GetWiki

{{Short description|Decentralised electricity generation}}{{Use dmy dates|date=November 2013}}(File:Staying big or getting smaller.jpg|thumb|500px|Centralized (left) vs distributed generation (right))Distributed generation, also distributed energy, on-site generation (OSG),WEB, On Site Generation: Learn more about our onsite renewable energy generation technologies,www.eonenergy.com/for-your-business/large-energy-users/manage-energy/on-site-generation, E.ON SE, 17 December 2015, 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).WEB,www.dg.history.vt.edu/ch1/introduction.html, Introduction to Distributed Generation, Virginia Tech, 2007, 23 October 2017, 10 December 2018,web.archive.org/web/20181210181948/https://www.dg.history.vt.edu/ch1/introduction.html, dead, Conventional power stations, such as coal-fired, gas, and nuclear powered plants, as well as hydroelectric dams and large-scale solar power stations, are centralized and often require electric energy to be transmitted over long distances. By contrast, DER systems are decentralized, modular, and more flexible technologies that are located close to the load they serve, albeit having capacities of only 10 megawatts (MW) or less. These systems can comprise multiple generation and storage components; in this instance, they are referred to as hybrid power systems.WEB,www.atulhost.com/empowering-the-future-with-distributed-energy-resources, Empowering the future with distributed energy resources, 2023, DER systems typically use renewable energy sources, including small hydro, biomass, biogas, solar power, wind power, and geothermal power, and increasingly play an important role for the electric power distribution system. A grid-connected device for electricity storage can also be classified as a DER system and is often called a distributed energy storage system (DESS).JOURNAL, Nadeem, Talha Bin, Siddiqui, Mubashir, Khalid, Muhammad, Asif, Muhammad, Distributed energy systems: A review of classification, technologies, applications, and policies, Energy Strategy Reviews, 2023, 48, 101096, 10.1016/j.esr.2023.101096, free, By means of an interface, DER systems can be managed and coordinated within a smart grid. Distributed generation and storage enables the collection of energy from many sources and may lower environmental impacts and improve the security of supply.One of the major issues with the integration of the DER such as solar power, wind power, etc. is the uncertain nature of such electricity resources. This uncertainty can cause a few problems in the distribution system: (i) it makes the supply-demand relationships extremely complex, and requires complicated optimization tools to balance the network, and (ii) it puts higher pressure on the transmission network,JOURNAL, Mohammadi Fathabad, Abolhassan, Cheng, Jianqiang, Pan, Kai, Qiu, Feng, 2020, Data-driven Planning for Renewable Distributed Generation in Distribution Systems,ieeexplore.ieee.org/document/9112707, IEEE Transactions on Power Systems, 35, 6, 4357–4368, 10.1109/TPWRS.2020.3001235, 225734643, 1558-0679, and (iii) it may cause reverse power flow from the distribution system to transmission system.JOURNAL, De Carne, Giovanni, Buticchi, Giampaolo, Zou, Zhixiang, Liserre, Marco, July 2018, Reverse Power Flow Control in a ST-Fed Distribution Grid, IEEE Transactions on Smart Grid, 9, 4, 3811–3819, 10.1109/TSG.2017.2651147, 49354817, 1949-3061,nbn-resolving.org/urn:nbn:de:gbv:8-publ-14890, Microgrids are modern, localized, small-scale grids,BOOK, Saleh, M., Esa, Y., Mhandi, Y., Brandauer, W., Mohamed, A., 2016 IEEE Industry Applications Society Annual Meeting, Design and implementation of CCNY DC microgrid testbed, October 2016, 1–7, 10.1109/IAS.2016.7731870, 978-1-4799-8397-1, 16464909,academicworks.cuny.edu/cgi/viewcontent.cgi?article=1722&context=cc_pubs, BOOK, Saleh, M. S., Althaibani, A., Esa, Y., Mhandi, Y., Mohamed, A. A., 2015 International Conference on Smart Grid and Clean Energy Technologies (ICSGCE), Impact of clustering microgrids on their stability and resilience during blackouts, October 2015, 195–200, 10.1109/ICSGCE.2015.7454295, 978-1-4673-8732-3, 25664994,academicworks.cuny.edu/cgi/viewcontent.cgi?article=1623&context=cc_pubs, contrary to the traditional, centralized electricity grid (macrogrid). Microgrids can disconnect from the centralized grid and operate autonomously, strengthen grid resilience, and help mitigate grid disturbances. They are typically low-voltage AC grids, often use diesel generators, and are installed by the community they serve. Microgrids increasingly employ a mixture of different distributed energy resources, such as solar hybrid power systems, which significantly reduce the amount of carbon emitted.{{TOC limit|3}}

