Combinations between different technologies to generate electric power
This article is about generating electricity from more than one source at the same location. For vehicles propelled by more than one type of power, see Hybrid vehicle. For electric vehicles propelled by more than one type of power, see Hybrid electric vehicle.
Hybrid power plants often contain a renewable energy component (such as PV) that is balanced via a second form of generation or storage such as a diesel genset, fuel cell or battery storage system[3]. They can also provide other forms of power such as heat for some applications.[4][5]
Hybrid power system
Hybrid systems, as the name implies, combine two or more modes of electricity generation together, usually using renewable technologies such as solar photovoltaic (PV) and wind turbines. Hybrid systems provide a high level of energy security through the mix of generation methods, and often will incorporate a storage system (battery, fuel cell) or small fossil fueled generator to ensure maximum supply reliability and security.[6]
Hybrid renewable energy systems are becoming popular as stand-alone power systems for providing electricity in remote areas due to advances in renewable energy technologies and subsequent rise in prices of petroleum products. A hybrid energy system, or hybrid power, usually consists of two or more renewable energy sources used together to provide increased system efficiency as well as greater balance in energy supply.[5]
Types
Hydro and solar
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Floating solar is usually added to existing hydro rather than building both together.
Solar and wind
Hybrid solar and wind systemBlock diagram of a PV/wind hybrid energy system
Another example of a hybrid energy system is a photovoltaic array coupled with a wind turbine.[7] This would create more output from the wind turbine during the winter, whereas during the summer, the solar panels would produce their peak output. Hybrid energy systems often yield greater economic and environmental returns than wind, solar, geothermal or trigeneration stand-alone systems by themselves.[8]
Horizontal axis wind-turbine, combined with a solar panel on a lighting pylon at Weihai, Shandong province, China
Combined use of wind+solar systems results, in many places, in a smoother/cleaner power output since the resources are anti-correlated. Therefore, the combined use of wind and solar systems is crucial for a large-scale grid integration.[9]
In 2019 in western Minnesota, a $5m hybrid system was installed. It runs 500kW of solar power through the inverter of a 2 MW wind turbine, increasing the capacity factor and reducing costs by $150,000 per year. Purchase contracts limits the local distributor to a 5% maximum of self-generation.[10][11]
The Pearl River Tower in Guangzhou, China, will mix solar panel on its windows and several wind turbines at different stories of its structure, allowing this tower to be energy positive.[citation needed]
In several parts of China & India, there are lighting pylons with combinations of solar panels and wind-turbines at their top. This allows space already used for lighting to be used more efficiently with two complementary energy productions units. Most common models use horizontal axis wind-turbines, but now models are appearing with vertical axis wind-turbines, using a helicoidal shaped, twisted-Savonius system.[citation needed]
Solar panels on the already existing wind turbines has been tested, but produced blinding rays of light that posed a threat to airplanes. A solution was to produce tinted solar panels that do not reflect as much light. Another proposed design was to have a vertical axis wind turbine coated in solar cells that are able to absorb sunlight from any angle.[12]
Other solar hybrids include solar-wind systems. The combination of wind and solar has the advantage that the two sources complement each other because the peak operating times for each system occur at different times of the day and year. The power generation of such a hybrid system is more constant and fluctuates less than each of the two component subsystems.[13]
Hydro and wind
A wind-hydro system generates electric energy combining wind turbines and pumped storage. The combination has been the subject of long-term discussion, and an experimental plant, which also tested wind turbines, was implemented by Nova Scotia Power at its Wreck Cove hydro electric power site in the late 1970s, but was decommissioned within ten years. Since, no other system has been implemented at a single location as of late 2010.[14]
Wind-hydro stations dedicate all, or a significant portion, of their wind power resources to pumping water into pumped storage reservoirs. These reservoirs are an implementation of grid energy storage.
