Sustainable energy is a principle in which human use of energy "meets the needs of the present without compromising the ability of future generations to meet their own needs." Sustainable energy strategies generally have two pillars: cleaner methods of producing energy and energy conservation.
Sustainable energy technologies are deployed to generate electricity, to heat and cool buildings, and to power transportation systems and machines. When referring to methods of producing energy, the term "sustainable energy" is often used interchangeably with the term "renewable energy". In general, renewable energy sources such as solar energy, wind energy, geothermal energy, and tidal energy, are widely considered to be sustainable energy sources. However, particular renewable energy projects, such as the clearing of forests for production of biofuels, can lead to similar or even worse environmental damage when compared with using fossil fuel energy. There is considerable controversy over whether nuclear energy can be considered sustainable.
Costs of sustainable energy sources have decreased immensely throughout the years, and continue to fall. Increasingly, effective government policies support investor confidence and these markets are expanding. Considerable progress is being made in the energy transition from fossil fuels to ecologically sustainable systems, to the point where many studies support 100% renewable energy.
The organizing principle for sustainability is sustainable development, which includes the four interconnected domains: ecology, economics, politics and culture. Sustainability science is the study of sustainable development and environmental science.
The concept of sustainable development was described by the World Commission on Environment and Development in its 1987 book Our Common Future. Its definition of "sustainability", now used widely, was, "Sustainable development should meet the needs of the present without compromising the ability of future generations to meet their own needs."
In its book, the Commission described four key elements of sustainability with respect to energy: the ability to increase the supply of energy to meet growing human needs, energy efficiency and conservation, public health and safety, and "protection of the biosphere and prevention of more localized forms of pollution." Various definitions of sustainable energy have been offered since then which are also based on the three pillars of sustainable development, namely environment, economy, and society.
As no source of energy meets these criteria perfectly, sustainable energy sources are sustainable only in comparison to other sources. The nonexistence of perfect energy sources means that promoting efficient use of energy is essential to sustainable energy strategies.
Green energy is energy that can be extracted, generated, and/or consumed without any significant negative impact to the environment. The planet has a natural capability to recover which means pollution that does not go beyond that capability can still be termed green. It represents those renewable energy resources and technologies that provide the highest environmental benefit. The U.S. Environmental Protection Agency defines green power as electricity produced from solar, wind, geothermal, biogas, biomass and low-impact small hydroelectric sources.
When referring to sources of energy, the terms "sustainable energy" and "renewable energy" are often used interchangeably, however particular renewable energy projects sometimes raise significant sustainability concerns. Renewable energy technologies are essential contributors to sustainable energy as they generally contribute to world energy security, reducing dependence on fossil fuel resources, and providing opportunities for mitigating greenhouse gases. Various Cost–benefit analysis work by a disparate array of specialists and agencies have been conducted to determine the cheapest and quickest paths to decarbonizing the energy supply of the world, with the topic being one of considerable controversy, particularly on the role of nuclear energy.
Among sources of renewable energy, hydroelectric plants have the advantages of being long-lived—many existing plants have operated for more than 100 years. Also, hydroelectric plants are clean and have few emissions. Criticisms directed at large-scale hydroelectric plants include: dislocation of people living where the reservoirs are planned, and release of significant amounts of carbon dioxide during construction and flooding of the reservoir.
However, it has been found that high emissions are associated only with shallow reservoirs in warm (tropical) locales, and recent innovations in hydropower turbine technology are enabling efficient development of low-impact run-of-the-river hydroelectricity projects. Generally speaking, hydroelectric plants produce much lower life-cycle emissions than other types of generation. Hydroelectric power, which underwent extensive development during growth of electrification in the 19th and 20th centuries, is experiencing resurgence of development in the 21st century. The areas of greatest hydroelectric growth are the booming economies of Asia. China is the development leader; however, other Asian nations are installing hydropower at a rapid pace. This growth is driven by much increased energy costs—especially for imported energy—and widespread desires for more domestically produced, clean, renewable, and economical generation.
Geothermal energy can be harnessed to for electricity generation and for heating. Technologies in use include dry steam power stations, flash steam power stations and binary cycle power stations. As of 2010, geothermal electricity generation is used in 24 countries, while geothermal heating is in use in 70 countries. International markets grew at an average annual rate of 5 percent over the three years to 2015, and global geothermal power capacity is expected to reach 14.5–17.6 GW by 2020.
Geothermal power is considered to be a sustainable, renewable source of energy because the heat extraction is small compared with the Earth's heat content. The greenhouse gas emissions of geothermal electric stations are on average 45 grams of carbon dioxide per kilowatt-hour of electricity, or less than 5 percent of that of conventional coal-fired plants. As a source of renewable energy for both power and heating, geothermal has the potential to meet 3-5% of global demand by 2050. With economic incentives, it is estimated that by 2100 it will be possible to meet 10% of global demand.
Biomass is biological material derived from living, or recently living organisms. As an energy source, biomass can either be burned to produce heat and to generate electricity, or converted to various forms of biofuel. Liquid biofuels such as biodiesel and ethanol are especially valued as energy sources for motor vehicles.