Overview

Historically, central plants have been an integral part of the electric grid, in which large generating facilities are specifically located either close to resources or otherwise located far from populated load centers. These, in turn, supply the traditional transmission and distribution (T&D) grid that distributes bulk power to load centers and from there to consumers. These were developed when the costs of transporting fuel and integrating generating technologies into populated areas far exceeded the cost of developing T&D facilities and tariffs. Central plants are usually designed to take advantage of available economies of scale in a site-specific manner, and are built as “one-off”, custom projects.These economies of scale began to fail in the late 1960s and, by the start of the 21st century, Central Plants could arguably no longer deliver competitively cheap and reliable electricity to more remote customers through the grid, because the plants had come to cost less than the grid and had become so reliable that nearly all power failures originated in the grid. {{Citation needed|date=February 2012}} Thus, the grid had become the main driver of remote customers’ power costs and power quality problems, which became more acute as digital equipment required extremely reliable electricity.DOE; The Potential Benefits of Distributed Generation and Rate-Related Issues that May Impede Their Expansion; 2007.Lovins; Small Is Profitable: The Hidden Economic Benefits of Making Electrical Resources the Right Size; Rocky Mountain Institute, 2002. Efficiency gains no longer come from increasing generating capacity, but from smaller units located closer to sites of demand.Takahashi, et al; Policy Options to Support Distributed Resources; U. of Del., Ctr. for Energy & Env. Policy; 2005.Hirsch; 1989; cited in DOE, 2007.For example, coal power plants are built away from cities to prevent their heavy air pollution from affecting the populace. In addition, such plants are often built near collieries to minimize the cost of transporting coal. Hydroelectric plants are by their nature limited to operating at sites with sufficient water flow.Low pollution is a crucial advantage of combined cycle plants that burn natural gas. The low pollution permits the plants to be near enough to a city to provide district heating and cooling.Distributed energy resources are mass-produced, small, and less site-specific. Their development arose out of:

1. concerns over perceived externalized costs of central plant generation, particularly environmental concerns;
2. the increasing age, deterioration, and capacity constraints upon T&D for bulk power;
3. the increasing relative economy of mass production of smaller appliances over heavy manufacturing of larger units and on-site construction;
4. Along with higher relative prices for energy, higher overall complexity and total costs for regulatory oversight, tariff administration, and metering and billing.

Capital markets have come to realize that right-sized resources, for individual customers, distribution substations, or microgrids, are able to offer important but little-known economic advantages over central plants. Smaller units offered greater economies from mass-production than big ones could gain through unit size. These increased value—due to improvements in financial risk, engineering flexibility, security, and environmental quality—of these resources can often more than offset their apparent cost disadvantages.Lovins; Small Is Profitable: The Hidden Economic Benefits of Making Electrical Resources the Right Size; Rocky Mountain Institute; 2002 Distributed generation (DG), vis-à-vis central plants, must be justified on a life-cycle basis.Michigan (Citation pending) Unfortunately, many of the direct, and virtually all of the indirect, benefits of DG are not captured within traditional utility cash-flow accounting.While the levelized cost of DG is typically more expensive than conventional, centralized sources on a kilowatt-hour basis, this does not consider negative aspects of conventional fuels. The additional premium for DG is rapidly declining as demand increases and technology progresses,{{Citation needed|date=June 2013}}WEB,www.businessinsider.sg/solar-power-cost-decrease-2018-5/, One simple chart shows why an energy revolution is coming — and who is likely to come out on top, Berke, Jeremy, 2018-05-08, Business Insider Singapore, en-US, 2018-12-18, WEB,insideevs.com/bloomberg-predicts-rapidly-falling-battery-prices/, Bloomberg’s Latest Forecast Predicts Rapidly Falling Battery Prices, 2018-06-21, Inside EVs, en-US, 2018-12-18, ] and sufficient and reliable demand may bring economies of scale, innovation, competition, and more flexible financing, that could make DG clean energy part of a more diversified future.{{Citation needed|date=February 2012}} DG reduces the amount of energy lost in transmitting electricity because the electricity is generated very near where it is used, perhaps even in the same building. This also reduces the size and number of power lines that must be constructed.Typical DER systems in a feed-in tariff (FIT) scheme have low maintenance, low pollution and high efficiencies. In the past, these traits required dedicated operating engineers and large complex plants to reduce pollution. However, modern embedded systems can provide these traits with automated operation and renewable energy, such as solar, wind and geothermal. This reduces the size of power plant that can show a profit.

