Courtesy : en.wikipedia.org/
Sustainable energy
if it “meets the needs of the present without compromising the ability of future generations to meet their own needs”. Most definitions of sustainable energy include considerations of environmental aspects such as greenhouse gas emissions and social and economic aspects such as energy poverty. Renewable energy sources such as wind, hydroelectric power, solar, and geothermal energy are generally far more sustainable than fossil fuel sources. However, some renewable energy projects, such as the clearing of forests to produce biofuels, can cause severe environmental damage. The role of non-renewable energy sources in sustainable energy has been controversial. Nuclear power is a low-carbon source whose historic mortality rates are comparable to wind and solar, but its sustainability has been debated because of concerns about radioactive waste, nuclear proliferation, and accidents. Switching from coal to natural gas has environmental benefits, including a lower climate impact, but may lead to a delay in switching to more sustainable options. Carbon capture and storage can be built into power plants to remove their carbon dioxide (CO2) emissions, but is expensive and has seldom been implemented.
Fossil fuels provide 85% of the world’s energy consumption and the energy system is responsible for 76% of global greenhouse gas emissions. Around 790 million people in developing countries lack access to electricity and 2.6 billion rely on polluting fuels such as wood or charcoal to cook. Reducing greenhouse gas emissions to levels consistent with the 2015 Paris Agreement will require a system-wide transformation of the way energy is produced, distributed, stored, and consumed. The burning of fossil fuels and biomass is a major contributor to air pollution, which causes an estimated 7 million deaths each year. Therefore, the transition to a low-carbon energy system would have strong co-benefits for human health. Pathways exist to provide universal access to electricity and clean cooking in ways that are compatible with climate goals, while bringing major health and economic benefits to developing countries.
In proposed climate change mitigation pathways that are compatible with limiting global warming to 2 °C (3.6 °F), the world rapidly phases out coal-fired power plants, produces more electricity from clean sources such as wind and solar, and shifts towards using electricity instead of fuels in sectors such as transport and heating buildings. For some energy-intensive technologies and processes that are difficult to electrify, many pathways describe a growing role for hydrogen fuel produced from low-emission energy sources. To accommodate larger shares of variable renewable energy, electrical grids require flexibility through infrastructure such as energy storage. To make deep reductions in emissions, infrastructure and technologies that use energy, such as buildings and transport systems, would need to be changed to use clean forms of energy and also to conserve energy. Some critical technologies for eliminating energy-related greenhouse gas emissions are not yet mature.
Wind and solar energy generated 8.5% of worldwide electricity in 2019. This share has grown rapidly while costs have fallen and are projected to continue falling. The Intergovernmental Panel on Climate Change (IPCC) estimates that 2.5% of world gross domestic product (GDP) would need to be invested in the energy system each year between 2016 and 2035 to limit global warming to 1.5 °C (2.7 °F). Well-designed government policies that promote energy system transformation can lower greenhouse gas emissions and improve air quality. In many cases they also increase energy security. Policy approaches include carbon pricing, renewable portfolio standards, phase-outs of fossil fuel subsidies, and the development of infrastructure to support electrification and sustainable transport. Funding research, development, and demonstration of new clean energy technologies is also an important role of government.
Definitions and background
“Energy is the golden thread that connects economic growth, increased social equity, and an environment that allows the world to thrive. Development is not possible without energy, and sustainable development is not possible without sustainable energy.”
UN Secretary-General Ban Ki-moon
Definition
The United Nations Brundtland Commission described the concept of sustainable development, for which energy is a key component, in its 1987 report Our Common Future. It defined sustainable development as meeting “the needs of the present without compromising the ability of future generations to meet their own needs”.[1] This description of sustainable development has since been referenced in many definitions and explanations of sustainable energy.
No single interpretation of how the concept of sustainability applies to energy has gained worldwide acceptance. Working definitions of sustainable energy encompass multiple dimensions of sustainability such as environmental, economic, and social dimensions.Historically, the concept of sustainable energy development has focused on emissions and on energy security. Since the early 1990s, the concept has broadened to encompass wider social and economic issues.
The environmental dimension of sustainability includes greenhouse gas emissions, impacts on biodiversity and ecosystems, hazardous waste and toxic emissions, water consumption, and depletion of non-renewable resources.Energy sources with low environmental impact are sometimes called green energy or clean energy. The economic dimension of sustainability covers economic development, efficient use of energy, and energy security to ensure that each country has constant access to sufficient energy. Social issues include access to affordable and reliable energy for all people, workers’ rights, and land rights.
Environmental impacts
A woman in rural Rajasthan, India, collects firewood. The use of wood and other polluting fuels for cooking causes millions of deaths each year from indoor and outdoor air pollution.
The current energy system contributes to many environmental problems, including climate change, air pollution, biodiversity loss, the release of toxins into the environment, and water scarcity. As of 2019, 85% of the world’s energy needs are met by burning fossil fuels. Energy production and consumption are responsible for 76% of annual human-caused greenhouse gas emissions as of 2018. The 2015 international Paris Agreement on climate change aims to limit global warming to well below 2 °C (3.6 °F) and preferably to 1.5 °C (2.7 °F); achieving this goal will require that emissions be reduced as soon as possible and reach net-zero by mid-century.
The burning of fossil fuels and biomass is a major source of air pollution, which causes an estimated 7 million deaths each year. Fossil-fuel burning in power plants, vehicles, and factories is the main source of emissions that combine with oxygen in the atmosphere to cause acid rainAir pollution is the second-leading cause of death from non-infectious disease.An estimated 99% of the world’s population lives with levels of air pollution that exceed the World Health Organization recommended limits.
Cooking with polluting fuels such as wood, animal dung, coal, or kerosene is responsible for nearly all indoor air pollution, which causes an estimated 1.6 to 3.8 million deaths annually,and also contributes significantly to outdoor air pollution. Health effects are concentrated among women, who are likely to be responsible for cooking, and young children
Environmental impacts extend beyond the by-products of combustion. Oil spills at sea harm marine life and may cause fires which release toxic emissions. Around 10% of global water use goes to energy production, mainly for cooling in thermal energy plants. In dry regions, this contributes to water scarcity. Bioenergy production, coal mining and processing, and oil extraction also require large amounts of water. Excessive harvesting of wood and other combustible material for burning can cause serious local environmental damage, including desertification.
In 2021, UNECE published a lifecycle analysis of the environmental impact of numerous electricity generation technologies, accounting for the following: resource use (minerals, metals); land use; resource use (fossils); water use; particulate matter; photochemical ozone formation; ozone depletion; human toxicity (non-cancer); ionising radiation; human toxicity (cancer); eutrophication (terrestrial, marine, freshwater); ecotoxicity (freshwater); acidification; climate change.
