View source for Micro combined heat and power

{{Short description|Small-scale generation of heat and power}}
{{technical|date=August 2015}}

'''Micro combined heat and power''', '''micro-CHP''', '''μCHP''' or '''mCHP''' is an extension of the idea of [[cogeneration]] to the single/multi family home or small office building in the range of up to 50 [[Kilowatt|kW]].<ref name=":0">{{Cite web|url=https://eur-lex.europa.eu/eli/dir/2012/27/oj |title=DIRECTIVE 2012/27/EU on energy efficiency, Article 2(39) |website=eur-lex.europa.eu|language=en|date=2012-10-25|access-date=2017-08-11}}</ref> Usual technologies for the production of heat and power in one common process are e.g. [[internal combustion engine]]s, [[Microturbine|micro gas turbines]], [[stirling engine]]s or [[fuel cell]]s.

Local generation has the potential for a higher efficiency than traditional grid-level generators since it lacks the 8-10% energy losses from transporting [[electricity]] over long distances. It also lacks the 10–15% energy losses from [[District heating|heat transport]] in heating networks due to the difference between the thermal energy carrier (hot water) and the colder external environment.

The most common systems use natural gas as their primary energy source and emit [[Carbon dioxide in Earth's atmosphere|carbon dioxide]]; nevertheless the [[Carnot method#Performance factor of energy conversion|effective efficiency]] of CHP heat production is much higher than of a condensing boiler, and thus reducing emissions and fuel costs.

== Overview ==
A micro-CHP system usually contains a small [[heat engine]] as a prime mover used to rotate a generator which provides [[electric power]], while simultaneously utilizing the waste heat from the prime mover for an individual building's [[space heating]] and the provision of [[water heating|hot domestic water]].<ref>{{Cite book|url=https://www.springer.com/us/book/9783540255826|title=Micro Cogeneration - Towards Decentralized Energy Systems {{!}} Martin Pehnt {{!}} Springer|year=2006|publisher=Springer|doi=10.1007/3-540-30821-0|isbn=9783540255826|language=en}}</ref> 
With [[fuel cell]]s there is no rotating machinery, but the [[Glossary of fuel cell terms#Stack|fuel cell's stack]] and where applicable also the [[Steam reforming#For fuel cells|reformer]] will provide useful heat. The stack does generate DC power which is converted by DC/AC inverter into mains voltage. Micro-CHP is defined by the EU as less than 50&nbsp;kW electrical power output,<ref name=":0" /> however, others have more restrictive definitions, all the way down to <5 kWe.<ref>{{Cite journal|last1=De Paepe|first1=Michel|last2=D’Herdt|first2=Peter|last3=Mertens|first3=David|date=2006-11-01|title=Micro-CHP systems for residential applications|journal=Energy Conversion and Management|volume=47|issue=18|pages=3435–3446|doi=10.1016/j.enconman.2005.12.024|bibcode=2006ECM....47.3435D }}</ref>

A micro-CHP generator may primarily follow heat demand, delivering [[electricity]] as the by-product, or may follow electrical demand to [[electricity generation|generate electricity]], with heat as the by-product. When used primarily for heating, micro-CHP systems may generate more electricity than is instantaneously being demanded; the surplus is then fed into the grid.

The purpose of cogeneration is to make use of more of the chemical energy in the fuel. The reason for using CHP systems is that large [[thermal power plant]]s which generate electric power by burning fuel produce between 40% and 60% low-temperature [[waste heat]], due to [[Carnot's theorem (thermodynamics)|Carnot's theorem]].<ref>{{Cite book|title=Thermodynamics: An Engineering Approach |last1=Çengel |first1=Yunus A. |last2=Boles |first2=Michael A. |publisher=McGraw-Hill Education |isbn=978-0073398174|edition=Eighth|location=New York|oclc=869741544|date = 2014-01-07}}</ref> The temperature produced by this waste heat (around 80&nbsp;°C - 150&nbsp;°C) does allow it to be used for space heating purposes, therefore in some urban areas district heating networks have been installed. Heat networks have a limited extent, as it is not economical to transport heat long distances due to heat loss from the pipes, and it will not reach into areas of low population density, or else revenues per [[CAPEX]] will go down. Where no district heating is possible due to low heat demand density or because the local utility has not invested in costly heat networks, this thermal energy is usually wasted via [[cooling tower]]s or discharged into rivers, lakes or the sea.

Micro CHP systems allow highly efficient cogeneration while using the waste heat even if the served heat load is rather low. This allows cogeneration to be used outside population centers, or even if there is no district heating network. It is efficient to generate the electricity near the place where the heat can also be used. Small power plants (μCHP) are located in individual buildings, where the heat can be used to support the heating system and recharge the hot domestic water tank, thus saving heating oil or heating gas. CHP systems are able to increase the total energy utilization of primary energy sources. Thus CHP has been steadily gaining popularity in all sectors of the energy economy, due to the increased costs of electricity and fuel, particularly fossil fuels, and due to environmental concerns, particularly [[climate change]].<ref>{{cite journal|last1=Notter|first1=Dominic A.|last2=Kouravelou|first2=Katerina|last3=Karachalios|first3=Theodoros|last4=Daletou|first4=Maria K.|last5=Haberland|first5=Nara Tudela|title=Life cycle assessment of PEM FC applications: electric mobility and μ-CHP|journal=Energy Environ. Sci.|date=2015|volume=8|issue=7|pages=1969–1985|doi=10.1039/C5EE01082A}}</ref>

In a traditional [[power plant]] delivering electricity to consumers, about 34.4% of the primary energy of the input fuel, such as [[coal]], [[natural gas]], [[nuclear power|uranium]], [[petroleum]], [[solar thermal]], or [[biomass]], reaches the consumer via electricity,<ref>{{Cite web|url=https://www.eia.gov/electricity/state/|title=State Electricity Profiles - Energy Information Administration|website=www.eia.gov|language=en|access-date=2017-08-11}}</ref> although the efficiency can be 20% for very old plants and 45% for newer gas plants. In contrast, a CHP system converts 15%–42% of the primary heat to electricity, and most of the remaining heat is captured for [[water heating|hot water]] or [[space heating]]. In total, over 90% of the heat from the primary energy source (LHV based) can be used when heat production does not exceed the thermal demand.<ref>{{Cite journal|last1=Rosato|first1=A.|last2=Sibilio|first2=S.|date=2012-12-01|title=Calibration and validation of a model for simulating thermal and electric performance of an internal combustion engine-based micro-cogeneration device|journal=Applied Thermal Engineering|volume=45|pages=79–98|doi=10.1016/j.applthermaleng.2012.04.020|bibcode=2012AppTE..45...79R }}</ref><ref>{{Cite book|title=Experimental investigation of residential cogeneration devices and calibration of Annex 42 models : a report of Subtask B of FC+COGEN-SIM, the Simulation of Building-1ntegrated Fuel Cell and Other Cogeneration Systems, Annex 42 of the International Energy Agency Energy Conservation in Buildings and Community Systems Programme|date=2007|publisher=[Natural Resources Canada]|others=Beausoleil-Morrison, Ian., Arndt, Ulli., Canada. Natural Resources Canada., IEA Energy Conservation in Buildings & Community Systems Programme. Annex 42--Simulation of Building-Integrated Fuel Cell and Other Cogeneration Systems.|isbn=9780662475231|location=[Ottawa]|oclc=226302449}}</ref><ref>{{Cite journal|last1=de Santoli|first1=Livio|last2=Basso|first2=Gianluigi Lo|last3=Albo|first3=Angelo|last4=Bruschi|first4=Daniele|last5=Nastasi|first5=Benedetto|date=2015-12-01|title=Single Cylinder Internal Combustion Engine Fuelled with H2NG Operating as Micro-CHP for Residential Use: Preliminary Experimental Analysis on Energy Performances and Numerical Simulations for LCOE Assessment|journal=Energy Procedia|series=69th Conference of the Italian Thermal Engineering Association, ATI 2014|volume=81|pages=1077–1089|doi=10.1016/j.egypro.2015.12.130|url=https://iris.uniroma1.it/bitstream/11573/841857/1/DeSantoli_single_2015.pdf|doi-access=free}}</ref><ref>{{Cite journal|last1=Roselli|first1=Carlo|last2=Sasso|first2=Maurizio|last3=Sibilio|first3=Sergio|last4=Tzscheutschler|first4=Peter|date=2011-04-01|title=Experimental analysis of microcogenerators based on different prime movers|journal=Energy and Buildings|volume=43|issue=4|pages=796–804|doi=10.1016/j.enbuild.2010.11.021|bibcode=2011EneBu..43..796R }}</ref><ref>{{Cite journal|last=Thomas|first=Bernd|date=March 2008|title=Benchmark Testing of Micro-CHP units|journal=Applied Thermal Engineering|volume=28|issue=16|pages=2049–2054|doi=10.1016/j.applthermaleng.2008.03.010|bibcode=2008AppTE..28.2049T }}</ref>

