass can be converted into multiple commodity chemicals. Biochemical processes have developed in nature to break down the molecules of which biomass is composed, and many of these can be harnessed. In most cases, microorganisms are used to perform the conversion. The processes are called anaerobic digestion , fermentation , and composting . Based on

2550-494: The NASA Office of Science and Technology Policy examined the concept and concluded that with current and near-future technologies it would be economically uncompetitive. Collection of static electricity charges from water droplets on metal surfaces is an experimental technology that would be especially useful in low-income countries with relative air humidity over 60%. Breeder reactors could, in principle, depending on

2625-571: The decay , fission or fusion of elemental atoms Perpetual motion or "free energy", an elusive energy source which would violate the laws of thermodynamics Art, entertainment, and media [ edit ] New Energy , an album by British musician Four Tet Businesses and organizations [ edit ] Icelandic New Energy , Iceland energy company promoting hydrogen fuel Institute of Nuclear and New Energy Technology , China New Energy and Industrial Technology Development Organization (NEDO), Japan Topics referred to by

2700-574: The mantle and core . Geothermal energy extraction is viable mostly in countries located on tectonic plate edges, where the Earth's hot mantle is more exposed. As of 2023, the United States has by far the most geothermal capacity (2.7 GW, or less than 0.2% of the country's total energy capacity ), followed by Indonesia and the Philippines. Global capacity in 2022 was 15 GW. Geothermal energy can be either used directly to heat homes, as

2775-400: The 20th century, it was primarily used to power ships, windmills and water pumps. Today, the vast majority of wind power is used to generate electricity using wind turbines. Modern utility-scale wind turbines range from around 600 kW to 9 MW of rated power. The power available from the wind is a function of the cube of the wind speed, so as wind speed increases, power output increases up to

2850-643: The biomass is utilized through combustion, fermentation, pyrolysis or other conversion methods. Using bioenergy releases CO 2 . In BECCS, some of the CO 2 is captured before it enters the atmosphere, and stored underground using carbon capture and storage technology. Under some conditions, BECCS can remove carbon dioxide from the atmosphere. The climate impact of bioenergy varies considerably depending on where biomass feedstocks come from and how they are grown. For example, burning wood for energy releases carbon dioxide; those emissions can be significantly offset if

2925-446: The burning of fossil fuels. The potential worldwide savings in health care costs have been estimated at trillions of dollars annually. The two most important forms of renewable energy, solar and wind, are intermittent energy sources : they are not available constantly, resulting in lower capacity factors . In contrast, fossil fuel power plants are usually able to produce precisely the amount of energy an electricity grid requires at

3000-778: The cold outer space. Solar energy hits the surface and atmosphere of the earth and produces heat. Using various theorized devices like emissive energy harvester (EEH) or thermoradiative diode, this energy flow can be converted into electricity. In theory, this technology can be used during nighttime. Producing liquid fuels from oil-rich (fat-rich) varieties of algae is an ongoing research topic. Various microalgae grown in open or closed systems are being tried including some systems that can be set up in brownfield and desert lands. There have been numerous proposals for space-based solar power , in which very large satellites with photovoltaic panels would be equipped with microwave transmitters to beam power back to terrestrial receivers. A 2024 study by

3075-554: The crops used to produce bioethanol and biodiesel are grown specifically for this purpose, although used cooking oil accounted for 14% of the oil used to produce biodiesel as of 2015. The biomass used to produce biofuels varies by region. Maize is the major feedstock in the United States, while sugarcane dominates in Brazil. In the European Union, where biodiesel is more common than bioethanol, rapeseed oil and palm oil are

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3150-412: The deforestation of tropical rainforests in Brazil and Indonesia. In addition, burning biomass still produces carbon emissions, although much less than fossil fuels (39 grams of CO 2 per megajoule of energy, compared to 75 g/MJ for fossil fuels). Some biomass sources are unsustainable at current rates of exploitation (as of 2017). Biofuels are primarily used in transportation, providing 3.5% of

3225-425: The dominant mechanism to upgrade biomass into a better and more practical fuel. The basic alternatives are torrefaction , pyrolysis , and gasification , these are separated mainly by the extent to which the chemical reactions involved are allowed to proceed (mainly controlled by the availability of oxygen and conversion temperature). Many chemical conversions are based on established coal-based processes, such as