Grid parity

Grid parity occurs when an alternative energy source can generate electricity at a levelized cost (LCOE) that is less than or equal to the end consumer’s retail price. Reaching grid parity is considered to be the point at which an energy source becomes a contender for widespread development without subsidies or government support. Since the 2010s, grid parity for solar and wind has become a reality in a growing number of markets, including Australia, several European countries, and some states in the U.S.WEB ,

Technologies

Distributed energy resource (DER) systems are small-scale power generation or storage technologies (typically in the range of 1 kW to 10,000 kW)WEB , used to provide an alternative to or an enhancement of the traditional electric power system. DER systems typically are characterized by high initial capital costs per kilowattwww.NREL.gov Distributed Energy Resources Interconnection Systems: Technology Review and Research Needs, 2002 DER systems also serve as storage device and are often called Distributed energy storage systems (DESS).DER systems may include the following devices/technologies:

• Combined heat power (CHP),JOURNAL, Du, R., Robertson, P., 2017, Cost Effective Grid-Connected Inverter for a Micro Combined Heat and Power System, IEEE Transactions on Industrial Electronics, 64, 7, 5360–5367, 10.1109/TIE.2017.2677340, 1042325, 0278-0046,www.repository.cam.ac.uk/handle/1810/263361, also known as cogeneration or trigeneration
• Fuel cells
• Hybrid power systems (solar hybrid and wind hybrid systems)
• Micro combined heat and power (MicroCHP)
• Microturbines
• Photovoltaic systems (typically rooftop solar PV)
• Reciprocating engines
• Small wind power systems
• Stirling engines
• or a combination of the above. For example, hybrid photovoltaic, CHP and battery systems can provide full electric power for single family residences without extreme storage expenses.Kunal K. Shah, Aishwarya S. Mundada, Joshua M. Pearce. Performance of U.S. hybrid distributed energy systems: Solar photovoltaic, battery and combined heat and power. Energy Conversion and Management 105, pp. 71–80 (2015).

Cogeneration

Distributed cogeneration sources use steam turbines, natural gas-fired fuel cells, microturbines or reciprocating enginesGas engine cogeneration,www.clarke-energy.com, retrieved 9.12.2013 to turn generators. The hot exhaust is then used for space or water heating, or to drive an absorptive chillerWEB,www.buderus.de/Ueber_uns/Presse/Fachpresse/Anlagen_zur_Kraft_Waerme_Kopplung/Heiss_auf_kalt-2119341.html, Heiß auf kalt, 15 May 2015, 18 May 2015,www.buderus.de/Ueber_uns/Presse/Fachpresse/Anlagen_zur_Kraft_Waerme_Kopplung/Heiss_auf_kalt-2119341.html," title="web.archive.org/web/20150518102403www.buderus.de/Ueber_uns/Presse/Fachpresse/Anlagen_zur_Kraft_Waerme_Kopplung/Heiss_auf_kalt-2119341.html,">web.archive.org/web/20150518102403www.buderus.de/Ueber_uns/Presse/Fachpresse/Anlagen_zur_Kraft_Waerme_Kopplung/Heiss_auf_kalt-2119341.html, dead, Trigeneration with gas engines,www.clarke-energy.com, retrieved 9.12.2013 for cooling such as air-conditioning. In addition to natural gas-based schemes, distributed energy projects can also include other renewable or low carbon fuels including biofuels, biogas, landfill gas, sewage gas, coal bed methane, syngas and associated petroleum gas.Gas engine applications, weblink, retrieved 9 December 2013Delta-ee consultants stated in 2013 that with 64% of global sales, the fuel cell micro combined heat and power passed the conventional systems in sales in 2012.REPORT,www.fuelcelltoday.com/media/1889744/fct_review_2013.pdf, The fuel cell industry review 2013, FuelCellToday.com,www.fuelcelltoday.com/media/1889744/fct_review_2013.pdf," title="web.archive.org/web/20131007223834www.fuelcelltoday.com/media/1889744/fct_review_2013.pdf,">web.archive.org/web/20131007223834www.fuelcelltoday.com/media/1889744/fct_review_2013.pdf, 7 October 2013, 20.000 units were sold in Japan in 2012 overall within the Ene Farm project. With a Lifetime of around 60,000 hours for PEM fuel cell units, which shut down at night, this equates to an estimated lifetime of between ten and fifteen years.WEB,www.fuelcelltoday.com/analysis/analyst-views/2013/13-02-27-latest-developments-in-the-ene-farm-scheme, Latest Developments in the Ene-Farm Scheme, 15 May 2015, For a price of $22,600 before installation.WEB,panasonic.co.jp/corp/news/official.data/data.dir/2013/01/en130117-5/en130117-5.html, Launch of New ‘Ene-Farm’ Home Fuel Cell Product More Affordable and Easier to Install - Headquarters News - Panasonic Newsroom Global, 15 May 2015, For 2013 a state subsidy for 50,000 units is in place.In addition, molten carbonate fuel cell and solid oxide fuel cells using natural gas, such as the ones from FuelCell Energy and the Bloom energy server, or waste-to-energy processes such as the Gate 5 Energy System are used as a distributed energy resource.