Since the year 2000, micro-CHP has become cost effective in many markets around the world, due to rising energy costs. The development of micro-CHP systems has also been facilitated by recent technological developments of small heat engines. This includes improved performance and cost-effectiveness of [[fuel cell]]s, [[Stirling engine]]s, [[steam engines]], [[gas turbines]], [[diesel engine]]s and [[Otto engine]]s.

Combined heat and power (CHP) systems for homes or small commercial buildings are usually fueled by [[natural gas]] to produce electricity and heat.<ref name=":1">{{Cite journal|last1=Angrisani|first1=G.|last2=Roselli|first2=C.|last3=Sasso|first3=M.|date=2012-08-01|title=Distributed microtrigeneration systems|journal=Progress in Energy and Combustion Science|volume=38|issue=4|pages=502–521|doi=10.1016/j.pecs.2012.02.001|bibcode=2012PECS...38..502A }}</ref> If no access to the natural gas network is available, which in general is the cheapest alternative, [[Liquefied petroleum gas|LPG]], [[Liquefied natural gas|LNG]] or heating fuel (diesel) might be an alternative.
The [[PEMFC]] fuel cell mCHP operates at low temperatures (50 to 100&nbsp;°C) and needs high purity hydrogen. It is prone to contamination; changes are made to operate at higher temperatures and improvements on the fuel reformer. The [[SOFC]] fuel cell mCHP operates at a high temperature (500 to 1,000&nbsp;°C) and can handle different fuel sources well, but the high temperature requires expensive materials to handle it; changes are made to operate at a lower temperature. Because of the higher temperature the SOFC in general has a longer start-up time and needs continuous heat output even at times when there is no thermal demand.

CHP systems linked to [[absorption chiller]]s can use waste heat for [[refrigeration]].<ref>[https://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/tri-generation_fountainvalley.pdf Tri-Generation success story] {{webarchive |url=https://web.archive.org/web/20160304074647/https://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/tri-generation_fountainvalley.pdf |date=March 4, 2016 }}</ref>

A 2013 UK report from Ecuity Consulting stated that MCHP is the most cost-effective method of utilizing gas to generate energy at the domestic level.<ref>[http://www.ecuity.com/wp-content/uploads/2013/03/The-role-of-micro-CHP-in-a-smart-energy-world.pdf The role of micro CHP in a smart energy world] {{webarchive |url=https://web.archive.org/web/20160304072549/http://www.ecuity.com/wp-content/uploads/2013/03/The-role-of-micro-CHP-in-a-smart-energy-world.pdf |date=March 4, 2016 }}</ref><ref>[http://www.renewableenergyfocus.com/view/31489/micro-chp-report-powers-heated-discussion-about-uk-energy-future/ Micro CHP report powers heated discussion about UK energy future] {{webarchive |url=https://web.archive.org/web/20160320101136/http://www.renewableenergyfocus.com/view/31489/micro-chp-report-powers-heated-discussion-about-uk-energy-future/ |date=March 20, 2016 }}</ref>

The fuel cell industry review stated in 2013 that with 64% of global sales the fuel cell micro-combined heat and power had passed the conventional engine-based micro-CHP systems in sales in 2012.<ref>[http://www.fuelcelltoday.com/media/1889744/fct_review_2013.pdf The fuel cell industry review 2013] {{webarchive |url=https://web.archive.org/web/20160414152813/http://www.fuelcelltoday.com/media/1889744/fct_review_2013.pdf |date=April 14, 2016 }}</ref>

==Technologies==
Micro-CHP engine systems are currently based on several different technologies:<ref name="CHP Review 2015">{{Cite journal| title = Current status of fuel cell based combined heat and power systems for residential sector | journal=Journal of Power Sources | date = 28 May 2015 | doi = 10.1016/j.jpowsour.2015.05.050 | author = Ellamla H.R. | volume = 293 | pages = 312–328 | last2 = Staffell | first2 = I|last3 = Bujlo | first3 = P|last4 = Pollet | first4 = BG| last5 = Pasupathi | first5 = S|  issue = C| bibcode=2015JPS...293..312E | hdl = 10566/6642 | hdl-access = free }}</ref>
* [[Internal combustion engine]]s
* [[Stirling engine]]s
* [[Fuel cell]]
* [[Microturbine]]s
* [[Steam engine]]/[[Steam motor]]<ref>{{Cite journal|last1=Du|first1=R.|last2=Robertson|first2=P.|date=2017|title=Cost Effective Grid-Connected Inverter for a Micro Combined Heat and Power System|journal=IEEE Transactions on Industrial Electronics|volume=64|issue=7|pages=5360–5367|doi=10.1109/TIE.2017.2677340|s2cid=1042325|issn=0278-0046|url=https://www.repository.cam.ac.uk/bitstream/1810/263361/1/Cost%20effective%20grid%20connected%20inverter%20for%20microCHP%20system.pdf}}</ref> (using either the traditional water or [[Organic Rankine cycle|organic chemicals such as refrigerants]])

===Fuels===
There are many types of fuels and sources of heat that may be considered for micro-CHP. The properties of these sources vary in terms of system cost, heat cost, environmental effects, convenience, ease of transportation and storage, system maintenance, and system life. Some of the heat sources and fuels that are being considered for use with micro-CHP include: [[natural gas]], [[Liquefied petroleum gas|LPG]], [[biomass]], vegetable oil (such as [[rapeseed]] oil), [[woodgas]], [[solar power|solar thermal]],  and lately also [[hydrogen]], as well as multi-fuel systems. The energy sources with the lowest emissions of particulates and net-carbon dioxide include solar power, hydrogen, biomass (with two-stage gasification into [[biogas]]), and natural gas. Due to the high efficiency of the CHP process, cogeneration has still lower carbon emissions compared to energy transformation in fossil driven boilers or thermal power plants.<ref>{{Cite journal|last1=Dorer|first1=Viktor|last2=Weber|first2=Andreas|date=2009-03-01|title=Energy and carbon emission footprint of micro-CHP systems in residential buildings of different energy demand levels|journal=Journal of Building Performance Simulation|volume=2|issue=1|pages=31–46|doi=10.1080/19401490802596435|s2cid=109576810|issn=1940-1493}}</ref><ref>{{Cite journal|last1=Dorer|first1=Viktor|last2=Weber|first2=Andreas|date=2009-03-01|title=Energy and CO2 emissions performance assessment of residential micro-cogeneration systems with dynamic whole-building simulation programs|journal=Energy Conversion and Management|volume=50|issue=3|pages=648–657|doi=10.1016/j.enconman.2008.10.012}}</ref>

The majority of cogeneration systems use natural gas for fuel, because natural gas burns easily and cleanly, it can be inexpensive, it is available in most areas and is easily transported through pipelines which already exist for over 60 million homes.<ref>{{Cite web|url=https://www.eia.gov/dnav/ng/ng_cons_num_dcu_nus_a.htm|title=U.S. Number of Natural Gas Consumers|website=www.eia.gov|access-date=2017-08-11}}</ref>