3300-585: The fastest-growing renewable energy technology. It is cheap, low-maintenance and scalable; adding to an existing PV installation as demanded arises is simple. Its main disadvantage is its poor performance in cloudy weather. PV systems range from small, residential and commercial rooftop or building integrated installations, to large utility-scale photovoltaic power station . A household's solar panels can either be used for just that household or, if connected to an electrical grid, can be aggregated with millions of others. The first utility-scale solar power plant

3375-531: The form of heat for biomass, and electricity for wind, hydro and solar). Lifecycle surface power density includes land used by all supporting infrastructure, manufacturing, mining/harvesting and decommissioning. Another estimate puts the values at 0.08 W/m for biomass, 0.14 W/m for hydro, 1.84 W/m for wind, and 6.63 W/m for solar ( median values, with none of the renewable sources exceeding 10 W/m ). Carbon capture and storage technology can be used to capture emissions from bioenergy power plants. This process

3450-548: The fuel cycle employed, extract almost all of the energy contained in uranium or thorium , decreasing fuel requirements by a factor of 100 compared to widely used once-through light water reactors , which extract less than 1% of the energy in the actinide metal (uranium or thorium) mined from the earth. The high fuel-efficiency of breeder reactors could greatly reduce concerns about fuel supply, energy used in mining, and storage of radioactive waste . With seawater uranium extraction (currently too expensive to be economical), there

3525-412: The fuels either grow on arable land but are byproducts of the main crop, or they are grown on marginal land. Waste from industry, agriculture, forestry and households can also be used for second-generation biofuels, using e.g. anaerobic digestion to produce biogas , gasification to produce syngas or by direct combustion. Cellulosic biomass , derived from non-food sources, such as trees and grasses,

3600-581: The future, more of the harvested pulpwood must go to pellet mills. However, the harvest of pulpwood (tree thinnings) removes the possibility for these trees to grow old and therefore maximize their carbon holding capacity. Compared to pulpwood, sawmill residues have lower net emissions: "Some types of biomass feedstock can be carbon-neutral, at least over a period of a few years, including in particular sawmill residues. These are wastes from other forest operations that imply no additional harvesting, and if otherwise burnt as waste or left to rot would release carbon to

3675-436: The global bioenergy is produced from forest resources. Generally, bioenergy expansion fell by 50% in 2020. China and Europe are the only two regions that reported significant expansion in 2020, adding 2 GW and 1.2 GW of bioenergy capacity, respectively. Almost all available sawmill residue is already being utilized for pellet production, so there is no room for expansion. For the bioenergy sector to significantly expand in

3750-691: The horizontal axis units currently in use. As offshore wind speeds average ~90% greater than that of land, offshore resources can contribute substantially more energy than land-stationed turbines. Investments in wind technologies reached USD 161 billion in 2020, with onshore wind dominating at 80% of total investments from 2013 to 2022. Offshore wind investments nearly doubled to USD 41 billion between 2019 and 2020, primarily due to policy incentives in China and expansion in Europe. Global wind capacity increased by 557 GW between 2013 and 2021, with capacity additions increasing by an average of 19% each year. Since water

3825-408: The main feedstocks. China, although it produces comparatively much less biofuel, uses mostly corn and wheat. In many countries, biofuels are either subsidized or mandated to be included in fuel mixtures . There are many other sources of bioenergy that are more niche, or not yet viable at large scales. For instance, bioethanol could be produced from the cellulosic parts of crops, rather than only

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3900-504: The main sequence of stellar evolution. Artificial photosynthesis uses techniques including nanotechnology to store solar electromagnetic energy in chemical bonds by splitting water to produce hydrogen and then using carbon dioxide to make methanol. Researchers in this field strived to design molecular mimics of photosynthesis that use a wider region of the solar spectrum, employ catalytic systems made from abundant, inexpensive materials that are robust, readily repaired, non-toxic, stable in

3975-433: The material that is fossilised or embedded in geological formations". This means that coal or other fossil fuels is not a form of biomass in this context. The term traditional biomass for bioenergy means "the combustion of wood, charcoal, agricultural residues and/or animal dung for cooking or heating in open fires or in inefficient stoves as is common in low-income countries ". Since biomass can also be used as