Wind and its generation potential is inherently variable. However, when this energy source is used to pump water into reservoirs at an elevation (the principle behind pumped storage), the potential energy of the water is relatively stable and can be used to generate electrical power by releasing it into a hydropower plant when needed.[15] The combination has been described as particularly suited to islands that are not connected to larger grids.[14]
An installation at Ikaria Island, Greece, had entered the construction phase as of 2010.[14]
The island of El Hierro is where the first world's first wind-hydro power station is expected to be complete.[20]Current TV called this "a blueprint for a sustainable future on planet Earth". It was designed to cover between 80-100% of the island's power and was set to be operational in 2012.[21] However, these expectations were not realized in practice, probably due to inadequate reservoir volume and persistent problems with grid stability.[22]
Though Solar PV generates cheaper intermittent power during the day light time, it needs the support of sustainable power generation sources to provide round the clock power. Solar thermal plants with thermal storage are clean sustainable power generation to supply electricity round the clock.[24][25] They can cater the load demand perfectly and work as base load power plants when the extracted solar energy is found excess in a day.[26] Proper mix of solar thermal (thermal storage type) and solar PV can fully match the load fluctuations without the need of costly battery storage.[27][28]
During the day time, the additional auxiliary power consumption of a solar thermal storage power plant is nearly 10% of its rated capacity for the process of extracting solar energy in the form of thermal energy.[26] This auxiliary power requirement can be made available from cheaper solar PV plant by envisaging hybrid solar plant with a mix of solar thermal and solar PV plants at a site. Also to optimise the cost of power, generation can be from the cheaper solar PV plant (33% generation) during the day light whereas the rest of the time in a day is from the solar thermal storage plant (67% generation from Solar power tower and parabolic trough types) for meeting 24 hours base load operation.[29] When solar thermal storage plant is forced to idle due to lack of sunlight locally during cloudy days in monsoon season, it is also possible to consume (similar to a lesser efficient, huge capacity and low cost battery storage system) the cheap surplus / infirm power from solar PV, wind and hydro power plants by heating the hot molten salt to higher temperature for converting stored thermal energy in to electricity during the peak demand hours when the electricity sale price is profitable.[30][31]
Solar PV, battery and grid
System diagram of intelligent hybrid inverters used in domestic setting.
Solar PV gives variable output which can be buffered with battery storage. However, large variations exist in production over the day, as well in many places seasonally. The battery helps match the power with the load. A hybrid solar inverter additionally allows the storage of low cost electricity drawn down on cheap tariffs.[32]
In 2024, USA has 288 solar+battery power plants with a storage capacity at 7.8 GW power and 24.2 GWh energy.[33]
Successfully storing hydrogen has many issues which need to be overcome, such as embrittlement of the materials used in the power system.
This technology is being developed in many countries. In 2007 there was an IPO of an Australian firm called Wind Hydrogen that aimed to commercialise this technology in both Australia and the UK.[34] In 2008 the company changed its name and turned its operations to fossil fuel exploration.[35]
A wind-diesel hybrid power system combines diesel generators and wind turbines,[45] usually alongside ancillary equipment such as energy storage, power converters, and various control components, to generate electricity. They are designed to increase capacity and reduce the cost and environmental impact of electrical generation in remote communities and facilities that are not linked to a power grid.[45] Wind-diesel hybrid systems reduce reliance on diesel fuel, which creates pollution and is costly to transport.[45]
Wind-diesel generating systems have been under development and trialled in a number of locations during the latter part of the 20th century. A growing number of viable sites have been developed with increased reliability and minimized technical support costs in remote communities.[citation needed]
The successful integration of wind energy with diesel generating sets relies on complex controls to ensure correct sharing of intermittent wind energy and controllable diesel generation to meet the demand of the usually variable load. The common measure of performance for wind diesel systems is Wind Penetration which is the ratio between Wind Power and Total Power delivered, e.g. 60% wind penetration implies that 60% of the system power comes from the wind. Wind Penetration figures can be either peak or long term. Sites such as Mawson Station, Antarctica, as well as Coral Bay and Bremer Bay in Australia have peak wind penetrations of around 90%. Technical solutions to the varying wind output include controlling wind output using variable speed wind turbines (e.g. Enercon, Denham, Western Australia), controlling demand such as the heating load (e.g. Mawson), storing energy in a flywheel (e.g. Powercorp, Coral Bay). Some installations are now being converted to wind hydrogen systems such as on Ramea in Canada which is due for completion in 2010.[citation needed]
Recently,[when?] in Northern Canada wind-diesel hybrid power systems were built by the mining industry. In remote locations at Lac de Gras, in Canada's Northwest Territories, and Katinniq, Ungava Peninsula, Nunavik, two systems are used to save fuel at mines. There is another system in Argentina.[46]
Combined cycle hydrogen power plant
Renewable and conventional energy production in Germany over two weeks in 2022. In hours with low wind and PV production, hard coal and gas fill the gap. Nuclear and biomass show almost no flexibility. PV follows the increased consumption during daytime hours but varies seasonally.