Biomass is extremely versatile and one of the most-used sources of renewable energy. It is available in many countries, which makes it attractive for reducing dependence on imported fossil fuels. If the production of biomass is well-managed, carbon emissions can be significantly offset by the absorption of carbon dioxide by the plants during their lifespans. If the biomass source is agricultural or municipal waste, burning it or converting it into biogas also provides a way to dispose of this waste.
As of 2012, wood remains the largest biomass energy source today. If biomass is harvested from crops, such as tree plantations, the cultivation of these crops can displace natural ecosystems, degrade soils, and consume water resources and synthetic fertilizers. In some cases, these impacts can actually result in higher overall carbon emissions compared to using petroleum-based fuels.
Use of farmland for growing fuel can result in less land being available for growing food. Since photosynthesis is inherently inefficient, and crops also require significant amounts of energy to harvest, dry, and transport, the amount of energy produced per unit of land area is very small, in the range of 0.25 W/m2 to 1.2 W/m2. In the United States, corn-based ethanol has replaced less than 10% of motor gasoline use since 2011, but has consumed around 40% of the annual corn harvest in the country. In Malaysia and Indonesia, the clearing of forests to produce palm oil for biodiesel has led to serious social and environmental effects, as these forests are critical carbon sinks and habitats for endangered species.
In Europe in the 19th century, there were about 200,000 windmills, slightly more than the modern wind turbines of the 21st century. They were mainly used to grind grain and to pump water. The age of coal powered steam engines replaced this early use of wind power.
Wind power has high potential and have already realised relatively low production costs. At the end of 2008, worldwide wind farm capacity was 120,791 megawatts (MW), representing an increase of 28.8 percent during the year, and wind power produced some 1.3% of global electricity consumption. Wind power accounts for approximately 20% of electricity use in Denmark, 9% in Spain, and 7% in Germany. However, it may be difficult to site wind turbines in some areas for aesthetic or environmental reasons, and it may be difficult to integrate wind power into electricity grids in some cases.
Solar heating systems generally consist of solar thermal collectors, a fluid system to move the heat from the collector to its point of usage, and a reservoir or tank for heat storage and subsequent use. The systems may be used to heat domestic hot water, swimming pool water, or for space heating. The heat can also be used for industrial applications or as an energy input for other uses such as cooling equipment. In many climates, a solar heating system can provide a very high percentage (20 to 80%) of domestic hot water energy. Energy received from the sun by the earth is that of electromagnetic radiation. Light ranges of visible, infrared, ultraviolet, x-rays, and radio waves received by the earth through solar energy. The highest power of radiation comes from visible light. Solar power is complicated due to changes in seasons and from day to night. Cloud cover can also add to complications of solar energy, and not all radiation from the sun reaches earth because it is absorbed and dispersed due to clouds and gases within the earth's atmospheres.
Solar thermal power stations have been successfully operating in California commercially since the late 1980s, including the largest solar power plant of any kind, the 350 MW Solar Energy Generating Systems. Nevada Solar One is another 64MW plant which has recently opened. Other parabolic trough power plants being proposed are two 50 MW plants in Spain, and a 100 MW plant in Israel.
Solar electricity production uses photovoltaic (PV) cells to convert light into electrical current. Photovoltaic modules can be integrated into buildings or used in photovoltaic power stations connected to the electrical grid. They are especially useful for providing electricity to remote areas.
Large national and regional research projects on artificial photosynthesis are designing nanotechnology-based systems that use solar energy to split water into hydrogen fuel. and a proposal has been made for a Global Artificial Photosynthesis project In 2011, researchers at the Massachusetts Institute of Technology (MIT) developed what they are calling an "Artificial Leaf", which is capable of splitting water into hydrogen and oxygen directly from solar power when dropped into a glass of water. One side of the "Artificial Leaf" produces bubbles of hydrogen, while the other side produces bubbles of oxygen.
Most current solar power plants are made from an array of similar units where each unit is continuously adjusted, e.g., with some step motors, so that the light converter stays in focus of the sun light. The cost of focusing light on converters such as high-power solar panels, Stirling engine, etc. can be dramatically decreased with a simple and efficient rope mechanics. In this technique many units are connected with a network of ropes so that pulling two or three ropes is sufficient to keep all light converters simultaneously in focus as the direction of the sun changes.
Research is ongoing in space-based solar power, a concept in which solar panels are launched into outer space and the energy they capture is transmitted back to Earth as microwaves. A test facility for the technology is being built in China.
Portugal has the world's first commercial wave farm, the Aguçadora Wave Park, under construction in 2007. The farm will initially use three Pelamis P-750 machines generating 2.25 MW. and costs are put at 8.5 million euro. Subject to successful operation, a further 70 million euro is likely to be invested before 2009 on a further 28 machines to generate 525 MW. Funding for a wave farm in Scotland was announced in February, 2007 by the Scottish Executive, at a cost of over 4 million pounds, as part of a £13 million funding packages for ocean power in Scotland. The farm will be the world's largest with a capacity of 3 MW generated by four Pelamis machines. (see also Wave farm).
