The United States is a highly developed free market economy. It is the world's largest economy by nominal GDP; it is also the second largest by purchasing power parity (PPP), behind China. It has the world's sixth highest per capita GDP (nominal) and the eighth highest per capita GDP (PPP) as of 2024. The U.S. accounted for 26% of the global economy in 2023 in nominal terms, and about 15.5% in PPP terms. The U.S. dollar is the currency of record most used in international transactions and is the world's reserve currency, backed by a large U.S. treasuries market, its role as the reference standard for the petrodollar system, and its linked eurodollar. Several countries use it as their official currency and in others it is the de facto currency. Since the end of World War II, the economy has achieved relatively steady growth, low unemployment and inflation, and rapid advances in technology.
The world economy or global economy is the economy of all humans in the world, referring to the global economic system, which includes all economic activities conducted both within and between nations, including production, consumption, economic management, work in general, financial transactions and trade of goods and services. In some contexts, the two terms are distinct: the "international" or "global economy" is measured separately and distinguished from national economies, while the "world economy" is simply an aggregate of the separate countries' measurements. Beyond the minimum standard concerning value in production, use and exchange, the definitions, representations, models and valuations of the world economy vary widely. It is inseparable from the geography and ecology of planet Earth.
Fuel efficiency is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical potential energy contained in a carrier (fuel) into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is often illustrated as a continuous energy profile. Non-transportation applications, such as industry, benefit from increased fuel efficiency, especially fossil fuel power plants or industries dealing with combustion, such as ammonia production during the Haber process.
Energy policies are the government's strategies and decisions regarding the production, distribution, and consumption of energy within a specific jurisdiction. Energy is essential for the functioning of modern economies because they require energy for many sectors, such as industry, transport, agriculture, housing. The main components of energy policy include legislation, international treaties, energy subsidies and other public policy techniques.
An emission intensity is the emission rate of a given pollutant relative to the intensity of a specific activity, or an industrial production process; for example grams of carbon dioxide released per megajoule of energy produced, or the ratio of greenhouse gas emissions produced to gross domestic product (GDP). Emission intensities are used to derive estimates of air pollutant or greenhouse gas emissions based on the amount of fuel combusted, the number of animals in animal husbandry, on industrial production levels, distances traveled or similar activity data. Emission intensities may also be used to compare the environmental impact of different fuels or activities. In some case the related terms emission factor and carbon intensity are used interchangeably. The jargon used can be different, for different fields/industrial sectors; normally the term "carbon" excludes other pollutants, such as particulate emissions. One commonly used figure is carbon intensity per kilowatt-hour (CIPK), which is used to compare emissions from different sources of electrical power.
The energy industry is the totality of all of the industries involved in the production and sale of energy, including fuel extraction, manufacturing, refining and distribution. Modern society consumes large amounts of fuel, and the energy industry is a crucial part of the infrastructure and maintenance of society in almost all countries.
Electric energy consumption is energy consumption in the form of electrical energy. About a fifth of global energy is consumed as electricity: for residential, industrial, commercial, transportation and other purposes. Quickly increasing this share by further electrification is extremely important to limit climate change, because most other energy is consumed by burning fossil fuels thus emitting greenhouse gases which trap heat.
Energy in the United States is obtained from a diverse portfolio of sources, although the majority came from fossil fuels in 2021, as 36% of the nation's energy originated from petroleum, 32% from natural gas, and 11% from coal. Electricity from nuclear power supplied 8% and renewable energy supplied 12%, which includes biomass, wind, hydro, solar and geothermal.
The energy policy of India is to increase the locally produced energy in India and reduce energy poverty, with more focus on developing alternative sources of energy, particularly nuclear, solar and wind energy. Net energy import dependency was 40.9% in 2021-22. The primary energy consumption in India grew by 13.3% in FY2022-23 and is the third biggest with 6% global share after China and USA. The total primary energy consumption from coal, crude oil, natural gas, nuclear energy, hydroelectricity and renewable power is 809.2 Mtoe in the calendar year 2018. In 2018, India's net imports are nearly 205.3 million tons of crude oil and its products, 26.3 Mtoe of LNG and 141.7 Mtoe coal totaling to 373.3 Mtoe of primary energy which is equal to 46.13% of total primary energy consumption. India is largely dependent on fossil fuel imports to meet its energy demands – by 2030, India's dependence on energy imports is expected to exceed 53% of the country's total energy consumption.
The energy efficiency in transport is the useful travelled distance, of passengers, goods or any type of load; divided by the total energy put into the transport propulsion means. The energy input might be rendered in several different types depending on the type of propulsion, and normally such energy is presented in liquid fuels, electrical energy or food energy. The energy efficiency is also occasionally known as energy intensity. The inverse of the energy efficiency in transport is the energy consumption in transport.