4050-456: The maximum output for the particular turbine. Areas where winds are stronger and more constant, such as offshore and high-altitude sites, are preferred locations for wind farms. Wind-generated electricity met nearly 4% of global electricity demand in 2015, with nearly 63 GW of new wind power capacity installed. Wind energy was the leading source of new capacity in Europe, the US and Canada, and

4125-472: The medium-term, this variability may require keeping some gas-fired power plants or other dispatchable generation on standby until there is enough energy storage, demand response , grid improvement, and/or baseload power from non-intermittent sources. In the long-term, energy storage is an important way of dealing with intermittency. Using diversified renewable energy sources and smart grids can also help flatten supply and demand. Sector coupling of

4200-788: The past decade, making them more competitive with traditional fossil fuels. In most countries, photovoltaic solar or onshore wind are the cheapest new-build electricity. From 2011 to 2021, renewable energy grew from 20% to 28% of global electricity supply. Power from the sun and wind accounted for most of this increase, growing from a combined 2% to 10%. Use of fossil energy shrank from 68% to 62%. In 2022, renewables accounted for 30% of global electricity generation and are projected to reach over 42% by 2028. Many countries already have renewables contributing more than 20% of their total energy supply, with some generating over half or even all their electricity from renewable sources. The main motivation to replace fossil fuels with renewable energy sources

4275-571: The power generation sector with other sectors may increase flexibility: for example the transport sector can be coupled by charging electric vehicles and sending electricity from vehicle to grid . Similarly the industry sector can be coupled by hydrogen produced by electrolysis, and the buildings sector by thermal energy storage for space heating and cooling. Building overcapacity for wind and solar generation can help ensure sufficient electricity production even during poor weather. In optimal weather, it may be necessary to curtail energy generation if it

4350-488: The primary challenges for new developments. It is popular to repower old dams thereby increasing their efficiency and capacity as well as quicker responsiveness on the grid. Where circumstances permit existing dams such as the Russell Dam built in 1985 may be updated with "pump back" facilities for pumped-storage which is useful for peak loads or to support intermittent wind and solar power. Because dispatchable power

4425-408: The renewable energy sector. Globally in 2020 there are over 10 million jobs associated with the renewable energy industries, with solar photovoltaics being the largest renewable employer. The clean energy sectors added about 4.7 million jobs globally between 2019 and 2022, totaling 35 million jobs by 2022. Bioenergy Bioenergy can help with climate change mitigation but in some cases

4500-441: The required biomass production can increase greenhouse gas emissions or lead to local biodiversity loss . The environmental impacts of biomass production can be problematic, depending on how the biomass is produced and harvested. The IEA 's Net Zero by 2050 scenario calls for traditional bioenergy to be phased out by 2030, with modern bioenergy's share increasing from 6.6% in 2020 to 13.1% in 2030 and 18.7% in 2050. Bioenergy has

4575-417: The same term [REDACTED] This disambiguation page lists articles associated with the title New energy . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=New_energy&oldid=1131630156 " Category : Disambiguation pages Hidden categories: Short description

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4650-585: The second largest in China. In Denmark, wind energy met more than 40% of its electricity demand while Ireland, Portugal and Spain each met nearly 20%. Globally, the long-term technical potential of wind energy is believed to be five times total current global energy production, or 40 times current electricity demand, assuming all practical barriers needed were overcome. This would require wind turbines to be installed over large areas, particularly in areas of higher wind resources, such as offshore, and likely also industrial use of new types of VAWT turbines in addition to

4725-527: The sector's increasing maturity and cost reductions, particularly in solar photovoltaic (PV), which accounted for 90% of total investments. China and the United States were the main recipients, collectively making up about half of all solar investments since 2013. Despite reductions in Japan and India due to policy changes and COVID-19 , growth in China, the United States, and a significant increase from Vietnam's feed-in tariff program offset these declines. Globally,

4800-418: The seed as is common today. Sweet sorghum may be a promising alternative source of bioethanol, due to its tolerance of a wide range of climates. Cow dung can be converted into methane. There is also a great deal of research involving algal fuel , which is attractive because algae is a non-food resource, grows around 20 times faster than most food crops, and can be grown almost anywhere. Geothermal energy