In 2007, the world's first turbine to create commercial amounts of energy using tidal power was installed in the narrows of Strangford Lough in Northern Ireland, UK. The 1.2 MW underwater tidal electricity generator takes advantage of the fast tidal flow in the lough which can be up to 4m/s. Although the generator is powerful enough to power up to a thousand homes, the turbine has a minimal environmental impact, as it is almost entirely submerged, and the rotors turn slowly enough that they pose no danger to wildlife.
Solar and wind are intermittent energy sources that supply electricity 10-40% of the time, depending on the weather and the time of day. Most electric grids were constructed for non-intermittent energy sources such as hydroelectricity or coal-fired power plants. In general, up to around 30% of the energy supplied to an electric grid can be easily converted to intermittent sources.
If intermittent sources make up a larger percentage of the energy supply for a given electric grid, there are several possible approaches to ensuring that electricity generation can meet ongoing demand:
As of 2019, the cost and logistics of energy storage for large population centres is a significant challenge, although the cost of battery systems has plunged dramatically. For instance, a 2019 study found that for solar and wind energy to meet energy demand for a week of extreme cold in the eastern and midwest United States, energy storage capacity would have to increase from the 11 GW currently in place to 277.9 GW.
Some costs could potentially be reduced by making use of energy storage equipment the consumer buys and not the state. An example is batteries in electric cars that would double as an energy buffer for the electricity grid. Energy storage apparatus' as car batteries are also built with materials that pose a threat to the environment (e.g. Lithium). The combined production of batteries for such a large part of the population would still have environmental concerns.
To provide household electricity in remote areas (that is areas which are not connected to the mains electricity grid), energy storage is required for use with renewable energy. Energy generation and consumption systems used in the latter case are usually stand-alone power systems.
Energy from renewable sources can also be stored as heat or cold, through thermal energy storage technologies. For instance, summer heat can be stored for winter heating, or winter cold can be stored for summer air conditioning.
There is considerable controversy over whether nuclear power can be considered sustainable. Some forms of nuclear power (ones which are able to "burn" nuclear waste through a process known as nuclear transmutation, such as an Integral Fast Reactor, could belong in the "Green Energy" category). Nuclear power plants can be more or less eliminated from their problem of nuclear waste through the use of nuclear reprocessing and newer plants as fast breeder and nuclear fusion plants.
Some people, including Greenpeace founder and first member Patrick Moore, George Monbiot, Bill Gates and James Lovelock have specifically classified nuclear power as green energy. Others, including Greenpeace's Phil Radford disagree, claiming that the problems associated with radioactive waste and the risk of nuclear accidents (such as the Chernobyl disaster) pose an unacceptable risk to the environment and to humanity. However, newer nuclear reactor designs are capable of utilizing what is now deemed "nuclear waste" until it is no longer (or dramatically less) dangerous, and have design features that greatly minimize the possibility of a nuclear accident. These designs have yet to be commercialized. (See: Molten salt reactor)
In theory, the greenhouse gas emissions of fossil fuel power plants can be significantly reduced through carbon capture and storage, although this process is expensive. Some believe that fossil fuel burning, with carbon capture and storage, may have a role in a sustainable energy system.
Moving towards energy sustainability will require changes not only in the way energy is supplied, but in the way it is used, and reducing the amount of energy required to deliver various goods or services is essential. Opportunities for improvement on the demand side of the energy equation are as rich and diverse as those on the supply side, and often offer significant economic benefits.
Efficiency slows down energy demand growth so that rising clean energy supplies can make deep cuts in fossil fuel use. A recent historical analysis has demonstrated that the rate of energy efficiency improvements has generally been outpaced by the rate of growth in energy demand, which is due to continuing economic and population growth. As a result, despite energy efficiency gains, total energy use and related carbon emissions have continued to increase. Thus, given the thermodynamic and practical limits of energy efficiency improvements, slowing the growth in energy demand is essential. However, unless clean energy supplies come online rapidly, slowing demand growth will only begin to reduce total emissions; reducing the carbon content of energy sources is also needed. Any serious vision of a sustainable energy economy thus requires commitments to both renewables and efficiency.
In developing countries, an estimated 3 billion people rely on traditional cookstoves and open fires to burn biomass or coal for heating and cooking. This practice causes harmful local air pollution and increases danger from fires, resulting in an estimated 4.3 million deaths annually. Additionally, serious local environmental damage, including desertification, can be caused by excessive harvesting of wood and other combustible material. Promoting usage of cleaner fuels and more efficient technologies for cooking is therefore one of the top priorities of the United Nations Sustainable Energy for All initiative. Thus far, efforts to design cookstoves that are inexpensive, powered by sustainable energy sources, and acceptable to users have been mostly disappointing.
Climate change concerns coupled with high oil prices and increasing government support are driving increasing rates of investment in the sustainable energy industries, according to a trend analysis from the United Nations Environment Programme. According to UNEP, global investment in sustainable energy in 2007 was higher than previous levels, with $148 billion of new money raised in 2007, an increase of 60% over 2006. Total financial transactions in sustainable energy, including acquisition activity, was $204 billion.
Investment flows in 2007 broadened and diversified, making the overall picture one of greater breadth and depth of sustainable energy use. The mainstream capital markets are "now fully receptive to sustainable energy companies, supported by a surge in funds destined for clean energy investment". The increased levels of investment and the fact that much of the capital is coming from more conventional financial actors suggest that sustainable energy options are now becoming mainstream.