At power stations that use compressed air energy storage (CAES), electrical energy is used to compress air and store it in underground facilities such as caverns or abandoned mines. During later periods of high electrical demand, the air is released to power turbines, generally using supplemental natural gas.[48] Power stations that make significant use of CAES are operational in McIntosh, Alabama, Germany, and Japan.[49] System disadvantages include some energy losses in the CAES process; also, the need for supplemental use of fossil fuels such as natural gas means that these systems do not completely make use of renewable energy.[50]
The Iowa Stored Energy Park, projected to begin commercial operation in 2015, will use wind farms in Iowa as an energy source in conjunction with CAES.[51]
Combining solar and geothermal is also possible.[52]
Solar and diesel
A common type is a photovoltaic diesel hybrid system,[53][54] combining photovoltaics (PV) and diesel generators, or diesel gensets, as PV has hardly any marginal cost and is treated with priority on the grid. The diesel gensets are used to constantly fill in the gap between the present load and the actual generated power by the PV system.[55]
As solar energy is fluctuating, and the generation capacity of the diesel genesets is limited to a certain range, it is often a viable option to include battery storage in order to optimize solar's contribution to the overall generation of the hybrid system.[55][56]
The best business cases for diesel reduction with solar and wind energy can normally be found in remote locations because these sites are often not connected to the grid and transport of diesel over long distances is expensive.[57] Many of these applications can be found in the mining sector [58] and on islands [55][59][60]
In 2015, a case-study conducted in seven countries concluded that in all cases generating costs can be reduced by hybridising mini-grids and isolated grids. However, financing costs for diesel-powered electricity grids with solar photovoltaics are crucial and largely depend on the ownership structure of the power plant. While cost reductions for state-owned utilities can be significant, the study also identified short-term economic benefits to be insignificant or even negative for non-public utilities, such as independent power producers, given historical costs at the time of the study.[61][62]
More than 2 sources
Adding wave power to wind and solar may be possible.[63]
Energy storage is the capture of energy produced at one time for use at a later time to reduce imbalances between energy demand and energy production. A device that stores energy is generally called an accumulator or battery. Energy comes in multiple forms including radiation, chemical, gravitational potential, electrical potential, electricity, elevated temperature, latent heat and kinetic. Energy storage involves converting energy from forms that are difficult to store to more conveniently or economically storable forms.
A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid.
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).
Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing. A PHS system stores energy in the form of gravitational potential energy of water, pumped from a lower elevation reservoir to a higher elevation. Low-cost surplus off-peak electric power is typically used to run the pumps. During periods of high electrical demand, the stored water is released through turbines to produce electric power.
Grid energy storage is a collection of methods used for energy storage on a large scale within an electrical power grid. Electrical energy is stored during times when electricity is plentiful and inexpensive or when demand is low, and later returned to the grid when demand is high, and electricity prices tend to be higher.
Peaking power plants, also known as peaker plants, and occasionally just "peakers", are power plants that generally run only when there is a high demand, known as peak demand, for electricity. Because they supply power only occasionally, the power supplied commands a much higher price per kilowatt hour than base load power. Peak load power plants are dispatched in combination with base load power plants, which supply a dependable and consistent amount of electricity, to meet the minimum demand.