Solar power

{{Further|Photovoltaic system}}Photovoltaics, by far the most important solar technology for distributed generation of solar power, uses solar cells assembled into solar panels to convert sunlight into electricity. It is a fast-growing technology doubling its worldwide installed capacity every couple of years. PV systems range from distributed, residential, and commercial rooftop or building integrated installations, to large, centralized utility-scale photovoltaic power stations.The predominant PV technology is crystalline silicon, while thin-film solar cell technology accounts for about 10 percent of global photovoltaic deployment.WEB , {{rp|18,19}} In recent years, PV technology has improved its sunlight to electricity conversion efficiency, reduced the installation cost per watt as well as its energy payback time (EPBT) and levelised cost of electricity (LCOE), and has reached grid parity in at least 19 different markets in 2014.WEB , As most renewable energy sources and unlike coal and nuclear, solar PV is variable and non-dispatchable, but has no fuel costs, operating pollution, as well as greatly reduced mining-safety and operating-safety issues. It produces peak power around local noon each day and its capacity factor is around 20 percentwww.academia.edu, Janet Marsdon Distributed Generation Systems:A New Paradigm for Sustainable Energy

Wind power

Wind turbines can be distributed energy resources or they can be built at utility scale. These have low maintenance and low pollution, but distributed wind unlike utility-scale wind has much higher costs than other sources of energy.WEB, NREL: Energy Analysis - Distributed Generation Energy Technology Capital Costs,www.nrel.gov/analysis/tech_cost_dg.html, www.nrel.gov, 2015-10-31, As with solar, wind energy is variable and non-dispatchable. Wind towers and generators have substantial insurable liabilities caused by high winds, but good operating safety. Distributed generation from wind hybrid power systems combines wind power with other DER systems. One such example is the integration of wind turbines into solar hybrid power systems, as wind tends to complement solar because the peak operating times for each system occur at different times of the day and year.

Hydro power

Hydroelectricity is the most widely used form of renewable energy and its potential has already been explored to a large extent or is compromised due to issues such as environmental impacts on fisheries, and increased demand for recreational access. However, using modern 21st century technology, such as wave power, can make large amounts of new hydropower capacity available, with minor environmental impact.Modular and scalable Next generation kinetic energy turbines can be deployed in arrays to serve the needs on a residential, commercial, industrial, municipal or even regional scale. Microhydro kinetic generators neither require dams nor impoundments, as they utilize the kinetic energy of water motion, either waves or flow. No construction is needed on the shoreline or sea bed, which minimizes environmental impacts to habitats and simplifies the permitting process. Such power generation also has minimal environmental impact and non-traditional microhydro applications can be tethered to existing construction such as docks, piers, bridge abutments, or similar structureswww.academia.edu, Janet Marsdon Distributed Generation Systems:A New Paradigm for Sustainable Energy, pp. 8, 9

Waste-to-energy

Municipal solid waste (MSW) and natural waste, such as sewage sludge, food waste and animal manure will decompose and discharge methane-containing gas that can be collected and used as fuel in gas turbines or micro turbines to produce electricity as a distributed energy resource. Additionally, a California-based company, Gate 5 Energy Partners, Inc. has developed a process that transforms natural waste materials, such as sewage sludge, into biofuel that can be combusted to power a steam turbine that produces power. This power can be used in lieu of grid-power at the waste source (such as a treatment plant, farm or dairy).

Energy storage

A distributed energy resource is not limited to the generation of electricity but may also include a device to store distributed energy (DE)www.smartgrid.gov Lexicon Distributed Energy Resource {{Webarchive|url=https://web.archive.org/web/20171206030230www.smartgrid.gov/ |date=6 December 2017 }} Distributed energy storage systems (DESS) applications include several types of battery, pumped hydro, compressed air, and thermal energy storage.{{rp|42}} Access to energy storage for commercial applications is easily accessible through programs such as energy storage as a service (ESaaS).