In several countries with common carrier arrangements, electricity retailing arrangements make it possible for consumers to purchase "green" electricity from either their utility or a green power provider. Electricity is considered to be green if it is produced from a source that produces relatively little pollution, and the concept is often considered equivalent to renewable energy.
In many countries, green energy currently provides a very small amount of electricity, generally contributing less than 2 to 5% to the overall pool of electricity offered by most utility companies, electric companies, or state power pools. In some U.S. states, local governments have formed regional power purchasing pools using Community Choice Aggregation and Solar Bonds to achieve a 51% renewable mix or higher, such as in the City of San Francisco.
By participating in a green energy program a consumer may be having an effect on the energy sources used and ultimately might be helping to promote and expand the use of green energy. They are also making a statement to policy makers that they are willing to pay a price premium to support renewable energy. Green energy consumers either obligate the utility companies to increase the amount of green energy that they purchase from the pool (so decreasing the amount of non-green energy they purchase), or directly fund the green energy through a green power provider. If insufficient green energy sources are available, the utility must develop new ones or contract with a third party energy supplier to provide green energy, causing more to be built. However, there is no way the consumer can check whether or not the electricity bought is "green" or otherwise.
In some countries such as the Netherlands, electricity companies guarantee to buy an equal amount of 'green power' as is being used by their green power customers. The Dutch government exempts green power from pollution taxes, which means green power is hardly any more expensive than other power.
Directive 2004/8/EC of the European Parliament and of the Council of 11 February 2004 on the promotion of cogeneration based on a useful heat demand in the internal energy market includes the article 5 (Guarantee of origin of electricity from high-efficiency cogeneration).
European environmental NGOs have launched an ecolabel for green power. The ecolabel is called EKOenergy. It sets criteria for sustainability, additionality, consumer information and tracking. Only part of electricity produced by renewables fulfills the EKOenergy criteria.
A Green Energy Supply Certification Scheme was launched in the United Kingdom in February 2010. This implements guidelines from the Energy Regulator, Ofgem, and sets requirements on transparency, the matching of sales by renewable energy supplies, and additionality.
The United States Department of Energy (DOE), the Environmental Protection Agency (EPA), and the Center for Resource Solutions (CRS) recognizes the voluntary purchase of electricity from renewable energy sources (also called renewable electricity or green electricity) as green power.
The most popular way to purchase renewable energy as revealed by NREL data is through purchasing Renewable Energy Certificates (RECs). According to a Natural Marketing Institute (NMI) survey 55 percent of American consumers want companies to increase their use of renewable energy.
DOE selected six companies for its 2007 Green Power Supplier Awards, including Constellation NewEnergy; 3Degrees; Sterling Planet; SunEdison; Pacific Power and Rocky Mountain Power; and Silicon Valley Power. The combined green power provided by those six winners equals more than 5 billion kilowatt-hours per year, which is enough to power nearly 465,000 average U.S. households. In 2014, Arcadia Power made RECS available to homes and businesses in all 50 states, allowing consumers to use "100% green power" as defined by the EPA's Green Power Partnership.
The U.S. Environmental Protection Agency (USEPA) Green Power Partnership is a voluntary program that supports the organizational procurement of renewable electricity by offering expert advice, technical support, tools and resources. This can help organizations lower the transaction costs of buying renewable power, reduce carbon footprint, and communicate its leadership to key stakeholders.
Throughout the country, more than half of all U.S. electricity customers now have an option to purchase some type of green power product from a retail electricity provider. Roughly one-quarter of the nation's utilities offer green power programs to customers, and voluntary retail sales of renewable energy in the United States totaled more than 12 billion kilowatt-hours in 2006, a 40% increase over the previous year.
In the United States, one of the main problems with purchasing green energy through the electrical grid is the current centralized infrastructure that supplies the consumer’s electricity. This infrastructure has led to increasingly frequent brown outs and black outs, high CO2 emissions, higher energy costs, and power quality issues. An additional $450 billion will be invested to expand this fledgling system over the next 20 years to meet increasing demand. In addition, this centralized system is now being further overtaxed with the incorporation of renewable energies such as wind, solar, and geothermal energies. Renewable resources, due to the amount of space they require, are often located in remote areas where there is a lower energy demand. The current infrastructure would make transporting this energy to high demand areas, such as urban centers, highly inefficient and in some cases impossible. In addition, despite the amount of renewable energy produced or the economic viability of such technologies only about 20 percent will be able to be incorporated into the grid. To have a more sustainable energy profile, the United States must move towards implementing changes to the electrical grid that will accommodate a mixed-fuel economy.
Several initiatives are being proposed to mitigate distribution problems. First and foremost, the most effective way to reduce USA’s CO2 emissions and slow global warming is through conservation efforts. Opponents of the current US electrical grid have also advocated for decentralizing the grid. This system would increase efficiency by reducing the amount of energy lost in transmission. It would also be economically viable as it would reduce the amount of power lines that will need to be constructed in the future to keep up with demand. Merging heat and power in this system would create added benefits and help to increase its efficiency by up to 80-90%. This is a significant increase from the current fossil fuel plants which only have an efficiency of 34%.