===Engine types===
[[Internal combustion engine|Reciprocating internal combustion engines]] are the most popular type of engine used in micro-CHP systems.<ref name=":1" /> Reciprocating internal combustion engine based systems can be sized such that the engine operates at a single fixed speed, usually resulting in a higher electrical or total efficiency. However, since [[Internal combustion engine|reciprocating internal combustion engines]] have the ability to modulate their power output by changing their operating speed and fuel input, micro-CHP systems based on these engines can have varying electrical and thermal output designed to meet changing demand.<ref>{{Cite web|url=http://www.marathonengine.com/cogeneration.html|title=ecopower® Cogeneration by Marathon Engine Systems|website=www.marathonengine.com|access-date=2017-08-11}}</ref>

Natural gas is suitable for [[internal combustion engine]]s, such as [[Otto engine]] and [[gas turbine]] systems. Gas turbines are used in many small systems due to their high efficiency, small size, clean combustion, durability and low maintenance requirements. Gas turbines designed with [[foil bearing]]s and air-cooling operate without lubricating oil or coolants. The waste heat of gas turbines is mostly in the exhaust, whereas the waste heat of [[reciprocating engine|reciprocating internal combustion engine]]s is split between the exhaust and cooling system.

[[External combustion engines]] can run on any high-temperature heat source. These engines include the [[Stirling engine]], hot "gas" turbocharger, and the [[steam engine]]. Both range from 10%-20% efficiency, and as of 2014, small quantities are in production for micro-CHP products.

Other possibilities include the [[Organic Rankine cycle]], which operates at lower temperatures and pressures using low-grade heat sources. The primary advantage to this is that the equipment is essentially an air-conditioning or refrigeration unit operating as an engine, whereby the piping and other components need not be designed for extreme temperatures and pressures, reducing cost and complexity. Electrical efficiency suffers, but it is presumed that such a system would be utilizing waste heat or a heat source such as a wood stove or gas boiler that would exist anyway for purposes of space heating.

The future of combined heat and power, particularly for homes and small businesses, will continue to be affected by the price of fuel, including natural gas. As fuel prices continue to climb, this will make the economics more favorable for energy conservation measures, and more [[efficient energy use]], including CHP and micro-CHP.

===Fuel cells===
Fuel cells generate electricity and heat as a by product. The advantages for a [[stationary fuel cell applications|stationary fuel cell application]] over stirling CHP are no moving parts, less maintenance, and quieter operation. The surplus electricity can be delivered back to the grid.<ref>[http://www.orbit.dtu.dk/files/10492422/FCCHP_LV.pdf Integration of fuel cell micro-CHPs on low voltage grid: A Danish case study] {{webarchive |url=https://web.archive.org/web/20160304072420/http://www.orbit.dtu.dk/files/10492422/FCCHP_LV.pdf |date=March 4, 2016 }}</ref>

PEMFC fuel cells fueled by natural gas or propane use a [[Steam reforming#Reforming for fuel cells|steam reformer]] to convert methane in the gas supply into [[Carbon dioxide in Earth's atmosphere|carbon dioxide]] and hydrogen; the hydrogen then reacts with oxygen in the fuel cell to produce electricity.<ref>{{cite web|url=http://www.osakagas.co.jp/en/rd/fuelcell/pefc/reformed/enefarm.html |title=Osaka Gas' fuel processing system for ENE・FARM &#124; residential polymer electrolyte fuel cell (PEFC) cogeneration system &#124; OSAKA GAS |access-date=2015-08-14 |url-status=live |archive-url=https://web.archive.org/web/20160116114226/http://www.osakagas.co.jp/en/rd/fuelcell/pefc/reformed/enefarm.html |archive-date=2016-01-16 }}</ref> A [[PEMFC]] [[fuel cell]] based micro-CHP has an electrical efficiency of 37% [[Lower heating value|LHV]] and 33% [[Higher heating value|HHV]] and a [[heat recovery]] efficiency of 52% LHV and 47%  HHV with a [[service life]] of 40,000 hours or 4000 start/stop cycles which is equal to 10 year use. An estimated 138,000 Fuel cell CHP systems below 1&nbsp;kW had been installed in Japan by the end of 2014.<ref name="CHP Review 2015"/> Most of these CHP systems are PEMFC based (85%) and the remaining are SOFC systems.

In 2013 [[Service life|Lifetime]] is 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.<ref name="fuelcelltoday.com">[http://www.fuelcelltoday.com/analysis/analyst-views/2013/13-02-27-latest-developments-in-the-ene-farm-scheme Latest developments in the Ene-Farm scheme] {{webarchive |url=https://web.archive.org/web/20160414152815/http://www.fuelcelltoday.com/analysis/analyst-views/2013/13-02-27-latest-developments-in-the-ene-farm-scheme |date=April 14, 2016 }}</ref>

[[United States Department of Energy|United States Department of Energy (DOE)]] Technical Targets: 1–10&nbsp;kW residential combined heat and power fuel cells operating on [[natural gas]].<ref>[http://energy.gov/eere/fuelcells/distributedstationary-fuel-cell-systems DOE Distributed/Stationary fuel cell systems] {{webarchive |url=https://web.archive.org/web/20141106063857/http://energy.gov/eere/fuelcells/distributedstationary-fuel-cell-systems |date=November 6, 2014 }}</ref>
{|class="wikitable"
|+Development of fuel cells
|-
!Type !! 2008!! 2012!! 2015!! 2020
|-
|Electrical efficiency at rated power<sup>2</sup>  ||34%||40%||42.5%||45%
|-
|CHP energy efficiency<sup>3</sup>   ||80%||85%||87.5%||90%
|-
|Factory cost<sup>4</sup>   ||$750/kW||$650/kW||$550/kW ||$450/kW
|-
|Transient response (10%–90% rated power) ||5 min ||4 min ||3 min ||2 min
|-
|Start-up time from 20&nbsp;°C ambient temperature||60 min ||45 min ||30 min ||20 min
|-
|Degradation with cycling<sup>5</sup>||< 2%/1000 h ||0.7%/1000 h||0.5%/1000 h ||0.3%/1000 h
|-
|Operating lifetime<sup>6</sup>||6,000 h ||30,000 h||40,000 h||60,000 h
|-
|System availability||97%||97.5%||98%||99%
|}
<sup>1</sup> Standard utility natural gas delivered at typical residential distribution line pressures.<br>
<sup>2</sup> Regulated AC net/lower heating value of fuel.<br>
<sup>3</sup> Only heat available at 80&nbsp;°C or higher is included in CHP [[Thermal efficiency|energy efficiency]] calculation.<br>
<sup>4</sup> Cost includes materials and labor costs to produce stack, plus any balance of plant necessary for stack operation. Cost defined at 50,000 unit/year production (250 MW in 5&nbsp;kW modules).<br>
<sup>5</sup> Based on operating cycle to be released in 2010.<br>
<sup>6</sup> Time until >20% net power degradation.

===Thermoelectrics===

[[Thermoelectric]] generators operating on the [[Seebeck Effect]] show promise due to their total absence of moving parts. Efficiency, however, is the major concern as most thermoelectric devices fail to achieve 5% efficiency even with high temperature differences.

=== Solar micro-CHP===

====CPVT====
This can be achieved by [[photovoltaic thermal hybrid solar collector]], another option is '''Concentrated photovoltaics and thermal''' ('''CPVT'''), also sometimes called '''combined heat and power solar''' ('''CHAPS'''), is a [[cogeneration]] technology used in concentrated photovoltaics that produce both electricity and heat in the same module. The heat may be employed in [[district heating]], [[water heating]] and [[solar cooling|air conditioning]], [[desalination]] or [[process heat]].