PV storage

Vehicle-to-grid

Flywheels

, WEB ,

Integration with the grid

For reasons of reliability, distributed generation resources would be interconnected to the same transmission grid as central stations. Various technical and economic issues occur in the integration of these resources into a grid. Technical problems arise in the areas of power quality, voltage stability, harmonics, reliability, protection, and control.WEB, Contribution to Bulk System Control and Stability by Distributed Energy Resources connected at Distribution Network,resourcecenter.ieee-pes.org/pes/product/technical-publications/PESTRPDFMRH0022, IEEE PES Technical Report, 15 January 2017, Tomoiagă, B.; ChindriÅŸ, M.; Sumper, A.; Sudria-Andreu, A.; Villafafila-Robles, R. Pareto Optimal Reconfiguration of Power Distribution Systems Using a Genetic Algorithm Based on NSGA-II. Energies 2013, 6, 1439-1455. Behavior of protective devices on the grid must be examined for all combinations of distributed and central station generation.P. Mazidi, G. N. Sreenivas; Reliability Assessment of A Distributed Generation Connected Distribution System; International Journal of Power System Operation and Energy Management(IJPSOEM), Nov. 2011 A large scale deployment of distributed generation may affect grid-wide functions such as frequency control and allocation of reserves.Math H. Bollen, Fainan Hassan Integration of Distributed Generation in the Power System, John Wiley & Sons, 2011{{ISBN|1-118-02901-1}}, pages v-x As a result, smart grid functions, virtual power plants Decision Making Tool for Virtual Power Plants Considering Midterm Bilateral ContractsThe Design of a Risk-hedging Tool for Virtual Power Plants via Robust Optimization ApproachA Medium-Term Coalition-Forming Model of Heterogeneous DERs for a Commercial Virtual Power Plant and grid energy storage such as power to gas stations are added to the grid. Conflicts occur between utilities and resource managing organizations.WEB, Bandyk, Matthew, Propelling the transition: The battle for control of virtual power plants is just beginning,www.utilitydive.com/news/propelling-the-transition-the-battle-for-control-of-virtual-power-plants-i/581875/, Utility Dive,web.archive.org/web/20200819022737/https://www.utilitydive.com/news/propelling-the-transition-the-battle-for-control-of-virtual-power-plants-i/581875/, 19 August 2020, 18 August 2020, live, Each distributed generation resource has its own integration issues. Solar PV and wind power both have intermittent and unpredictable generation, so they create many stability issues for voltage and frequency. These voltage issues affect mechanical grid equipment, such as load tap changers, which respond too often and wear out much more quickly than utilities anticipated.JOURNAL, Agalgaonkar, Y.P., etal, Distribution Voltage Control Considering the Impact of PV Generation on Tap Changers and Autonomous Regulators, IEEE Transactions on Power Systems, 16 September 2013, 29, 1, 182–192, 10.1109/TPWRS.2013.2279721, 10044/1/12201, 16686085, free, Also, without any form of energy storage during times of high solar generation, companies must rapidly increase generation around the time of sunset to compensate for the loss of solar generation. This high ramp rate produces what the industry terms the duck curve that is a major concern for grid operators in the future.WEB, What the Duck Curve Tells Us About Managing A Green Grid,www.caiso.com/Documents/FlexibleResourcesHelpRenewables_FastFacts.pdf, caiso.com, California ISO, 29 April 2015, Storage can fix these issues if it can be implemented. Flywheels have shown to provide excellent frequency regulation.BOOK, Lazarewicz, Matthew, Rojas, Alex, IEEE Power Engineering Society General Meeting, 2004, Grid frequency regulation by recycling electrical energy in flywheels, Power Engineering Society General Meeting, 2, 10 June 2004, 2038–2042, 10.1109/PES.2004.1373235, 0-7803-8465-2, 20032334, Also, flywheels are highly cyclable compared to batteries, meaning they maintain the same energy and power after a significant amount of cycles( on the order of 10,000 cycles).WEB, Flywheels,energystorage.org/energy-storage/technologies/flywheels, Energy Storage Association, Short term use batteries, at a large enough scale of use, can help to flatten the duck curve and prevent generator use fluctuation and can help to maintain voltage profile.WEB, Lazar, Jim, Teaching the “Duck” to Fly,www.ripuc.ri.gov/eventsactions/docket/4443-EERMC-Presentation2_5-8-14.pdf, RAP, 29 April 2015, However, cost is a major limiting factor for energy storage as each technique is prohibitively expensive to produce at scale and comparatively not energy dense compared to liquid fossil fuels. Finally, another necessary method of aiding in integration of photovoltaics for proper distributed generation is in the use of intelligent hybrid inverters. Intelligent hybrid inverters store energy when there is more energy production than consumption. When consumption is high, these inverters provide power relieving the distribution system.WEB, Smart Grid, Smart Inverters for a Smart Energy Future,www.nrel.gov/state-local-tribal/blog/posts/smart-grid-smart-inverters-for-a-smart-energy-future.html, National Renewable Energy Labortatory, Another approach does not demand grid integration: stand alone hybrid systems.