Those not satisfied with the third-party grid approach to green energy via the power grid can install their own locally based renewable energy system. Renewable energy electrical systems from solar to wind to even local hydro-power in some cases, are some of the many types of renewable energy systems available locally. Additionally, for those interested in heating and cooling their dwelling via renewable energy, geothermal heat pump systems that tap the constant temperature of the earth, which is around 7 to 15 degrees Celsius a few feet underground and increases dramatically at greater depths, are an option over conventional natural gas and petroleum-fueled heat approaches. Also, in geographic locations where the Earth's Crust is especially thin, or near volcanoes (as is the case in Iceland) there exists the potential to generate even more electricity than would be possible at other sites, thanks to a more significant temperature gradient at these locales.
The advantage of this approach in the United States is that many states offer incentives to offset the cost of installation of a renewable energy system. In California, Massachusetts and several other U.S. states, a new approach to community energy supply called Community Choice Aggregation has provided communities with the means to solicit a competitive electricity supplier and use municipal revenue bonds to finance development of local green energy resources. Individuals are usually assured that the electricity they are using is actually produced from a green energy source that they control. Once the system is paid for, the owner of a renewable energy system will be producing their own renewable electricity for essentially no cost and can sell the excess to the local utility at a profit.
There are numerous organizations within the academic, federal, and commercial sectors conducting large scale advanced research in the field of sustainable energy. Scientific production towards sustainable energy systems is rising exponentially, growing from about 500 English journal papers only about renewable energy in 1992 to almost 9,000 papers in 2011.
Cellulosic ethanol has many benefits over traditional corn based-ethanol. It does not take away or directly conflict with the food supply because it is produced from wood, grasses, or non-edible parts of plants. Moreover, some studies have shown cellulosic ethanol to be potentially more cost effective and economically sustainable than corn-based ethanol. As of 2018, efforts to commercialize production of cellulosic ethanol have been mostly disappointing, but new commercial efforts are continuing. 
Algae fuel is an alternative to liquid fossil fuels that uses algae as its source of energy-rich oils. During the biofuel production process algae actually consumes the carbon dioxide in the air and turns it into oxygen through photosynthesis. In addition to its projected high yield, algaculture— unlike food crop-based biofuels — does not entail a decrease in food production, since it requires neither farmland nor fresh water. Between 2005 and 2012, dozens of companies attempted to commercialize production of algae fuel. By 2017, however, most efforts had been abandoned or changed to other applications, with only a few remaining.
There are potentially two sources of nuclear power. Fission is used in all current nuclear power plants. Fusion is the reaction that exists in stars, including the sun, and remains impractical for use on Earth, as fusion reactors are not yet available. However nuclear power is controversial politically and scientifically due to concerns about radioactive waste disposal, safety, the risks of a severe accident, and technical and economical problems in dismantling of old power plants.
Thorium is a fissionable material used in thorium-based nuclear power. The thorium fuel cycle claims several potential advantages over a uranium fuel cycle, including greater abundance, superior physical and nuclear properties, better resistance to nuclear weapons proliferation and reduced plutonium and actinide production. Therefore, it is sometimes referred as sustainable.
Currently, photovoltaic (PV) panels only have the ability to convert around 24% of the sunlight that hits them into electricity. At this rate, solar energy still holds many challenges for widespread implementation, but steady progress has been made in reducing manufacturing cost and increasing photovoltaic efficiency. In 2008, researchers at Massachusetts Institute of Technology (MIT) developed a method to store solar energy by using it to produce hydrogen fuel from water. Such research is targeted at addressing the obstacle that solar development faces of storing energy for use during nighttime hours when the sun is not shining. In February 2012, North Carolina-based Semprius Inc., announced that they had developed the world’s most efficient solar panel. The company claims that the prototype converts 33.9% of the sunlight that hits it to electricity, more than double the previous high-end conversion rate. Major projects on artificial photosynthesis or solar fuels are also under way in many developed nations.
Wind energy research dates back several decades to the 1970s when NASA developed an analytical model to predict wind turbine power generation during high winds. The Field Laboratory for Optimized Wind Energy (FLOWE) at Caltech was established to research renewable approaches to wind energy farming technology practices that have the potential to reduce the cost, size, and environmental impact of wind energy production. The president of Sky WindPower Corporation thinks that wind turbines will be able to produce electricity at a cent/kWh at an average which in comparison to coal-generated electricity is a fractional of the cost.
A wind farm is a group of wind turbines in the same location used to produce electric power. A large wind farm may consist of several hundred individual wind turbines, and cover an extended area of hundreds of square miles, but the land between the turbines may be used for agricultural or other purposes. A wind farm may also be located offshore.
Many of the largest operational onshore wind farms are located in the USA and China.  Europe leads in the use of wind power with almost 66 GW, about 66 percent of the total globally, with Denmark in the lead according to the countries installed per-capita capacity.
Wind power has expanded quickly, its share of worldwide electricity usage at the end of 2014 was 3.1%.