CPVT systems are currently in production in Europe,<ref>[http://www.renewableenergyworld.com/rea/news/article/2008/11/researchers-explore-hybrid-concentrated-solar-energy-system-53981 Renewable Energy World-Researchers explore hybrid concentrated solar energy system] {{webarchive |url=https://web.archive.org/web/20141220090012/http://www.renewableenergyworld.com/rea/news/article/2008/11/researchers-explore-hybrid-concentrated-solar-energy-system-53981 |date=December 20, 2014 }}</ref> with [[Zenith Solar]] developing CPVT systems with a claimed efficiency of 72%.<ref>{{cite web |url=http://www.zenithsolar.com/content.aspx?id=290 |title=Zenith Solar Projects – Yavne |work=zenithsolar.com |year=2011 |access-date=May 14, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110415024732/http://www.zenithsolar.com/content.aspx?id=290 |archive-date=April 15, 2011 }}</ref>

[[Sopogy]] produces a micro [[concentrated solar power]] (microCSP) system based on [[parabolic trough]] which can be installed above building or homes, the heat can be used for water heating or [[solar air conditioning]], a [[steam turbine]] can also be installed to produce electricity.

====CHP+PV====
The recent development of small scale CHP systems has provided the opportunity for in-house power backup of residential-scale [[photovoltaic]] (PV) arrays.<ref name="autogenerated1947">{{cite journal|author=J. M. Pearce|title=Expanding Photovoltaic Penetration with Residential Distributed Generation from Hybrid Solar Photovoltaic + Combined Heat and Power Systems|journal=Energy|volume=34|issue=11|pages=1947–1954|doi=10.1016/j.energy.2009.08.012|hdl=1974/5307|year=2009|bibcode=2009Ene....34.1947P |citeseerx=10.1.1.593.8182|s2cid=109780285 }} {{Open access}}</ref> The results of a recent study show that a PV+CHP hybrid system not only has the potential to radically reduce energy waste in the status quo electrical and heating systems, but it also enables the share of solar PV to be expanded by about a factor of five.<ref name="autogenerated1947"/> In some regions, in order to reduce waste from excess heat, an [[absorption chiller]] has been proposed to utilize the CHP-produced thermal energy for cooling of PV-CHP system.<ref>{{cite journal|author1=A. Nosrat|author2=J. M. Pearce|title=Dispatch Strategy and Model for Hybrid Photovoltaic and Combined Heating, Cooling, and Power Systems|journal=Applied Energy|volume=88|issue=9|year=2011|pages=3270–3276|doi=10.1016/j.apenergy.2011.02.044|hdl=1974/6439|citeseerx=10.1.1.593.5625|s2cid=110724813 }} {{Open access}}</ref> These [[Trigeneration|trigen]]+PV systems have the potential to save even more energy.

== Net metering ==
To date, micro-CHP systems achieve much of their savings, and thus attractiveness to consumers, by the value of electrical energy which is replaced by the autoproduced electricity. A "generate-and-resell" or [[net metering]] model supports this, as home-generated power exceeding the instantaneous in-home needs is sold back to the electrical utility. This system is efficient because the energy used is distributed and used instantaneously over the [[electrical grid]]. The main losses are in the transmission from the source to the consumer, which will typically be less than the losses incurred by storing energy locally or generating power at less than the peak efficiency of the micro-CHP system. So, from a purely technical standpoint [[Dynamic demand (electric power)|dynamic demand management]] and net-metering are very efficient.

Another advantage of net-metering is that it is fairly easy to configure. The user's [[electrical meter]] can easily record electrical energy exiting as well as entering the home or business. For a grid with relatively few micro-CHP users, no design changes to the electrical grid need be made. Additionally, in the United States, federal and now many state regulations require utility operators to compensate anyone adding power to the grid. From the standpoint of the grid operator, these points present operational and technical as well as administrative burdens. As a consequence, most grid operators compensate non-[[utility]] power-contributors at less than or equal to the rate they charge their customers. While this compensation scheme may seem almost fair at first glance, it only represents the consumer's cost-savings of not purchasing utility power versus the true cost of generation and operation to the micro-CHP operator. Thus from the standpoint of micro-CHP operators, net-metering is not ideal.

While net-metering is a very efficient mechanism for using excess energy generated by a micro-CHP system, it does have disadvantages: while the main generating source on the electrical grid is a large commercial generator, net-metering generators "spill" power to the [[smart grid]] in a haphazard and unpredictable fashion. However, the effect is negligible if there are only a small percentage of customers generating electricity and each of them generates a relatively small amount of electricity. When turning on an oven or space heater, about the same amount of electricity is drawn from the grid as a home generator puts out. If the percentage of homes with generating systems becomes large, then the effect on the grid may become significant. Coordination among the generating systems in homes and the rest of the grid may be necessary for reliable operation and to prevent damage to the grid.

==Market status==

===Japan===
The largest deployment of micro-CHP is in [[Japan]] in 2009 with over 90,000 units in place,<ref name="CHP Review 2015"/> with the vast majority being of [[Honda]]'s<ref>{{cite web |url=http://world.honda.com/news/2007/c070717Compact-Household-Cogeneration-Unit/ |title=Honda Worldwide &#124; July 17, 2007 "Honda's Compact Household Cogeneration Unit Achieves Cumulative Sales of 50,000 units in Japan" |publisher=World.honda.com |access-date=2012-06-12 |url-status=dead |archive-url=https://web.archive.org/web/20120615025748/http://world.honda.com/news/2007/c070717Compact-Household-Cogeneration-Unit/ |archive-date=June 15, 2012 }}</ref> "ECO-WILL" type.<ref>[https://web.archive.org/web/20141106223104/http://www.kgu.or.kr/download.php?tb=bbs_017&fn=wgcFinal00305.pdf&rn=wgcFinal00305.pdf Micro CHP in Japan]</ref>  Six Japanese energy companies launched the 300&nbsp;W–1&nbsp;kW [[PEMFC]]/[[SOFC]] ENE FARM<ref>{{in lang|en}} [http://www.jemmytex.com.tw/d_pdf/3-Tokyo%20Gas-Performance%20of%20residential%20Stationary%20PEM%20FC%20in%20actual%20and%20daily%20use%20for%20years.pdf Japan 2005-2008 mchp] {{dead link|date=June 2016|bot=medic}}{{cbignore|bot=medic}}</ref><ref>[http://www.ballard.com/files/pdf/Spec_Sheets/FCgen-1030V3_docmetrics.pdf FCgen-1030V3] {{webarchive |url=https://web.archive.org/web/20110707205926/http://www.ballard.com/files/pdf/Spec_Sheets/FCgen-1030V3_docmetrics.pdf |date=July 7, 2011 }}</ref> product in 2009, with 3,000 installed units in 2008, a production target of 150,000 units for 2009–2010 and a target of 2,500,000 units in 2030.<ref>[http://www.tokyo-gas.co.jp/tgminutes/64.pdf ENE FARM residential fuel cells launched] {{webarchive |url=https://web.archive.org/web/20120616191156/http://www.tokyo-gas.co.jp/tgminutes/64.pdf |date=June 16, 2012 }}</ref> 20,000 units were sold in 2012 overall within the Ene Farm project making an estimated total of 50,000 PEMFC and up to 5,000 SOFC installations.<ref>[http://www.iea.org/publications/insights/insightpublications/IEAJapanScorecardMASTERFINALdraft_060913_AF.pdf The IEA CHP and DHC Collaborative] {{webarchive |url=https://web.archive.org/web/20160303210659/http://www.iea.org/publications/insights/insightpublications/IEAJapanScorecardMASTERFINALdraft_060913_AF.pdf |date=March 3, 2016 }}</ref> For 2013 a state subsidy for 50,000 units is in place.<ref name="fuelcelltoday.com"/> The ENE FARM project will pass 100.000 systems in 2014, 34.213 PEMFC and 2.224 SOFC were installed in the period 2012–2014, 30,000 units on [[LNG]] and 6,000 on [[Liquefied petroleum gas|LPG]].<ref name=CalluxEn1/>