Mitigating voltage and frequency issues of DG integration

There have been some efforts to mitigate voltage and frequency issues due to increased implementation of DG. Most notably, IEEE 1547 sets the standard for interconnection and interoperability of distributed energy resources. IEEE 1547 sets specific curves signaling when to clear a fault as a function of the time after the disturbance and the magnitude of the voltage irregularity or frequency irregularity.REPORT, Performance of Distributed Energy and Resources During and After System Disturbance on, December 2013, Voltage issues also give legacy equipment the opportunity to perform new operations. Notably, inverters can regulate the voltage output of DGs. Changing inverter impedances can change voltage fluctuations of DG, meaning inverters have the ability to control DG voltage output.REPORT, Advanced Control Technologies for Distribution Grid Voltage and Stability With Electric Vehicles and Distributed Generation on, March 2015, 48–50, To reduce the effect of DG integration on mechanical grid equipment, transformers and load tap changers have the potential to implement specific tap operation vs. voltage operation curves mitigating the effect of voltage irregularities due to DG. That is, load tap changers respond to voltage fluctuations that last for a longer period than voltage fluctuations created from DG equipment.REPORT, Optimal OLTC Voltage Control Scheme High Solar Penetrations on, April 2018, 7–9,

Stand alone hybrid systems

It is now possible to combine technologies such as photovoltaics, batteries and cogen to make stand alone distributed generation systems.JOURNAL, Shah, Kunal K., Mundada, Aishwarya S., Pearce, Joshua M., 2015, Performance of U.S. hybrid distributed energy systems: Solar photovoltaic, battery and combined heat and power,www.academia.edu/14674492, Energy Conversion and Management, 105, 71–80, 10.1016/j.enconman.2015.07.048, 2015ECM...105...71S, 107189983, Recent work has shown that such systems have a low levelized cost of electricity.JOURNAL, Mundada, Aishwarya, Shah, Kunal, Pearce, Joshua M., 2016, Levelized cost of electricity for solar photovoltaic, battery and cogen hybrid systems,www.academia.edu/20141118, Renewable and Sustainable Energy Reviews, 57, 692–703, 10.1016/j.rser.2015.12.084, 110914380, Many authors now think that these technologies may enable a mass-scale grid defection because consumers can produce electricity using off grid systems primarily made up of solar photovoltaic technology.Kumagai, J., 2014. The rise of the personal power plant. IEEE Spectrum,51(6), pp.54-59.Abhilash Kantamneni, Richelle Winkler, Lucia Gauchia, Joshua M. Pearce, free open access Emerging economic viability of grid defection in a northern climate using solar hybrid systems. Energy Policy 95, 378–389 (2016). doi: 10.1016/j.enpol.2016.05.013Khalilpour, R. and Vassallo, A., 2015. Leaving the grid: An ambition or a real choice?. Energy Policy, 82, pp.207-221. For example, the Rocky Mountain Institute has proposed that there may wide scale grid defection.The Economics of Grid Defection - Rocky Mountain Institute

Cost factors

Cogenerators are also more expensive per watt than central generators.{{citation needed|date=November 2013}} They find favor because most buildings already burn fuels, and the cogeneration can extract more value from the fuel . Local production has no electricity transmission losses on long distance power lines or energy losses from the Joule effect in transformers where in general 8-15% of the energy is lostWEB,blog.schneider-electric.com/energy-management-energy-efficiency/2013/03/25/how-big-are-power-line-losses/, How big are Power line losses?, Schneider Electric Blog, 15 May 2015, 25 March 2013, (see also cost of electricity by source).Some larger installations utilize combined cycle generation. Usually this consists of a gas turbine whose exhaust boils water for a steam turbine in a Rankine cycle. The condenser of the steam cycle provides the heat for space heating or an absorptive chiller. Combined cycle plants with cogeneration have the highest known thermal efficiencies, often exceeding 85%.In countries with high pressure gas distribution, small turbines can be used to bring the gas pressure to domestic levels whilst extracting useful energy. If the UK were to implement this countrywide an additional 2-4 GWe would become available. (Note that the energy is already being generated elsewhere to provide the high initial gas pressure - this method simply distributes the energy via a different route.)

