Primary energy (PE) is the energy found in nature that has not been subjected to any human engineered conversion process. It encompasses energy contained in raw fuels and other forms of energy, including waste, received as input to a system. Primary energy can be non-renewable or renewable.
Total primary energy supply (TPES) is the sum of production and imports, plus or minus stock changes, minus exports and international bunker storage. [3] The International Recommendations for Energy Statistics (IRES) prefers total energy supply (TES) to refer to this indicator. [4] These expressions are often used to describe the total energy supply of a national territory.
Secondary energy is a carrier of energy, such as electricity. These are produced by conversion from a primary energy source.
Primary energy is used as a measure in energy statistics in the compilation of energy balances, [5] as well as in the field of energetics. In energetics, a primary energy source (PES) refers to the energy forms required by the energy sector to generate the supply of energy carriers used by human society. [6] Primary energy only counts raw energy and not usable energy and fails to account well for energy losses, particularly the large losses in thermal sources. It therefore generally grossly undercounts non thermal renewable energy sources .
Primary energy sources should not be confused with the energy system components (or conversion processes) through which they are converted into energy carriers.
Primary energy sources | converted by | Energy system component | to | Energy carriers (main) | ||
Non-renewable [nb 1] | Fossil fuels | Oil (or crude oil) | Oil refinery | Fuel oil | ||
Coal or natural gas | Fossil fuel power station | Enthalpy, mechanical work or electricity | ||||
Mineral fuels | Natural uranium [nb 2] | Nuclear power plant (thermonuclear fission) | Electricity | |||
Natural thorium | Thorium breeder reactor | Enthalpy or electricity | ||||
Renewable | Solar energy | Photovoltaic power plant (see also Solar power ) | Electricity | |||
Solar power tower, solar furnace (see also Solar thermal energy ) | Enthalpy | |||||
Wind energy | Wind farm (see also Wind power ) | Mechanical work or electricity | ||||
Falling and flowing water, tidal energy [7] | Hydropower station, wave farm, tidal power station | Mechanical work or electricity | ||||
Biomass sources | Biomass power plant | Enthalpy or electricity | ||||
Geothermal energy | Geothermal power station | Enthalpy or electricity |
Primary energy sources are transformed in energy conversion processes to more convenient forms of energy that can directly be used by society, such as electrical energy, refined fuels, or synthetic fuels such as hydrogen fuel. In the field of energetics, these forms are called energy carriers and correspond to the concept of "secondary energy" in energy statistics.
Energy carriers are energy forms which have been transformed from primary energy sources. Electricity is one of the most common energy carriers, being transformed from various primary energy sources such as coal, oil, natural gas, and wind. Electricity is particularly useful since it has low entropy (is highly ordered) and so can be converted into other forms of energy very efficiently. District heating is another example of secondary energy. [8]
According to the laws of thermodynamics, primary energy sources cannot be produced. They must be available to society to enable the production of energy carriers. [6]
Conversion efficiency varies. For thermal energy, electricity and mechanical energy production is limited by Carnot's theorem, and generates a lot of waste heat. Other non-thermal conversions can be more efficient. For example, while wind turbines do not capture all of the wind's energy, they have a high conversion efficiency and generate very little waste heat since wind energy is low entropy. In principle solar photovoltaic conversions could be very efficient, but current conversion can only be done well for narrow ranges of wavelength, whereas solar thermal is also subject to Carnot efficiency limits. Hydroelectric power is also very ordered, and converted very efficiently. The amount of usable energy is the exergy of a system.
Site energy is the term used in North America for the amount of end-use energy of all forms consumed at a specified location. This can be a mix of primary energy (such as natural gas burned at the site) and secondary energy (such as electricity). Site energy is measured at the campus, building, or sub-building level and is the basis for energy charges on utility bills. [9]
Source energy, in contrast, is the term used in North America for the amount of primary energy consumed in order to provide a facility's site energy. It is always greater than the site energy, as it includes all site energy and adds to it the energy lost during transmission, delivery, and conversion. [10] While source or primary energy provides a more complete picture of energy consumption, it cannot be measured directly and must be calculated using conversion factors from site energy measurements. [9] For electricity, a typical value is three units of source energy for one unit of site energy. [11] However, this can vary considerably depending on factors such as the primary energy source or fuel type, the type of power plant, and the transmission infrastructure. One full set of conversion factors is available as technical reference from Energy STAR. [12]
Either site or source energy can be an appropriate metric when comparing or analyzing energy use of different facilities. The U.S Energy Information Administration, for example, uses primary (source) energy for its energy overviews [13] but site energy for its Commercial Building Energy Consumption Survey [14] and Residential Building Energy Consumption Survey. [15] The US Environmental Protection Agency's Energy STAR program recommends using source energy, [16] and the US Department of Energy uses site energy in its definition of a zero net energy building. [17]
Where primary energy is used to describe fossil fuels, the embodied energy of the fuel is available as thermal energy and around two thirds is typically lost in conversion to electrical or mechanical energy. There are very much less significant conversion losses when hydroelectricity, wind and solar power produce electricity, but today's UN conventions on energy statistics counts the electricity made from hydroelectricity, wind and solar as the primary energy itself for these sources. One consequence of employing primary energy as an energy metric is that the contribution of hydro, wind and solar energy is under reported compared to fossil energy sources, and there is hence an international debate on how to count energy from non thermal renewables, with many estimates having them undercounted by a factor of about three. [18] The false notion that all primary energy from thermal fossil fuel sources has to be replaced by an equivalent amount of non thermal renewables (which is not necessary as conversion losses do not need to be replaced) has been termed the "primary energy fallacy".