Off-the-grid or off-grid is a characteristic of buildings and a lifestyle designed in an independent manner without reliance on one or more public utilities. The term "off-the-grid" traditionally refers to not being connected to the electrical grid, but can also include other utilities like water, gas, and sewer systems, and can scale from residential homes to small communities. Off-the-grid living allows for buildings and people to be self-sufficient, which is advantageous in isolated locations where normal utilities cannot reach and is attractive to those who want to reduce environmental impact and cost of living. Generally, an off-grid building must be able to supply energy and potable water for itself, as well as manage food, waste and wastewater.
Microgeneration is the small-scale production of heat or electric power from a "low carbon source," as an alternative or supplement to traditional centralized grid-connected power.
A stand-alone power system, also known as remote area power supply (RAPS), is an off-the-grid electricity system for locations that are not fitted with an electricity distribution system. Typical SAPS include one or more methods of electricity generation, energy storage, and regulation.
Dispatchable generation refers to sources of electricity that can be programmed on demand at the request of power grid operators, according to market needs. Dispatchable generators may adjust their power output according to an order. Non-dispatchable renewable energy sources such as wind power and solar photovoltaic (PV) power cannot be controlled by operators. Other types of renewable energy that are dispatchable without separate energy storage are hydroelectric, biomass, geothermal and ocean thermal energy conversion.
A load-following power plant, regarded as producing mid-merit or mid-priced electricity, is a power plant that adjusts its power output as demand for electricity fluctuates throughout the day. Load-following plants are typically in between base load and peaking power plants in efficiency, speed of start-up and shut-down, construction cost, cost of electricity and capacity factor.
India's solar power installed capacity was 89.43 GW AC as of 31 August 2024. India is the third largest producer of solar power globally.
Solar power, also known as solar electricity, is the conversion of energy from sunlight into electricity, either directly using photovoltaics (PV) or indirectly using concentrated solar power. Solar panels use the photovoltaic effect to convert light into an electric current. Concentrated solar power systems use lenses or mirrors and solar tracking systems to focus a large area of sunlight to a hot spot, often to drive a steam turbine.
A photovoltaic system, also called a PV system or solar power system, is an electric power system designed to supply usable solar power by means of photovoltaics. It consists of an arrangement of several components, including solar panels to absorb and convert sunlight into electricity, a solar inverter to convert the output from direct to alternating current, as well as mounting, cabling, and other electrical accessories to set up a working system. Many utility-scale PV systems use tracking systems that follow the sun's daily path across the sky to generate more electricity than fixed-mounted systems.
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.
The following outline is provided as an overview of and topical guide to solar energy:
Renewable energy sources such as solar, wind, tidal, hydro, biomass, and geothermal have become significant sectors of the energy market. The rapid growth of these sources in the 21st century has been prompted by increasing costs of fossil fuels as well as their environmental impact issues that significantly lowered their use.
The Australian Renewable Energy Agency (ARENA) is an independent agency of the Australian federal government, established in 2012 to manage Australia's renewable energy programs, with the objective of increasing supply and competitiveness of Australian renewable energy sources.
Energy in the Faroe Islands is produced primarily from imported fossil fuels, with further contributions from hydro and wind power. Oil products are the main energy source, mainly consumed by fishing vessels and sea transport. Electricity is produced by oil, hydropower and wind farms, mainly by SEV, which is owned by all the municipalities of the Faroe Islands. The Faroe Islands are not connected by power lines with continental Europe, and thus the archipelago cannot import or export electricity.
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↑ Garcia-Gonzalez, Javier; de la Muela, Rocío Moraga Ruiz; Santos, Luz Matres; Gonzalez, Alicia Mateo (22 April 2008). "Stochastic Joint Optimization of Wind Generation and Pumped-Storage Units in an Electricity Market". IEEE Transactions on Power Systems. 23 (2). IEEE: 460. Bibcode:2008ITPSy..23..460G. doi:10.1109/TPWRS.2008.919430. S2CID8309731.
↑ Bonnier Corporation (April 1983). "Popular Science". The Popular Science Monthly. Bonnier Corporation: 85, 86. ISSN0161-7370. Retrieved 17 April 2011.
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