Microgrid

A microgrid is a localized grouping of electricity generation, energy storage, and loads that normally operates connected to a traditional centralized grid (macrogrid). This single point of common coupling with the macrogrid can be disconnected. The microgrid can then function autonomously.Stan Mark Kaplan, Fred Sissine, (ed.) Smart grid: modernizing electric power transmission and distribution... The Capitol Net Inc, 2009, {{ISBN|1-58733-162-4}}, page 217 Generation and loads in a microgrid are usually interconnected at low voltage and it can operate in DC, AC, or the combination of both. From the point of view of the grid operator, a connected microgrid can be controlled as if it were one entity.Microgrid generation resources can include stationary batteries, fuel cells, solar, wind, or other energy sources. The multiple dispersed generation sources and ability to isolate the microgrid from a larger network would provide highly reliable electric power. Produced heat from generation sources such as microturbines could be used for local process heating or space heating, allowing flexible trade off between the needs for heat and electric power.Micro-grids were proposed in the wake of the July 2012 India blackout:WEB,www.moneycontrol.com/smementor/mentorade/starting-up/power-crisisgrid-collapse-is-it-time-to-think--739976.html, Power crisis and grid collapse: Is it time to think, 15 May 2015,

• Small micro-grids covering 30–50 km radius
• Small power stations of 5–10 MW to serve the micro-grids
• Generate power locally to reduce dependence on long distance transmission lines and cut transmission losses.

Micro-grids have seen implementation in a number of communities over the world. For example, Tesla has implemented a solar micro-grid in the Samoan island of Ta’u, powering the entire island with solar energy.NEWS,www.theverge.com/2016/11/22/13712750/tesla-microgrid-tau-samoa, Tesla powers a whole island with solar to show off its energy chops, The Verge, 2018-03-09, This localized production system has helped save over {{convert|100,000|usgal|m3|order=flip}} of diesel fuel. It is also able to sustain the island for three whole days if the sun were not to shine at all during that period.NEWS,news.nationalgeographic.com/2017/02/tau-american-samoa-solar-power-microgrid-tesla-solarcity/,news.nationalgeographic.com/2017/02/tau-american-samoa-solar-power-microgrid-tesla-solarcity/," title="web.archive.org/web/20170225040142news.nationalgeographic.com/2017/02/tau-american-samoa-solar-power-microgrid-tesla-solarcity/,">web.archive.org/web/20170225040142news.nationalgeographic.com/2017/02/tau-american-samoa-solar-power-microgrid-tesla-solarcity/, dead, 25 February 2017, How a Pacific Island Changed From Diesel to 100% Solar Power, 2017-02-23, 2018-03-09, This is a great example of how micro-grid systems can be implemented in communities to encourage renewable resource usage and localized production.To plan and install Microgrids correctly, engineering modelling is needed. Multiple simulation tools and optimization tools exist to model the economic and electric effects of Microgrids. A widely used economic optimization tool is the Distributed Energy Resources Customer Adoption Model (DER-CAM) from Lawrence Berkeley National Laboratory. Another frequently used commercial economic modelling tool is Homer Energy, originally designed by the National Renewable Laboratory. There are also some power flow and electrical design tools guiding the Microgrid developers. The Pacific Northwest National Laboratory designed the public available GridLAB-D tool and the Electric Power Research Institute (EPRI) designed OpenDSS to simulate the distribution system (for Microgrids). A professional integrated DER-CAM and OpenDSS version is available via BankableEnergy {{Webarchive|url=https://web.archive.org/web/20180711022032www.bankableenergy.com/ |date=11 July 2018 }}. A European tool that can be used for electrical, cooling, heating, and process heat demand simulation is EnergyPLAN from the Aalborg University, Denmark.

Communication in DER systems

• IEC 61850-7-420 is published by IEC TC 57: Power systems management and associated information exchange. It is one of the IEC 61850 standards, some of which are core Standards required for implementing smart grids. It uses communication services mapped to MMS as per IEC 61850-8-1 standard.
• OPC is also used for the communication between different entities of DER system.
• Institute of Electrical and Electronics Engineers IEEE 2030.7 microgrid controller standard. That concept relies on 4 blocks: a) Device Level control (e.g. Voltage and Frequency Control), b) Local Area Control (e.g. data communication), c) Supervisory (software) controller (e.g. forward looking dispatch optimization of generation and load resources), and d) Grid Layer (e.g. communication with utility).
• A wide variety of complex control algorithms exist, making it difficult for small and residential Distributed Energy Resource (DER) users to implement energy management and control systems. Especially, communication upgrades and data information systems can make it expensive. Thus, some projects try to simplify the control of DER via off-the shelf products and make it usable for the mainstream (e.g. using a Raspberry Pi).BOOK, Fürst, Jonathan, Gawinowski, Nik, Buettrich, Sebastian, Bonnet, Philippe, 2013 IEEE Global Humanitarian Technology Conference (GHTC), COSMGrid: Configurable, off-the-shelf micro grid, 2013-09-25,www.researchgate.net/publication/259157235, 96–101, 10.1109/GHTC.2013.6713662, 978-1-4799-2402-8, 19202084, WEB,www.cet.or.at/pdf_files/Paspberry%20Pi%20Microgrid%20Controller.pdf, A flexible low cost PV/EV microgrid controller concept based on a Raspberry Pi, Stadler, Michael, 2018, Center for Energy and innovative Technologies,