Geothermal energy is produced by tapping into the thermal energy created and stored within the earth. It arises from the radioactive decay of an isotope of potassium and other elements found in the Earth's crust. Geothermal energy can be obtained by drilling into the ground, very similar to oil exploration, and then it is carried by a heat-transfer fluid (e.g. water, brine or steam). Geothermal systems that are mainly dominated by water have the potential to provide greater benefits to the system and will generate more power. Within these liquid-dominated systems, there are possible concerns of subsidence and contamination of ground-water resources. Therefore, protection of ground-water resources is necessary in these systems. This means that careful reservoir production and engineering is necessary in liquid-dominated geothermal reservoir systems. Geothermal energy is considered sustainable because that thermal energy is constantly replenished.
Over $1 billion of federal money has been spent on the research and development of hydrogen and a medium for energy storage in the United States. (2012) Hydrogen is useful for energy storage, and for use in airplanes and ships, but is not practical for automobile use, as it is not very efficient, compared to using a battery — for the same cost a person can travel three times as far using a battery electric vehicle. Regardless of that opinion, Japanese car manufacturers Toyota and Honda currently offer hydrogen fuel-cell powered passenger vehicles for sale in Japan and the U.S.A. Experimental hydrogen fuel-cell city buses are currently operative in two U.S. transit districts, Alameda/Contra Costa county, California, and in Connecticut.. See List of fuel cell vehicles.
Around the world many sub-national governments - regions, states and provinces - have aggressively pursued sustainable energy investments. In the United States, California's leadership in renewable energy was recognised by The Climate Group when it awarded former Governor Arnold Schwarzenegger its inaugural award for international climate leadership in Copenhagen in 2009. In Australia, the state of South Australia - under the leadership of former Premier Mike Rann - has led the way with wind power comprising 26% of its electricity generation by the end of 2011, edging out coal fired generation for the first time. South Australia also has had the highest take-up per capita of household solar panels in Australia following the Rann Government's introduction of solar feed-in laws and educative campaign involving the installation of solar photovoltaic installations on the roofs of prominent public buildings, including the parliament, museum, airport and Adelaide Showgrounds pavilion and schools. Rann, Australia's first climate change minister, passed legislation in 2006 setting targets for renewable energy and emissions cuts, the first legislation in Australia to do so.
Also, in the European Union there is a clear trend of promoting policies encouraging investments and financing for sustainable energy in terms of energy efficiency, innovation in energy exploitation and development of renewable resources, with increased consideration of environmental aspects and sustainability.
In October 2018, the American Council for an Energy-Efficient Economy (ACEEE) released its annual "State Energy Efficiency Scorecard." The scorecard concluded that states and electric utility companies are continuing to expand energy efficiency measures in order to meet clean energy goals. In 2017, the U.S. spent $6.6 billion in electricity efficiency programs. $1.3 billion was spent on natural gas efficiency. These programs resulted in 27.3 million megawatt hours (MWh) of electricity saved.
Among scientific journals related to the interdisciplinary study of sustainable energy are:
Ashden is a London-based charity that works in the field of sustainable energy and development. Its mission is to "accelerate the transformation of our energy systems so that everyone, regardless of geography or status, has access to sustainable energy".
The organisation runs an annual awards scheme, the Ashden Awards, which works to uncover and promote “the most exciting sustainable energy pioneers” to help them scale their solutions and accelerate the transition to a Low-carbon economy. Ashden’s work also includes advocacy and research in the field of sustainable energy and a support program for the award winners.
Ashden was Founded in 2001 by Sarah Butler-Sloss from the Ashden Trust (one of the Sainsbury Family Charitable Trusts). In 2011 the charity changed its working name to Ashden, with its full name registered with the Charity Commission being 'Ashden, Sustainable solutions, better lives'. In 2019, Harriet Lamb became Ashden's CEO, having previously lead the international peace building charity International Alert.Climate Change and Sustainable Energy Act 2006
The Climate Change and Sustainable Energy Act 2006 (c 19) is an Act of the Parliament of the United Kingdom which aims to boost the number of heat and electricity microgeneration installations in the United Kingdom, so helping to cut carbon emissions and reduce fuel poverty.
The Act was piloted through the House of Commons as a Private Member's Bill by Mark Lazarowicz, MP.
The Rt Hon Eric Forth MP, a well known opponent of Private Members' Bills who often fillibustered them in Parliament, died during the passage of this bill through Parliament, after having prolonged the debate during Third Reading and Report for a number of days.Climate change in California
Climate change and the effects of global warming with regard to the climate in California primarily revolve around issues such as drought and the subsequent risk of wildfire and related occurrences. A 2011 study projected that the frequency and magnitude of both maximum and minimum temperatures would increase significantly as a result of global warming. The same study further projected that the frequency and magnitude of both maximum and minimum temperatures would likely increase as a result of global warming.David J. C. MacKay
Sir David John Cameron MacKay (22 April 1967 – 14 April 2016) was a British physicist, mathematician, and academic. He was the Regius Professor of Engineering in the Department of Engineering at the University of Cambridge and from 2009 to 2014 was Chief Scientific Adviser to the UK Department of Energy and Climate Change (DECC). MacKay authored the book Sustainable Energy – Without the Hot Air.Eastern Connecticut State University
Eastern Connecticut State University (Eastern, Eastern Connecticut, Eastern Connecticut State, or ECSU) is a public liberal arts university in Willimantic, Connecticut. Founded in 1889, it is the second-oldest campus in the Connecticut State University System and third-oldest public university in the state. Eastern is located on Windham Street in Willimantic, Connecticut, on 182 acres (0.74 km2) 30 minutes from Hartford, lying midway between New York City and Boston. Although the majority of courses are held on the main campus, select classes take place at Manchester Community College, Capital Community College, and a satellite center in Groton.
