Micro combined heat and power | Wikipedia audio article


Micro combined heat and power or micro-CHP
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 kW. 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
heat transfer in district 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.==Overview==
Combined heat and power (CHP) systems for homes or small commercial buildings are often
fueled by natural gas to produce electricity and heat. A micro-CHP system usually contains a small
fuel cell or a 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 heating, ventilation, and air conditioning. A micro-CHP generator may primarily follow
heat demand, delivering electricity as the by-product, or may follow electrical demand
to generate electricity and use heat as the by-product. When used primarily for heating, micro-CHP
systems may generate more electricity than is instantaneously being demanded in circumstances
of fluctuating electrical demand. The heat engine version is a small scale example
of cogeneration schemes which have been used with large electric power plants. The purpose of cogeneration is to utilize
more of the energy in the fuel. The reason for using such systems is that
heat engines, such as steam power plants which generate the electric power needed for modern
life by burning fuel, are not very efficient. Due to Carnot’s theorem, a heat engine cannot
be 100% efficient; it cannot convert anywhere near all the heat produced from the fuel it
burns into organized forms of energy such as electricity. Therefore, heat engines always produce a surplus
of low-temperature waste heat, called “secondary heat” or “low-grade heat”. Modern plants are limited to efficiencies
of about 33–63% at most, so 37–67% of the energy is exhausted as waste heat. In the past this energy was usually wasted
to the environment. Cogeneration systems, built in recent years
in cold-climate countries, utilize the waste heat produced by large power plants for heating
by piping hot water from the plant into buildings in the surrounding community. However, it is not practical to transport
heat long distances due to heat loss from the pipes. Since electricity can be transported practically,
it is more efficient to generate the electricity near where the waste heat can be used. So in a “micro-combined heat and power system”
(micro-CHP), small power plants are instead located where the secondary heat can be used,
in individual buildings. Micro-CHP is defined by the EC as being of
less than 50 kW electrical power output, however, others have more restrictive definitions,
all the way down to20% 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 air conditioning, desalination or process heat. CPVT systems are currently in production in
Europe, with Zenith Solar developing CPVT systems with a claimed efficiency of 72%.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. 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. 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. These 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 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 management and net-metering are very efficient. Another positive to net-metering is the fact
that it is fairly easy to configure. The user’s electrical meter is simply able
to record electrical power exiting as well as entering the home or business. As such, it records the net amount of power
entering the home. 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 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 detractors. Of the detractors’ main points, the first
to consider is that 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 where over 90,000 units in place, with the vast majority being of Honda’s “ECO-WILL”
type. Six Japanese energy companies launched the
300 W–1 kW PEMFC/SOFC ENE FARM 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. 20,000 units where sold in 2012 overall within
the Ene Farm project making an estimated total of 50,000 PEMFC and up to 5,000 SOFC installations. For 2013 a state subsidy for 50,000 units
is in place. 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 LPG.====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 kW of electricity and
2.8 kW of hot water.====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. Toshiba and Osaka Gas Co., Ltd./Nichigas installed
6,500 PEM ENE FARM units (manufactured by CHOFU SEISAKUSHO Co.,Ltd. ) per November 2011.====SOFC====
In the middle of 2012, JX Nippon Oil Co. & Sanyo and Seibu Gas Energy Co. sold around 4,000
SOFC Ene Farm units. 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. NGK is a manufacturer of 700W-1 Kw mCHP units. Miura Kogyo and Sumitomo Precision Products
with a 4.2 Kw unit. Toto Ltd.===South Korea===
In South Korea, subsidies will start at 80 percent of the cost of a domestic fuel cell. The Renewable Portfolio Standard program with
renewable energy certificates runs from 2012 to 2022. 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. Around 350 residential mCHP units were installed
in 2012. PEMFC by GS FuelCell, FuelCell Power, Hyundai
Hysco JV with Plug Power and Hyosung, SOFC by KEPRI, LS Industrial Systems (from
ClearEdge Power), Samsung Everland (ClearEdge Power). MCFC by POSCO Energy (FuelCell Energy) and
Doosan. PAFC Doosan Fuel Cell America
AFC AFC Energy===Europe===
The European public–private partnership Fuel Cells and Hydrogen Joint Undertaking
Seventh Framework Programme project ene.field aims to deploy by 2017 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 zones, 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.===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 kW units have been installed in 2015. 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. North Rhine-Westphalia launched a 250 million
subsidy program for up to 50 kW lasting until 2017.====PEMFC====
BDR Thermea/BAXI (Toshiba) Viessmann (Panasonic)
Elcore, a 300W addon. Tropical
Dantherm Power Riesaer Brennstoffzellentechnik GmbH (Inhouse
Engineering)====SOFC====
Center for Fuel Cell Technology (ZBT) (JX Nippon)
Ceramic Fuel Cells installs until 2014 up to 100 SOFC units under the SOFT-PACT 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. Vaillant (Sunfire/Staxera)
Buderus/Junkers – Bosch Thermotechnik (Aisin Seiki)
SOFCpower/Ariston Itho-Daalderop (Ceres Power)
Viessmann (HEXIS),===UK===
It is estimated that about 1,000 micro-CHP systems were in operation in the UK as of
2002. These are primarily Whispergen using Stirling
engines, and Senertec Dachs reciprocating engines. The market is supported by the government
through regulatory work, and some government research money expended through the Energy
Saving Trust and Carbon Trust, which are public bodies supporting energy efficiency in the
UK. Effective as of 7 April 2005, the UK government
has cut the VAT from 20% to 5% for micro-CHP systems, in order to support demand for this
emerging technology at the expense of existing, less environmentally friendly technology. The reduction in VAT is effectively a 10.63%
subsidy for micro-CHP units over conventional systems, which will help micro-CHP units become
more cost competitive, and ultimately drive micro-CHP sales in the UK. Of the 24 million households in the UK, as
many as 14 to 18 million are thought to be suitable for micro-CHP units. Two fuel cell varieties of mCHP co-generation
units are almost ready for mainstream production and are planned for release to commercial
markets in early in 2014. With the UK Government’s Feed-In-Tariff available
for a 10-year period, a wide uptake of the technology is anticipated.====PEMFC====
In early 2012 less than 1000 1 kWe Baxi-Innotech PEM micro-CHP units from BDR Thermea were
installed 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 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. Denmark is currently part of the Ene.field
project. EWII Fuel Cell
Dantherm Power (Ballard Power)===The Netherlands===
The micro-CHP subsidy was ended in 2012. 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.===United States===
The federal government is offering a 10% tax credit for smaller CHP and micro-CHP commercial
applications.In 2007, the United States company “Climate Energy” of Massachusetts introduced
the “Freewatt, 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.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.===Canada===
Hyteon PEM 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 with support from ECR International,
Enbridge Gas Distribution and National Grid.==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 CNG distribution net, the appliances
involved are kitchen stoves, condensing boilers, and micro-CHP boilers.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.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.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. 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. 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.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. 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

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