====ECOWILL====
Sold by various gas companies and as of 2013, installed in a total of 131,000 homes. Manufactured by Honda using their single cylinder EXlink engine capable of burning natural gas or propane. Each unit produces 1&nbsp;kW of electricity and 2.8&nbsp;kW of hot water.<ref>{{cite web|url=http://world.honda.com/power/cogenerator/ |title=Honda Global &#124; Honda Motor Co., Ltd. |access-date=2015-03-29 |url-status=live |archive-url=https://web.archive.org/web/20161121004839/http://world.honda.com/power/cogenerator/ |archive-date=2016-11-21 }}</ref>

====PEMFC====
*Per December 2012, [[Panasonic]] and Tokyo Gas Co., Ltd. sold about 21,000 PEM Ene-Farm units in Japan for a price of $22,600 before installation.<ref>[http://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] {{webarchive |url=https://web.archive.org/web/20140710072943/http://panasonic.co.jp/corp/news/official.data/data.dir/2013/01/en130117-5/en130117-5.html |date=July 10, 2014 }}</ref><ref>[http://panasonic.co.jp/ap/FC/en_doc03_02.html Features of the Panasonic household fuel cell] {{webarchive |url=https://web.archive.org/web/20160329121149/http://panasonic.co.jp/ap/FC/en_doc03_02.html |date=March 29, 2016 }}</ref> 
*Toshiba and Osaka Gas Co., Ltd./Nichigas<ref>[http://www.nichigas.co.jp/en/appliances/enefarm.html Nichigas Ene Farm] {{webarchive |url=https://web.archive.org/web/20131109051303/http://www.nichigas.co.jp/en/appliances/enefarm.html |date=November 9, 2013 }}</ref> installed 6,500 PEM ENE FARM units (manufactured by CHOFU SEISAKUSHO Co., Ltd.<ref>[http://techon.nikkeibp.co.jp/english/NEWS_EN/20111223/202951/?ST=english_PRINT Toshiba revamps 'Ene Farm' residential fuel cell] {{webarchive |url=https://web.archive.org/web/20160303231211/http://techon.nikkeibp.co.jp/english/NEWS_EN/20111223/202951/?ST=english_PRINT |date=March 3, 2016 }}</ref> ) per November 2011.<ref>[http://techon.nikkeibp.co.jp/english/NEWS_EN/20111223/202951/ Toshiba revamps 'Ene Farm' residential fuel cell] {{webarchive |url=https://web.archive.org/web/20160303204903/http://techon.nikkeibp.co.jp/english/NEWS_EN/20111223/202951/ |date=March 3, 2016 }}</ref>

====SOFC====
*In the middle of 2012, [[Nippon Oil|JX Nippon Oil Co.]] & [[Sanyo]] and Seibu Gas Energy Co. sold around 4,000 SOFC Ene Farm units.<ref>{{usurped|1=[https://web.archive.org/web/20160305005252/http://www.fcdic.com/eng/news/201208.pdf The latest news number 196, 2012 FCDIC ]}}</ref>
*[[Aisin Seiki]] in combination with Osaka Gas, [[Kyocera]], Toyota and Chofu Seisakusho started in April 2012 with the sales of the SOFC ENE-FARM Type S for around $33,500 before installation.<ref>[http://www.robaid.com/tech/ene-farm-type-s-most-efficient-residential-use-solid-oxide-fuel-cell.htm ENE-FARM Type S] {{webarchive |url=https://web.archive.org/web/20160317004725/http://www.robaid.com/tech/ene-farm-type-s-most-efficient-residential-use-solid-oxide-fuel-cell.htm |date=March 17, 2016 }}</ref>
*[[NGK]] is a manufacturer of 700W-1&nbsp;kW mCHP units.<ref>[http://www.fuelcellseminar.com/media/5101/hrd34-3_nishijima.pdf Development of SOFC for residential use]{{dead link|date=November 2016 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
*[[Miura Kogyo]]<ref>[http://www.miuraz.co.jp/en/ Miura] {{webarchive |url=https://web.archive.org/web/20160504231215/http://www.miuraz.co.jp/en/ |date=May 4, 2016 }}</ref> and [[Sumitomo Precision Products]] with a 4.2&nbsp;kW unit.
*[[Toto Ltd.]]<ref>[http://www.fuelcellseminar.com/media/9333/a399_1.pdf Toto Ltd]{{dead link|date=November 2016 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

===South Korea===
In [[South Korea]], subsidies will start at 80 percent of the cost of a domestic fuel cell.<ref>[http://www.businessgreen.com/business-green/news/2248391/south-korea-unveils-80-per-cent South Korea unveils 80 per cent subsidy for domestic fuel cells] {{webarchive |url=https://web.archive.org/web/20100317123157/http://www.businessgreen.com/business-green/news/2248391/south-korea-unveils-80-per-cent |date=March 17, 2010 }}</ref> The [[Renewable portfolio standard|Renewable Portfolio Standard]] program with [[Renewable Energy Certificate (United States)|renewable energy certificate]]s runs from 2012 to 2022.<ref>[http://www.fuelcellseminar.com/media/5505/kim_10_19_2010.pdf R&D status and prospects on fuel cells in Korea] {{webarchive |url=https://web.archive.org/web/20131205044729/http://www.fuelcellseminar.com/media/5505/kim_10_19_2010.pdf |date=December 5, 2013 }}</ref> 
Quota systems favor large, vertically integrated generators and multinational electric utilities, if only because certificates are generally denominated in units of one megawatt-hour. They are also more difficult to design and implement than a [[Feed-in tariff]].<ref name="wind-works.org">[http://www.wind-works.org/FeedLaws/RenewableEnergyPolicyMechanismsbyPaulGipe.pdf Renewable Energy Policy Mechanisms by Paul Gipe] {{webarchive |url=https://web.archive.org/web/20120510072741/http://www.wind-works.org/FeedLaws/RenewableEnergyPolicyMechanismsbyPaulGipe.pdf |date=May 10, 2012 }}(1.3MB)<br/>Lauber, V. (2004). "REFIT and RPS: Options for a harmonized Community framework," Energy Policy, Vol. 32, Issue 12, pp.1405–1414.<br/>Lauber, V. (2008). "Certificate Trading – Part of the Solution or Part of the Problem?"
Ljubljana Conference on the Future of GHG Emissions Trading in the EU, March 2008. Salzburg, Austria: University of Salzburg. Retrieved 16 March 2009 at: www.uni-salzburg.at/politikwissenschaft/lauber
</ref> Around 350 residential mCHP units were installed in 2012.<ref>[http://www.fuelcelltoday.com/media/1713685/fct_review_2012.pdf The fuel cell industry review 2012] {{webarchive |url=https://web.archive.org/web/20160701231144/http://www.fuelcelltoday.com/media/1713685/fct_review_2012.pdf |date=July 1, 2016 }}</ref>

*PEMFC by [[GS Group|GS FuelCell]],<ref>[http://gsfc.en.ec21.com/Small_Stationary_Fuel_Cell_System--5432929.html GS Fuelcell Co., Ltd] {{webarchive |url=https://web.archive.org/web/20160303220146/http://gsfc.en.ec21.com/Small_Stationary_Fuel_Cell_System--5432929.html |date=March 3, 2016 }}</ref> FuelCell Power,<ref>[http://www.fuelcellpower.co.kr/eng/index.php FuelCell Power] {{webarchive |url=https://web.archive.org/web/20140707060623/http://www.fuelcellpower.co.kr/eng/index.php |date=July 7, 2014 }}</ref> [[Hyundai Hysco]]<ref>[https://www.hysco.com/eng/product/fuel_cell01.aspx Hyundai Hysco] {{webarchive |url=https://web.archive.org/web/20150131225251/https://www.hysco.com/eng/product/fuel_cell01.aspx |date=January 31, 2015 }}</ref> [[Joint venture|JV]] with [[Plug Power]] and [[Hyosung]],<ref>[http://www.hyosungpni.com/eng/product/GreenEnergy/FuelCellSystem/RND1kWLowTemperaturePEMFCSystem.jsp Hyosung’s 1kW low temperature PEMFC System] {{webarchive |url=https://web.archive.org/web/20160304040845/http://www.hyosungpni.com/eng/product/GreenEnergy/FuelCellSystem/RND1kWLowTemperaturePEMFCSystem.jsp |date=March 4, 2016 }}</ref> 
*SOFC by [[KEPRI]],<ref>[http://www.kepri.re.kr/ Kepri] {{webarchive |url=https://web.archive.org/web/20150709014608/http://www.kepri.re.kr/ |date=July 9, 2015 }}</ref> [[LS Group|LS Industrial Systems]] (from [[ClearEdge Power]]), Samsung Everland (ClearEdge Power).
*[[Molten carbonate fuel cell|MCFC]] by [[POSCO Energy]] ([[FuelCell Energy]]) <ref>[http://www.iphe.net/docs/Events/Japan_3-11/2%20Park_KOGAS.pdf 2009-Initial stage of commercialization of residential fuel cells in Korea] {{webarchive |url=https://web.archive.org/web/20160304031401/http://www.iphe.net/docs/Events/Japan_3-11/2%20Park_KOGAS.pdf |date=March 4, 2016 }}</ref> and [[Doosan Heavy Industries & Construction|Doosan]].
*PAFC [[Doosan Fuel Cell America]]
*AFC [[AFC Energy]]