Eastern Connecticut State University is a member of the Connecticut State Colleges and Universities, with governance provided by the Connecticut Board of Regents for Higher Education.Efficient energy use
Efficient energy use, sometimes simply called energy efficiency, is the goal to reduce the amount of energy required to provide products and services. For example, insulating a home allows a building to use less heating and cooling energy to achieve and maintain a comfortable temperature. Installing LED lighting, fluorescent lighting, or natural skylight windows reduces the amount of energy required to attain the same level of illumination compared to using traditional incandescent light bulbs. Improvements in energy efficiency are generally achieved by adopting a more efficient technology or production process or by application of commonly accepted methods to reduce energy losses.
There are many motivations to improve energy efficiency. Reducing energy use reduces energy costs and may result in a financial cost saving to consumers if the energy savings offset any additional costs of implementing an energy-efficient technology. Reducing energy use is also seen as a solution to the problem of reducing greenhouse gas emissions. According to the International Energy Agency, improved energy efficiency in buildings, industrial processes and transportation could reduce the world's energy needs in 2050 by one third, and help control global emissions of greenhouse gases. Another important solution is to remove government-led energy subsidies that promote high energy consumption and inefficient energy use in more than half of the countries in the world.Energy efficiency and renewable energy are said to be the twin pillars of sustainable energy policy and are high priorities in the sustainable energy hierarchy. In many countries energy efficiency is also seen to have a national security benefit because it can be used to reduce the level of energy imports from foreign countries and may slow down the rate of energy at which domestic energy resources are depleted.Elphinstone Group
Elphinstone Group is an Australian company which manufactures and assembles heavy equipment for the mining industry. It has facilities Burnie, Tasmania and in Victoria. The corporate group includes the William Adams Caterpillar dealer in Tasmania and Victoria. Founder Dale Elphinstone started his working life as an apprentice at William Adams. He later bought the company. He is now counted as Tasmania's richest person.Elphinstone's brother Graeme owns a similarly-named company based on the east coast of Tasmania at Triabunna.Energy Retail Association
The Energy Retail Association (ERA) was a trade association which promoted the interests of electricity and gas retailers in the domestic market in Great Britain, formed in 2003. In April 2012 it merged with the Association of Electricity Producers and the UK Business Council for Sustainable Energy to become Energy UK.Energy in Ireland
Ireland is a net energy importer. Ireland's import dependency decreased to 85% in 2014 (from 89% in 2013).
The cost of all energy imports to Ireland was approximately €5.7 billion, down from €6.5 billion (revised) in 2013 due mainly to falling oil and, to a lesser extent, gas import prices.
Consumption of all fuels fell in 2014 with the exception of peat, renewables and non-renewable wastes.Final consumption of electricity in 2014 was 24 TWh. Renewable electricity generation, consisting of wind, hydro, landfill gas, biomass and biogas, accounted for 22.7% of gross electricity consumption.Energy-related CO2 emissions decreased by 1.2% in 2014 to a level 17% above 1990 levels.
When compared with 2005 energy-related CO2 emissions have fallen by 23%.
60.1% of Irish greenhouse gas emissions are caused by energy consumption.Florida Institute for Sustainable Energy
The Florida Institute for Sustainable Energy is a research institute at the University of Florida designed to develop energy efficient and environmentally sustainable technologies and practices, educate the public regarding energy and environmental technologies and trade-offs, and inform the larger policy debate on urgent, global issues of sustainable energy and environment. The objective is to improve the region and United States energy security by developing indigenous and environmentally sustainable energy resources while promoting energy policies that have a positive impact on Florida's unique environment.Greenhouse Solutions with Sustainable Energy
Greenhouse Solutions with Sustainable Energy is a 2007 book by Australian academic Mark Diesendorf. The book puts forward a set
of policies and strategies for implementing the most promising clean energy technologies by all spheres of government, business and community organisations. Greenhouse Solutions with Sustainable Energy suggests that a mix of efficient energy use, renewable energy sources and natural gas (as a transitional fuel) offers a clean and feasible energy future for Australia.Microgeneration
Microgeneration is the small-scale generation of heat and electric power by individuals, small businesses and communities to meet their own needs, as alternatives or supplements to traditional centralized grid-connected power. Although this may be motivated by practical considerations, such as unreliable grid power or long distance from the electrical grid, the term is mainly used currently for environmentally conscious approaches that aspire to zero or low-carbon footprints or cost reduction. It differs from micropower in that it is principally concerned with fixed power plants rather than for use with mobile devices.Renewable and Sustainable Energy Reviews
Renewable and Sustainable Energy Reviews is a peer-reviewed scientific journal covering research on sustainable energy. It is published in 12 issues per year by Elsevier and the editor-in-chief is L. Kazmerski (National Renewable Energy Laboratory). According to the Journal Citation Reports, the journal has a 2017 impact factor of 9.184.The journal considers articles based on the themes of energy resources, applications, utilization, environment, techno-socio-economic aspects, systems, and sustainability.In 2018, the journal accidentally retracted an article because of "human error". The article has since been reinstated.Renewable energy in Mexico
Renewable energy in Mexico contributes to 26 percent of electricity generation in Mexico. As of 2009, electricity generation from renewable energy comes from hydro power, geothermal, solar power and wind. There is a long term effort established to increase the use of renewable energy sources. The amount of geothermal energy used and harvested, places Mexico as number four in the world.