4875-451: The solar sector added 714 gigawatts (GW) of solar PV and concentrated solar power (CSP) capacity between 2013 and 2021, with a notable rise in large-scale solar heating installations in 2021, especially in China, Europe, Turkey, and Mexico. A photovoltaic system , consisting of solar cells assembled into panels , converts light into electrical direct current via the photoelectric effect . PV has several advantages that make it by far

4950-441: The source of biomass, biofuels are classified broadly into two major categories, depending if food crops are used or not: First-generation (or "conventional") biofuels are made from food sources grown on arable lands, such as sugarcane and maize . Sugars present in this biomass are fermented to produce bioethanol , an alcohol fuel which serves as an additive to gasoline, or in a fuel cell to produce electricity. Bioethanol

5025-468: The technology employing the most at almost 4 million. However, as of February 2024, the world's supply of workforce for solar energy is lagging greatly behind demand as universities worldwide still produce more workforce for fossil fuels than for renewable energy industries. In 2021, China accounted for almost half of the global increase in renewable electricity. There are 3,146 gigawatts installed in 135 countries, while 156 countries have laws regulating

5100-407: The ten biggest solar power stations are in China, including the biggest, Golmud Solar Park in China. Unlike photovoltaic cells that convert sunlight directly into electricity, solar thermal systems convert it into heat. They use mirrors or lenses to concentrate sunlight onto a receiver, which in turn heats a water reservoir. The heated water can then be used in homes. The advantage of solar thermal

5175-501: The term is not synonymous with low-carbon energy . Some non-renewable sources of energy, such as nuclear power , generate almost no emissions, while some renewable energy sources can be very carbon-intensive, such as the burning of biomass if it is not offset by planting new plants. Renewable energy is also distinct from sustainable energy , a more abstract concept that seeks to group energy sources based on their overall permanent impact on future generations of humans. For example, biomass

5250-422: The trees that were harvested are replaced by new trees in a well-managed forest, as the new trees will absorb carbon dioxide from the air as they grow. However, the establishment and cultivation of bioenergy crops can displace natural ecosystems , degrade soils , and consume water resources and synthetic fertilisers. Approximately one-third of all wood used for traditional heating and cooking in tropical areas

5325-484: The use of land for renewable installations. Like all mining, the extraction of minerals required for many renewable energy technologies also results in environmental damage . In addition, although most renewable energy sources are sustainable , some are not. Renewable energy is usually understood as energy harnessed from continuously occurring natural phenomena. The International Energy Agency defines it as "energy derived from natural processes that are replenished at

5400-484: The world's transport energy demand in 2022, up from 2.7% in 2010. Biojet is expected to be important for short-term reduction of carbon dioxide emissions from long-haul flights. Aside from wood, the major sources of bioenergy are bioethanol and biodiesel . Bioethanol is usually produced by fermenting the sugar components of crops like sugarcane and maize , while biodiesel is mostly made from oils extracted from plants, such as soybean oil and corn oil . Most of

5475-502: The world, depending on the cost of drilling. EGS projects have so far primarily been limited to demonstration plants , as the technology is capital-intensive due to the high cost of drilling. Marine energy (also sometimes referred to as ocean energy) is the energy carried by ocean waves , tides , salinity , and ocean temperature differences . Technologies to harness the energy of moving water include wave power , marine current power , and tidal power . Reverse electrodialysis (RED)

5550-455: Was 1,360 GW. Only a third of the world's estimated hydroelectric potential of 14,000 TWh/year has been developed. New hydropower projects face opposition from local communities due to their large impact, including relocation of communities and flooding of wildlife habitats and farming land. High cost and lead times from permission process, including environmental and risk assessments, with lack of environmental and social acceptance are therefore

5625-522: Was built in 1982 in Hesperia, California by ARCO . The plant was not profitable and was sold eight years later. However, over the following decades, PV cells became significantly more efficient and cheaper. As a result, PV adoption has grown exponentially since 2010. Global capacity increased from 230 GW at the end of 2015 to 890 GW in 2021. PV grew fastest in China between 2016 and 2021, adding 560 GW, more than all advanced economies combined. Four of

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