===Europe===
The European [[public–private partnership]] [[Fuel Cells and Hydrogen Joint Technology Initiative|Fuel Cells and Hydrogen Joint Undertaking]] [[Framework Programmes for Research and Technological Development|Seventh Framework Programme]] project ene.field aims to deploy by 2017<ref>[http://www.fch-ju.eu/sites/default/files/documents/sga2012/Presentation%20Fiona%20Riddoch-%20Session%20II.pdf 5th stakeholders general assembly of the FCH JU] {{webarchive |url=https://web.archive.org/web/20131110030750/http://www.fch-ju.eu/sites/default/files/documents/sga2012/Presentation%20Fiona%20Riddoch-%20Session%20II.pdf |date=November 10, 2013 }}</ref> up 1,000 residential fuel cell Combined Heat and Power (micro-CHP) installations in 12 EU member states. 
*The programme brings together 9 mature European micro FC-CHP manufacturers into a common analysis framework to deliver trials across all of the available fuel cell CHP technologies. Fuel cell micro-CHP trials will be installed and actively monitored in dwellings across the range of European domestic heating markets, dwelling types and [[climatic zone]]s, which will lead to an invaluable dataset on domestic energy consumption and micro-CHP applicability across Europe.
*The ene.field project also brings together over 30 utilities, housing providers and municipalities to bring the products to market and explore different business models for micro-CHP deployment.<ref>[http://enefield.eu/ ene.field] {{webarchive |url=https://web.archive.org/web/20161002024915/http://enefield.eu/ |date=October 2, 2016 }}</ref><ref>[http://www.h2fc-fair.com/hm13/images/ppt/10we/1420-1.pdf European-wide field trials for residential fuel cell micro-CHP] {{webarchive |url=https://web.archive.org/web/20161109221035/http://www.h2fc-fair.com/hm13/images/ppt/10we/1420-1.pdf |date=November 9, 2016 }}</ref><ref>[http://enefield.eu/wp-content/uploads/2013/04/Progress-Report-1-M1-M6-Final.pdf ene.field Grant No 303462] {{webarchive |url=https://web.archive.org/web/20131110070103/http://enefield.eu/wp-content/uploads/2013/04/Progress-Report-1-M1-M6-Final.pdf |date=November 10, 2013 }}</ref>

===Sweden===
[[Powercell Sweden]] is a fuel cell company that develop environmentally friendly electric generators with the unique fuel cell and reformer technology that is suitable for both existing and future fuel.

===Germany===
In Germany, ca 50 MW of mCHP up to 50&nbsp;kW units have been installed in 2015.<ref>[http://www.bafa.de/bafa/de/energie/kraft_waerme_kopplung/publikationen/statistik_kwkanlagen.xlsx BAFA: Official statistics on CHP units commissioned per year, downloaded 2016-03-12]{{dead link|date=November 2016 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> The German government is offering large CHP incentives, including a [[market premium]] on electricity generated by CHP and an investment bonus for micro-CHP units. The German testing project Callux has 500 mCHP installations per nov 2014.<ref name="CalluxEn1">[http://www.hyer.eu/2014/enfarm-enefield-eneware Enfarm enefield eneware] {{webarchive |url=https://web.archive.org/web/20160215204028/http://www.hyer.eu/2014/enfarm-enefield-eneware |date=February 15, 2016 }}</ref> [[North Rhine-Westphalia]] launched a 250 million subsidy program for up to 50&nbsp;kW lasting until 2017.<ref>[http://www.hyer.eu/members/germany/nordrhein-westfalen/nordrhein-westfalen-news/north-rhine-westphalia-government-to-subsidise-fuel-cell-m-chp North Rhine-Westphalia government launches capital subsidy for micro-CHP] {{webarchive |url=https://web.archive.org/web/20131109085658/http://www.hyer.eu/members/germany/nordrhein-westfalen/nordrhein-westfalen-news/north-rhine-westphalia-government-to-subsidise-fuel-cell-m-chp |date=November 9, 2013 }}</ref>

====PEMFC====
*[[BDR Thermea]]/[[Baxi|BAXI]] (Toshiba)
*[[Viessmann]] (Panasonic)<ref>{{usurped|1=[https://web.archive.org/web/20141006164002/http://www.fcdic.com/eng/news/201311.pdf Number 211-2013 FDIC -Viesmann-Panasonic]}}</ref>
*[[Elcore]],<ref>[http://arquivo.pt/wayback/20160517023333/http://www.elcomax.com/ Elcore – Elcomax ]</ref> a 300W addon.<ref>[http://www.fuelcelltoday.com/analysis/analyst-views/2013/13-08-14-handling-the-cost-of-residential-fuel-cells Handling the cost of residential fuel cells] {{webarchive |url=https://web.archive.org/web/20160406165718/http://www.fuelcelltoday.com/analysis/analyst-views/2013/13-08-14-handling-the-cost-of-residential-fuel-cells |date=April 6, 2016 }}</ref>
*[[Tropical (vehicles)|Tropical]]<ref>[http://www.tropical.gr/products/fuel-cell-power-generators/1kw-hydrogen-fc-power-generator.html Tropical] {{webarchive |url=https://web.archive.org/web/20160404164257/http://www.tropical.gr/products/fuel-cell-power-generators/1kw-hydrogen-fc-power-generator.html |date=April 4, 2016 }}</ref>
*[[Dantherm|Dantherm Power]]
*[[Riesaer Brennstoffzellentechnik GmbH]] (Inhouse Engineering)<ref>[https://web.archive.org/web/20150402153015/http://www.inhouse-engineering.com/en/fuel-cell-systems/products/pem-fuel-cell-stack-from-1-to-5-kw-electrical-power/ Inhouse]</ref>