As the importance of clean sustainable energy becomes more prevalent, the country and government officials continue to invest in research and innovations to continue to allow Mexico to be a leading example of renewable energy. Predictions based on current energy standings lead the country to anticipate by the year 2035, the 26 percent renewable energy in Mexico will rise to 35 percent.
Not only will this prove a more sustainable future it also increases jobs in rural areas. Jobs increased by 14 percent within the last 8 years in the renewable energy sector. With the objection to create more in home jobs for residents of Mexico, an increase in sustainable energy, results in a lower demand for conventional fuels such as fuel oil, petrol gas, coal and natural gas. With a lower demand on these fuels, mainly gasoline and diesel and on the rise jet fuel, this will result in a lower need for imports. With relying on fewer imports, national security is higher.Risø DTU National Laboratory for Sustainable Energy
Risø DTU National Laboratory for Sustainable Energy (Danish: Risø DTU Nationallaboratoriet for Bæredygtig Energi) was a scientific research organization north of Roskilde, Denmark.
The Risø DTU organisation was founded in 1956 and dissolved on 1 January 2012. The location is now known as DTU Risø Campus and the buildings are home to a number of institutes under the Technical University of Denmark (DTU) and separately is also home to Aarhus University Dept of Environmental Science and part of Dept of Bioscience. Risø covers an area of more than 2.6 square kilometres.Sri Lanka Sustainable Energy Authority
The Sri Lanka Sustainable Energy Authority (or SLSEA) is the primary body responsible for the issuance of licenses for sustainable energy developments in Sri Lanka. In addition to being the key licence provider, it is also the organization responsible for promoting renewable energy and sustainable developments in the country.Sustainable Energy for All
Sustainable Energy for All (SEforALL) is an international organization launched by the then Secretary-General of the United Nations, Ban Ki-moon to help mobilize achievement of universal energy access, improve energy efficiency, and increase the use of renewable energy.
It was formally launched as an initiative in September 2011 and is headquartered in Vienna, Austria, with an executive office in Washington, DC.
Rachel Kyte took office as SEforALL’s CEO and Special Representative of the UN Secretary-General in January 2016.The Earth Institute
The Earth Institute was established at Columbia University in 1995. The research institute's stated mission is to address complex issues facing the planet and its inhabitants, with a focus on sustainable development. With an interdisciplinary approach this includes research in climate change, geology, global health, economics, management, agriculture, ecosystems, urbanization, energy, hazards, and water. The Earth Institute's activities are guided by the idea that science and technological tools that already exist could be applied to greatly improve conditions for the world's poor, while preserving the natural systems that support life on Earth.United Nations Environment Programme
The United Nations Environment Programme (UNEP), a programme of the United Nations, coordinates the organization's environmental activities and assists developing countries in implementing environmentally sound policies and practices. It was founded by Maurice Strong, its first director, as a result of the United Nations Conference on the Human Environment (Stockholm Conference) in June 1972 and has overall responsibility for environmental problems among United Nations agencies; however, international talks on specialized issues, such as addressing climate change or combating desertification, are overseen by other UN organizations, like the Bonn-based Secretariat of the United Nations Framework Convention on Climate Change and the United Nations Convention to Combat Desertification. UNEP's activities cover a wide range of issues regarding the atmosphere, marine and terrestrial ecosystems, environmental governance and green economy. It has played a significant role in developing international environmental conventions, promoting environmental science and information and illustrating the way those can be implemented in conjunction with policy, working on the development and implementation of policy with national governments, regional institutions in conjunction with environmental non-governmental organizations (NGOs). UNEP has also been active in funding and implementing environment related development projects.
UNEP frequently uses the alternative name UN Environment.UN Environment has aided in the formulation of guidelines and treaties on issues such as the international trade in potentially harmful chemicals, transboundary air pollution, and contamination of international waterways. Relevant documents, including scientific papers, are available via the UNEP Document Repository.The World Meteorological Organization and UN Environment established the Intergovernmental Panel on Climate Change (IPCC) in 1988. UN Environment is also one of several Implementing Agencies for the Global Environment Facility (GEF) and the Multilateral Fund for the Implementation of the Montreal Protocol, and it is also a member of the United Nations Development Group. The International Cyanide Management Code, a programme of best practice for the chemical's use at gold mining operations, was developed under UN Environment's aegis.
|Agreements and conferences|