In energy conservation and energy economics, the rebound effect is the reduction in expected gains from new technologies that increase the efficiency of resource use, because of behavioral or other systemic responses. These responses diminish the beneficial effects of the new technology or other measures taken. A definition of the rebound effect is provided by Thiesen et al. (2008) as, “the rebound effect deals with the fact that improvements in efficiency often lead to cost reductions that provide the possibility to buy more of the improved product or other products or services.” A classic example from this perspective is a driver who substitutes a vehicle with a fuel-efficient version, only to reap the benefits of its lower operating expenses to commute longer and more frequently."
Iran possesses significant energy reserves, holding the position of the world's third-largest in proved oil reserves and the second-largest in natural gas reserves as of 2021. At the conclusion of the same year, Iran's share comprised 24% of the oil reserves in the Middle East and 12% of the worldwide total.
Efficient energy use, or energy efficiency, is the process of reducing the amount of energy required to provide products and services. There are many technologies and methods available that are more energy efficient than conventional systems. For example, insulating a building allows it to use less heating and cooling energy while still maintaining a comfortable temperature. Another method is to remove energy subsidies that promote high energy consumption and inefficient energy use. Improved energy efficiency in buildings, industrial processes and transportation could reduce the world's energy needs in 2050 by one third.
Despite abundant natural resources and a relatively small population, New Zealand is a net importer of energy, in the form of petroleum products. The ratio of non-renewable and renewable energy sources was fairly consistent from 1975 to 2008, with about 70 per cent of primary energy supply coming from hydrocarbon fuels. This ratio decreased to about 60 per cent in 2018. The proportion of non-renewable energy varies annually, depending on water flows into hydro-electricity lakes and demand for energy. In 2018, approximately 60% of primary energy was from non-renewable hydrocarbon fuels and 40% was from renewable sources. In 2007 energy consumption per capita was 120 gigajoules. Per capita energy consumption had increased 8 per cent since 1998. New Zealand uses more energy per capita than 17 of 30 OECD countries. New Zealand is one of 13 OECD countries that does not operate nuclear power stations.
EnergyinSaudi Arabia involves petroleum and natural gas production, consumption, and exports, and electricity production. Saudi Arabia is the world's leading oil producer and exporter. Saudi Arabia's economy is petroleum-based; oil accounts for 90% of the country's exports and nearly 75% of government revenue. The oil industry produces about 45% of Saudi Arabia's gross domestic product, against 40% from the private sector. Saudi Arabia has per capita GDP of $20,700. The economy is still very dependent on oil despite diversification, in particular in the petrochemical sector.
The energy mix is a group of different primary energy sources from which secondary energy for direct use - such as electricity - is produced. Energy mix refers to all direct uses of energy, such as transportation and housing, and should not be confused with power generation mix, which refers only to generation of electricity, as electricity only accounts for 20 % of the world's final energy consumption.
Energy in Qatar describes energy production, consumption, and policies of the State of Qatar. The International Monetary Fund ranked Qatar as having the fifth highest GDP per capita in 2016 with a 60,787 USD per capita nominal GDP over a population of 2.421 million inhabitants. In 2014, oil and natural gas production made up 51.1% of Qatar's nominal GDP. Thus, Qatar has a worldwide high ranking of per capita GDP due to its significance production and exports in both crude oil and natural gas in proportion to its relatively small population.
Energy in the Middle East describes energy and electricity production, consumption and import in the Middle East. Energy policy of the Middle East will describe the politics of the Middle East related to energy more in detail.
In economic and environmental fields, decoupling refers to an economy that would be able to grow without corresponding increases in environmental pressure. In many economies, increasing production (GDP) raises pressure on the environment. An economy that would be able to sustain economic growth while reducing the amount of resources such as water or fossil fuels used and delink environmental deterioration at the same time would be said to be decoupled. Environmental pressure is often measured using emissions of pollutants, and decoupling is often measured by the emission intensity of economic output.
World energy supply and consumption refers to the global supply of energy resources and its consumption. The system of global energy supply consists of the energy development, refinement, and trade of energy. Energy supplies may exist in various forms such as raw resources or more processed and refined forms of energy. The raw energy resources include for example coal, unprocessed oil & gas, uranium. In comparison, the refined forms of energy include for example refined oil that becomes fuel and electricity. Energy resources may be used in various different ways, depending on the specific resource, and intended end use. Energy production and consumption play a significant role in the global economy. It is needed in industry and global transportation. The total energy supply chain, from production to final consumption, involves many activities that cause a loss of useful energy.