====SOFC====
*[[Center for Fuel Cell Technology]] (ZBT) ([[Nippon Oil|JX Nippon]])<ref>[http://www.zbt-duisburg.de/en/meta-menu/news-anzeige-eng/article/deutsch-japanisches-kooperationsprojekt/ ZBT] {{webarchive |url=https://web.archive.org/web/20160327182210/http://www.zbt-duisburg.de/en/meta-menu/news-anzeige-eng/article/deutsch-japanisches-kooperationsprojekt/ |date=March 27, 2016 }}</ref> 
*[[Ceramic Fuel Cells]] installs until 2014 up to 100 SOFC units under the SOFT-PACT<ref>[http://www.fch-ju.eu/project/solid-oxide-fuel-cell-micro-chp-field-trials Solid oxide fuel cell micro-CHP field trials] {{webarchive |url=https://web.archive.org/web/20141006093820/http://www.fch-ju.eu/project/solid-oxide-fuel-cell-micro-chp-field-trials |date=October 6, 2014 }}</ref> project with E.ON in Germany and the UK. A factory in [[Heinsberg]], Germany for the production of SOFC based micro-CHP units started in June 2009 to produce 10,000 two-kilowatt units per year.<ref>[http://peakenergy.blogspot.com/2008/03/cogeneration-at-home-ceramic-fuel-cells.html Ceramic fuel cells] {{webarchive |url=https://web.archive.org/web/20160629205741/http://peakenergy.blogspot.com/2008/03/cogeneration-at-home-ceramic-fuel-cells.html |date=June 29, 2016 }}</ref> 
*[[Vaillant Group|Vaillant]] (Sunfire/Staxera)<ref>[http://www.sunfire.de/en Sunfire] {{webarchive |url=https://web.archive.org/web/20161128121152/http://www.sunfire.de/en |date=November 28, 2016 }}</ref>
*Buderus/Junkers  – [[Bosch Thermotechnik]] (Aisin Seiki)<ref>[http://enefield.eu/field-trials/installations/first-buderus-ene-field-fuel-cell-system-successfully-tested-in-single-family-home/  Buderus Logapower FC10 energy centre supplies both heat and electricity] {{webarchive |url=https://web.archive.org/web/20150209082113/http://enefield.eu/field-trials/installations/first-buderus-ene-field-fuel-cell-system-successfully-tested-in-single-family-home/ |date=February 9, 2015 }}</ref>
*[[SOFCpower]]/[[Ariston (company)|Ariston]]
*Itho-Daalderop ([[Ceres Power]])
*[[Viessmann]] ([[HEXIS]]),<ref>[http://www.hexis.com/ Hexis] {{webarchive |url=https://web.archive.org/web/20160520130020/http://www.hexis.com/ |date=May 20, 2016 }}</ref><ref>[http://alpha.arabianindustry.com/markets/reviews/2012/nov/21/viessmann-joins-forces-to-power-fuel-cell-industry-3470701/#.VIyCocnAqT0 Viessmann has announced two separate deals with Hexis] {{webarchive |url=https://web.archive.org/web/20160318205639/http://alpha.arabianindustry.com/markets/reviews/2012/nov/21/viessmann-joins-forces-to-power-fuel-cell-industry-3470701/#.VIyCocnAqT0 |date=March 18, 2016 }}</ref>

===UK===
It is estimated that about 1,000 micro-CHP systems were in operation in the UK as of 2002. These are primarily [[Applications of the Stirling engine#MicroCHP|Whispergen]] using [[Stirling engine]]s, and Senertec Dachs [[reciprocating engine]]s. The market is supported by the government through regulatory work, and some government research money expended through the Energy Saving Trust and [[The Carbon Trust|Carbon Trust]], which are public bodies supporting energy efficiency in the UK.<ref>[http://www.chpa.co.uk/events/2006/national_conference/presentations/1400%20Ian%20Stares.pdf CHP–The microgeneration boom?] {{webarchive |url=https://web.archive.org/web/20090106122855/http://www.chpa.co.uk/events/2006/national_conference/presentations/1400%20Ian%20Stares.pdf |date=January 6, 2009 }}</ref> Effective as of 7 April 2005, the UK government cut the VAT from 17.5% to 5% for micro-CHP systems, in order to support demand for this emerging technology at the expense of existing, less environmentally friendly technology. Of the 24 million households in the UK, as many as 14 to 18 million are thought to be suitable for micro-CHP units.<ref>[http://www.ecuity.com/wp-content/uploads/2013/03/The-role-of-micro-CHP-in-a-smart-energy-world.pdf The role of micro CHP in a smart energy world = March 2013] {{webarchive |url=https://web.archive.org/web/20160304072549/http://www.ecuity.com/wp-content/uploads/2013/03/The-role-of-micro-CHP-in-a-smart-energy-world.pdf |date=March 4, 2016 }}</ref>

====PEMFC====
*In early 2012 less than 1000 1 kWe [[Baxi]]-Innotech <ref>[http://www.baxi-innotech.de/ BAXI-Innotech] {{webarchive |url=https://web.archive.org/web/20150205013111/http://www.baxi-innotech.de/ |date=February 5, 2015 }}</ref> PEM micro-CHP units from [[BDR Thermea]] were installed <ref name="cospp.com">[http://www.cospp.com/articles/print/volume-13/issue-3/features/micro-chp-japan-continues-to-lead-as-fuel-cells-units-emerge.html Micro-CHP Japan continues to lead as fuel cell units emerge] {{webarchive |url=https://web.archive.org/web/20160111154957/http://www.cospp.com/articles/print/volume-13/issue-3/features/micro-chp-japan-continues-to-lead-as-fuel-cells-units-emerge.html |date=January 11, 2016 }}</ref>
*[[Intelligent Energy|IE-CHP]]

====SOFC====
*A [[Ceres Power]] factory in [[Horsham]] UK for the production of [[SOFC]] based micro-CHP units is expected to start low-volume production in the second half of 2009<ref>.[http://www.renewableenergyfocus.com/view/4212/ceres-power-signs-fuel-cell-chp-assembly-deal-with-daalderop/ Ceres Power signs fuel cell CHP assembly deal with Daalderop] {{webarchive |url=https://web.archive.org/web/20160320201821/http://www.renewableenergyfocus.com/view/4212/ceres-power-signs-fuel-cell-chp-assembly-deal-with-daalderop/ |date=March 20, 2016 }}</ref>
*[[Ceramic Fuel Cells]]

===Denmark===
The Danish mCHP project 2007 to 2014 with 30 units is on the island of [[Lolland]] and in the western town [[Varde]].<ref>[http://www.fuelcellseminar.com/assets/pdf/2008/tuesday/DEM23-2_AHPederson.ppt.pdf Demonstration of micro CHP based on Danish fuel cells] {{webarchive |url=https://web.archive.org/web/20141106133352/http://www.fuelcellseminar.com/assets/pdf/2008/tuesday/DEM23-2_AHPederson.ppt.pdf |date=November 6, 2014 }}</ref> Denmark is currently part of the Ene.field project.
*[[EWII Fuel Cell]]
*[[Dantherm|Dantherm Power]] ([[Ballard Power]])

===The Netherlands===
The micro-CHP subsidy was ended in 2012.<ref name="cospp.com"/> To test the effects of mCHP on a [[smart grid]], 45 [[natural gas]] [[SOFC]] units (each 1,5 kWh) from Republiq Power ([[Ceramic Fuel Cells]]) will be placed on [[Ameland]] in 2013 to function as a [[virtual power plant]].<ref>{{cite web|url=http://www.waddenfonds.nl/fileadmin/waddenfonds/inhd_wadfonds/Projecten/pdf/bijl_PB_WF_29okt2013.pdf|title=Methaanbrandstoffen op Ameland|language=nl|url-status=dead|archive-url=https://web.archive.org/web/20131101212845/http://www.waddenfonds.nl/fileadmin/waddenfonds/inhd_wadfonds/Projecten/pdf/bijl_PB_WF_29okt2013.pdf|archive-date=2013-11-01}}</ref>

===United States===
{{update section|date=July 2019}}
The  federal government is{{when|date=July 2019}} offering a 10% [[tax credit]] for smaller CHP and micro-CHP commercial applications.{{citation needed|date=July 2019}}

In 2007, the United States company "Climate Energy" of Massachusetts introduced the "Freewatt,<ref>[http://www.cdhenergy.com/presentations/Freewatt%20Report%20-%20October2011.pdf ANnalysis of data collected for the Freewatt microCHP system in Syracuse, NY] {{webarchive |url=https://web.archive.org/web/20150402133610/http://www.cdhenergy.com/presentations/Freewatt%20Report%20-%20October2011.pdf |date=April 2, 2015 }}</ref> a micro-CHP system  based on a [[Honda]] MCHP engine bundled with a gas furnace (for warm air systems) or boiler (for hydronic or forced hot water heating systems).