Renewable 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 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 a fluctuating nature, such as wind power and solar power. In contrast, controllable renewable energy sources include dammed hydroelectricity, bioenergy, or geothermal power.
A non-renewable resource is a natural resource that cannot be readily replaced by natural means at a pace quick enough to keep up with consumption. An example is carbon-based fossil fuels. The original organic matter, with the aid of heat and pressure, becomes a fuel such as oil or gas. Earth minerals and metal ores, fossil fuels and groundwater in certain aquifers are all considered non-renewable resources, though individual elements are always conserved.
Energy development is the field of activities focused on obtaining sources of energy from natural resources. These activities include the production of renewable, nuclear, and fossil fuel derived sources of energy, and for the recovery and reuse of energy that would otherwise be wasted. Energy conservation and efficiency measures reduce the demand for energy development, and can have benefits to society with improvements to environmental issues.
Electric power systems consist of generation plants of different energy sources, transmission networks, and distribution lines. Each of these components can have environmental impacts at multiple stages of their development and use including in their construction, during the generation of electricity, and in their decommissioning and disposal. These impacts can be split into operational impacts and construction impacts. All forms of electricity generation have some form of environmental impact, but coal-fired power is the dirtiest. This page is organized by energy source and includes impacts such as water usage, emissions, local pollution, and wildlife displacement.
Japan is a major consumer of energy, ranking fifth in the world by primary energy use. Fossil fuels accounted for 88% of Japan's primary energy in 2019. Japan imports most of its energy due to scarce domestic resources. As of 2022, the country imports 97% of its oil and is the larger LNG importer globally.
The net capacity factor is the unitless ratio of actual electrical energy output over a given period of time to the theoretical maximum electrical energy output over that period. The theoretical maximum energy output of a given installation is defined as that due to its continuous operation at full nameplate capacity over the relevant period. The capacity factor can be calculated for any electricity producing installation, such as a fuel consuming power plant or one using renewable energy, such as wind, the sun or hydro-electric installations. The average capacity factor can also be defined for any class of such installations, and can be used to compare different types of electricity production.
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.
World energy resources are the estimated maximum capacity for energy production given all available resources on Earth. They can be divided by type into fossil fuel, nuclear fuel and renewable resources.
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.
According to data from the US Energy Information Administration, renewable energy accounted for 8.4% of total primary energy production and 21% of total utility-scale electricity generation in the United States in 2022.
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 Ethiopia includes energy and electricity production, consumption, transport, exportation, and importation in the country of Ethiopia.
The United States has the second largest electricity sector in the world, with 4,178 Terawatt-hours of generation in 2023. In 2023 the industry earned $491b in revenue at an average price of $0.127/kWh.
Different methods of electricity generation can incur a variety of different costs, which can be divided into three general categories: 1) wholesale costs, or all costs paid by utilities associated with acquiring and distributing electricity to consumers, 2) retail costs paid by consumers, and 3) external costs, or externalities, imposed on society.
Most energy in Israel comes from fossil fuels. The country's total primary energy demand is significantly higher than its total primary energy production, relying heavily on imports to meet its energy needs. Total primary energy consumption was 304 TWh (1.037 quad) in 2016, or 26.2 million tonne of oil equivalent.
Denmark is a leading country in renewable energy production and usage. Renewable energy sources collectively produced 81% of Denmark's electricity generation in 2022, and are expected to provide 100% of national electric power production from 2030. Including energy use in the heating/cooling and transport sectors, Denmark is expected to reach 100% renewable energy in 2050, up from the 34% recorded in 2021.
California produces more renewable energy than any other state in the United States except Texas. In 2018, California ranked first in the nation as a producer of electricity from solar, geothermal, and biomass resources and fourth in the nation in conventional hydroelectric power generation. As of 2017, over half of the electricity (52.7%) produced was from renewable sources.
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.