Distributed generation, also distributed energy, on-site generation (OSG), or district/decentralized energy, is electrical generation and storage performed by a variety of small, grid-connected or distribution system-connected devices referred to as distributed energy resources (DER).
The Electricity Supply Board is a state owned electricity company based in Ireland with operations worldwide. While historically a monopoly, the ESB now operates as a commercial semi-state concern in a "liberalised" and competitive market. It is a statutory corporation whose members are appointed by the government of Ireland.
The National Grid is the high-voltage electric power transmission network serving Great Britain, connecting power stations and major substations, and ensuring that electricity generated anywhere on the grid can be used to satisfy demand elsewhere. The network serves the majority of Great Britain and some of the surrounding islands. It does not cover Northern Ireland, which is part of the Irish single electricity market.
Northern Ireland Electricity Networks Limited (NIE Networks) is the electricity asset owner of the transmission and distribution infrastructure in Northern Ireland, established in 1993 when the business was privatised. NIE Networks does not generate or supply electricity. Since 2010 it has been a subsidiary of ESB Group.
The East–West Interconnector is a 500 MW high-voltage direct current submarine and subsoil power cable from 2012 which connects the Irish and British electricity markets, between Dublin and the Wales/England border. The project was developed by the Irish national grid operator EirGrid.
A virtual power plant (VPP) is a system that integrates multiple, possibly heterogeneous, power resources to provide grid power. A VPP typically sells its output to an electric utility. VPPs allow energy resources that are individually too small to be of interest to a utility to aggregate and market their power. As of 2024, VPPs operated in the United States, Europe, and Australia.
EirGrid plc is the state-owned electric power transmission operator in Ireland. It is a public limited company registered under the Companies Acts; its shares are held by the Minister for the Environment, Climate and Communications. It is one of a number of Irish state-sponsored bodies and is regulated by the Commission for Regulation of Utilities.
A grid-tied electrical system, also called tied to grid or grid tie system, is a semi-autonomous electrical generation or grid energy storage system which links to the mains to feed excess capacity back to the local mains electrical grid. When insufficient electricity is available, electricity drawn from the mains grid can make up the shortfall. Conversely when excess electricity is available, it is sent to the main grid. When the Utility or network operator restricts the amount of energy that goes into the grid, it is possible to prevent any input into the grid by installing Export Limiting devices.
An electrical grid is an interconnected network for electricity delivery from producers to consumers. Electrical grids consist of power stations, electrical substations to step voltage up or down, electric power transmission to carry power over long distances, and finally electric power distribution to customers. In that last step, voltage is stepped down again to the required service voltage. Power stations are typically built close to energy sources and far from densely populated areas. Electrical grids vary in size and can cover whole countries or continents. From small to large there are microgrids, wide area synchronous grids, and super grids. The combined transmission and distribution network is part of electricity delivery, known as the power grid.
The energy sector in Hawaii has rapidly adopted solar power due to the high costs of electricity, and good solar resources, and has one of the highest per capita rates of solar power in the United States. Hawaii's imported energy costs, mostly for imported petroleum and coal, are three to four times higher than the mainland, so Hawaii has motivation to become one of the highest users of solar energy. Hawaii was the first state in the United States to reach grid parity for photovoltaics. Its tropical location provides abundant ambient energy.
The National Grid covers most of mainland Great Britain and several of the surrounding islands, and there are interconnectors to Northern Ireland and to other European countries. Power is supplied to consumers at 230 volts AC with a frequency of 50 Hz. In 2023 about a third of electricity used in Britain was generated from fossil gas and two-thirds was low-carbon power. Wind generates the most low-carbon power, followed by nuclear some of which is imported from France. The government is aiming for greenhouse gas emissions from electricity in Britain to be net zero by 2035.
South Australia is a leader in utility-scale renewable energy generation, and also produces gas and uranium for electricity generation. Gas production is mostly concentrated in the Cooper Basin in the state's north-east. Gas is delivered from these fields by pipeline to users interstate and to Port Adelaide where it fuels three separate gas-fired power plants. Uranium is also mined in South Australia, though nuclear power generation is prohibited nationally. The Olympic Dam mine is the world's single largest known deposit of uranium and represents 30% of the world's total uranium resource. Many utility-scale wind farms and solar farms have been commissioned during the 21st century and geology with potential for geothermal energy has also been identified but is yet to be developed.
Ireland is a net energy importer. Ireland's import dependency decreased to 85% in 2014. 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.
Variable renewable energy (VRE) or intermittent renewable energy sources (IRES) are renewable energy sources that are not dispatchable due to their fluctuating nature, such as wind power and solar power, as opposed to controllable renewable energy sources, such as dammed hydroelectricity or bioenergy, or relatively constant sources, such as geothermal power.
Energy is a major area of the economy of California. California is the state with the largest population and the largest economy in the United States. It is second in energy consumption after Texas. As of 2018, per capita consumption was the fourth-lowest in the United States partially because of the mild climate and energy efficiency programs.
The electricity sector in Australia has been historically dominated by coal-fired power stations, but renewables are forming a rapidly growing fraction of supply. In 2021, Australia's electricity production reached 265 TWh, with coal accounting for 52.9% and natural gas for 18.8%. Renewable sources, comprising solar, wind, hydro, and bioenergy with waste, collectively made up 26.7% of the total electricity generation mix.
Under the original 2009 Renewable Energy Directive Ireland had set a target of producing 16% of all its energy needs from renewable energy sources by 2020 but that has been updated by a second Renewable Energy Directive whose targets are 32% by 2030. Between 2005 and 2014 the percentage of energy from renewable energy sources grew from just 3.1% to 8.6% of total final consumption. By 2020 the overall renewable energy share was 13.5%, short of its Renewable Energy Drive target of 16%. Renewable electricity accounted for 69% of all renewable energy used in 2020, up from two thirds (66.8%) in 2019.
The Commission for Regulation of Utilities, formerly known as the Commission for Energy Regulation, is Ireland's energy and water economic utility regulator.
The Tehachapi Energy Storage Project (TSP) is a 8MW/32MWh lithium-ion battery-based grid energy storage system at the Monolith Substation of Southern California Edison (SCE) in Tehachapi, California, sufficient to power between 1,600 and 2,400 homes for four hours. At the time of commissioning in 2014, it was the largest lithium-ion battery system operating in North America and one of the largest in the world. TSP is considered to be a modern-day energy storage pioneer with significant accomplishments that have proven the viability of utility-scale energy storage using lithium-ion technology. While originally envisioned as a research and development project, TSP operated as a distribution-level resource for SCE and for calendar year 2020, SCE reported that TSP operated in the wholesale energy market with revenue exceeding operating and maintenance costs. In 2021, SCE began the decommissioning of TSP, which was followed by formal decommissioning by state regulators in 2022. The physical dismantlement of TSP is expected to be completed by the end of 2022.
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