*AFC [[Doosan Fuel Cell America]]
*PEMFC [[Plug Power]] ([[Ballard Power Systems]])
The Freewatt is no longer commercially available (since at least 2014). Through testing it was found to operate at 23.4% efficiency for electrical and 51% efficiency for waste heat recovery.<ref name=":2">Taie, Z., Hagen, C. (2016). ARPA-e Final Scientific/Technical Report - Home Generator Benchmarking Program. Oregon State University. Bend, Oregon.</ref><ref name=":3">{{Cite journal|last1=Taie|first1=Zachary|last2=West|first2=Brian|last3=Szybist|first3=James|last4=Edwards|first4=Dean|last5=Thomas|first5=John|last6=Huff|first6=Shean|last7=Vishwanathan|first7=Gokul|last8=Hagen|first8=Christopher|date=2018-06-15|title=Detailed thermodynamic investigation of an ICE-driven, natural gas-fueled, 1 kWe micro-CHP generator|journal=Energy Conversion and Management|volume=166|pages=663–673|doi=10.1016/j.enconman.2018.04.077|osti=1436052|s2cid=102973318 |issn=0196-8904|doi-access=free|bibcode=2018ECM...166..663T |url=https://www.osti.gov/biblio/1436052}}</ref>

Marathon Engine Systems, a Wisconsin company, produces a variable electrical and thermal output micro-CHP system called the ecopower with an electrical output of 2.2-4.7 kWe. The ecopower was independently measured to operate at 24.4% and 70.1% electrical and waste heat recovery efficiency, respectively.<ref name=":2" /><ref name=":4">{{Cite journal|last1=Taie|first1=Zachary|last2=Hagen|first2=Christopher|date=2019-01-15|title=Experimental thermodynamic first and second law analysis of a variable output 1–4.5 kWe, ICE-driven, natural-gas fueled micro-CHP generator|journal=Energy Conversion and Management|volume=180|pages=292–301|doi=10.1016/j.enconman.2018.10.075|s2cid=102511621 |issn=0196-8904|doi-access=free|bibcode=2019ECM...180..292T }}</ref>

===Canada===
{{update section|date=July 2019}}
*Hyteon PEM <ref>[http://www.hyteon.com/Hyteon-Brochure.pdf Hyteon] {{webarchive |url=https://web.archive.org/web/20160303224039/http://www.hyteon.com/Hyteon-Brochure.pdf |date=March 3, 2016 }}</ref>

Through a pilot program scheduled for mid-2009 in the Canadian province of Ontario, the Freewatt system is being offered by home builder Eden Oak<ref>{{Cite web | url=http://edenoak.com/ |title = New Homes & Spectacular Communities in Southern Ontario}}</ref> with support from ECR International,<ref>{{Cite web | url=http://www.ecrinternational.com |title = ECR International &#124; A Family of Heating & Cooling Brands}}</ref> [[Enbridge]] Gas Distribution and [[Electrical grid|National Grid]].<ref>{{cite web|url=https://www.thestar.com/life/health_wellness/2008/09/20/huge_savings_claimed_by_new_system.html |title=Huge savings claimed by new system |website=[[Toronto Star]] |date=20 September 2008 |access-date=2015-03-29 |url-status=live |archive-url=https://web.archive.org/web/20150402143917/http://www.thestar.com/life/health_wellness/2008/09/20/huge_savings_claimed_by_new_system.html |archive-date=2015-04-02 }}</ref>

==Research==
Testing is underway in [[Ameland]], the Netherlands for a three-year field testing until 2010 of  [[HCNG]]  where 20% hydrogen is added to the local [[Compressed natural gas|CNG]] distribution net, the appliances involved are [[kitchen stove]]s, [[condensing boiler]]s, and micro-CHP boilers.<ref>[http://corporateuk.eneco.nl/outlook_and_strategy/innovation/Pages/ThenewHReboiler.aspx Micro-CHP] {{webarchive |url=https://web.archive.org/web/20120227103548/http://corporateuk.eneco.nl/outlook_and_strategy/innovation/Pages/ThenewHReboiler.aspx |date=February 27, 2012 }}</ref><ref>[https://archive.today/20120717053401/http://translate.google.com/translate?u=http://www.waterstofvereniging.nl/nieuws/opinie-ameland.html&sl=nl&tl=en&hl=en&ie=UTF-8 Ameland Field testing]</ref>

Micro-CHP Accelerator, a field trial performed between 2005 and 2008, studied the performance of 87 [[Stirling engine]] and [[internal combustion engine]] devices in residential houses in the UK. This study found that the devices resulted in average carbon savings of 9% for houses with heat demand over 54 GJ/year.<ref>{{cite report |author = Carbon Trust |date = 2011 |title = Micro-CHP Accelerator |url = http://www.carbontrust.com/media/77260/ctc788_micro-chp_accelerator.pdf}}</ref>

An ASME (American Society of Mechanical Engineers) paper fully describes the performance and operating
experience with two residential sized Combined Heat and Power units which were in operation from 1979
through 1995.<ref>Frederick R. Rosse: [http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1580378 EXPERIENCE WITH EARLY DISTRIBUTED GENERATION SYSTEMS] {{webarchive |url=https://web.archive.org/web/20160314013035/http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1580378 |date=March 14, 2016 }}, Proceedings of IJPC-2003 2003 International Joint Power Conference, paper IJPGC2003-40192</ref>

Oregon State University, funded by the U.S. Department of Energy's Advanced Research Project Agency - Energy (ARPA-e), tested the state of the art micro-CHP systems in the United States. The results showed that the nominally 1 kWe state-of-the-art micro-CHP system operated at an electrical and total efficiency (LHV based) of 23.4 and 74.4%, respectively.<ref name=":3" /> The nominally 5 kWe state-of-the-art system operated at an electrical and total efficiency (LHV based) of 24.4 and 94.5%, respectively.<ref name=":4" /> The most popular 7 kWe home backup generator (not CHP) operated at an electrical efficiency (LHV based) of 21.5%. The price of the emergency backup generator was an order of magnitude lower than the 5 kWe generator, but the projected life span of the system was over 2 orders of magnitude lower. These results show the trade-off between efficiency, cost, and durability.<ref name=":2" />

The U.S. Department of Energy's Advanced Research Project Agency - Energy (ARPA-e) has funded $25 million towards mCHP research in the GENerators for Small Electrical and Thermal Systems (GENSETS) program.<ref>{{Cite web|url=https://arpa-e.energy.gov/?q=arpa-e-programs/gensets|title=GENSETS|website=ARPA-e|access-date=11 August 2017}}</ref><ref>{{Cite web|url=https://arpa-e.energy.gov/?q=news-item/department-energy-announces-18-new-projects-accelerate-technologies-efficient-residential|title=DEPARTMENT OF ENERGY ANNOUNCES 18 NEW PROJECTS TO ACCELERATE TECHNOLOGIES FOR EFFICIENT RESIDENTIAL COMBINED HEAT AND POWER GENERATION AND BIOENERGY CROP DEVELOPMENT|website=ARPA-e|access-date=11 August 2017}}</ref> 12 project teams have been selected to develop a 1 kWe mCHP technology that can achieve 40% electrical efficiency, have a 10-year system life, and cost under $3000.

==See also==
{{Portal|Energy|Renewable energy}}
{{colbegin}}
*[[Distributed generation]]
*[[District heating]]
*[[Feed-in tariff]]
*[[Geothermal power in Iceland]]
*[[Grid-tied electrical system]]
*[[Home fuel cell]]
*[[Pinch analysis]]
*[[Relative cost of electricity generated by different sources]]
*[[Stationary fuel cell applications]]
*[[Timeline of hydrogen technologies]]
*[[Trigeneration]]
*[[Virtual power plant]]
{{colend}}

== References ==
{{Reflist|30em}}

==External links==
* [http://energy.gov/eere/fuelcells/distributedstationary-fuel-cell-systems DOE USA fuel cells in combined heat and power]

{{Electricity generation}}
{{Authority control}}

[[Category:Cogeneration]]
[[Category:Renewable energy]]
[[Category:Hydrogen technologies]]