Legal requirements for distributed generation

In 2010 Colorado enacted a law requiring that by 2020 that 3% of the power generated in Colorado utilize distributed generation of some sort.“Going Solar Is Harder Than It Looks, a Valley Finds” article by Kirk Johnson in The New York Times 3 June 2010“Colorado Increases Renewables Requirements” blog by Kate Galbraith on NYTimes.Com 22 March 2010On 11 October 2017, California Governor Jerry Brown signed into law a bill, SB 338, that makes utility companies plan “carbon-free alternatives to gas generation” in order to meet peak demand. The law requires utilities to evaluate issues such as energy storage, efficiency, and distributed energy resources.NEWS,www.utilitydive.com/news/california-gov-brown-signs-bill-directing-utilities-to-plan-storage-ders/507116/, California Gov. Brown signs bill directing utilities to plan storage, DERs for peak demand, Bade, Gavin, 2017-10-12, Utility Dive, 2017-10-18, en-US,

See also

{{Div col start|colwidth=26em}}

• Autonomous building
• Demand response
• Energy harvesting
• Energy storage as a service (ESaaS)
• Electranet
• Electric power transmission
• Electricity generation
• Electricity market
• Electricity retailing
• Energy demand management
• Energy efficiency
• Energy storage
• Flywheel energy storage
• Future energy development
• Green power superhighway
• Grid-tied electrical system
• Hydrogen station
• IEEE 1547 (Standard for Interconnecting DistributedResources with Electric Power Systems)
• Islanding
• Local flexibility markets
• Microgeneration
• Net metering
• Peak shaving
• Relative cost of electricity generated by different sources
• Renewable energy development
• Smart meter
• Smart power grid
• Solar Guerrilla
• Stand-alone power system
• Sustainable community energy system
• Trigeneration
• World Alliance for Decentralized Energy

{{Div col end}}

References

{{Reflist}}

Further reading

• JOURNAL, Brass, J. N., Carley, S., MacLean, L. M., Baldwin, E., Power for Development: A Review of Distributed Generation Projects in the Developing World, 10.1146/annurev-environ-051112-111930, Annual Review of Environment and Resources, 37, 107–136, 2012, free,
• Gies, Erica. Making the Consumer an Active Participant in the Grid, The New York Times, 29 November 2010. Discusses distributed generation and the U.S. Federal Energy Regulatory Commission.
• BOOK, Power from the people : how to organize, finance, and launch local energy projects

,

External links

{{Div col start|colwidth=30em}}

• MIGRIDS -Worldwide Business and Marketing Microgrid Directory
• The UK District Energy Association - advocating the construction of locally distributed energy networks
• www.newrules.org/electricity/planningfordg.html" title="web.archive.org/web/20030622211043www.newrules.org/electricity/planningfordg.html">Decentralized Power as Part of Local and Regional Plans
• IEEE P1547 Draft Standard for Interconnecting Distributed Resources with Electric Power Systems
• World Alliance for Decentralized Energy
• The iDEaS project by University of Southampton on Decentralised Energy
• Biofuels and gas pressure energy recovery
• Microgrids projects and DER Optimization Model at Berkeley Lab
• DERlab
• Center for Energy and innovative Technologies
• ezine.pk/?Decentralized-Power-System-DPS-in-Pakistan&id=381" title="web.archive.org/web/20130610130954ezine.pk/?Decentralized-Power-System-DPS-in-Pakistan&id=381">Decentralized Power System (DPS) in Pakistan
• Distributed Generation—Educational Module, Virginia Tech {{Webarchive|url=https://web.archive.org/web/20150715224658www.dg.history.vt.edu/index.html |date=15 July 2015 }}
• What are distributed energy resources (DER) and how do they work?, Australian Renewable Energy Agency (ARENA).

{{Div col end}}{{Electricity generation}}{{Authority control}}