Solid oxide fuel cell micro-combined heat and power plants being developed for the home

December 4th, 2010 by Riso National Laboratory for Sustainable Energy

A solid oxide fuel cell (SOFC) produces electricity and heat with a high efficiency, which means that less carbon emissions are produced for each kilowatt generated.  The production of electricity happens with nearly no emissions of nitrogen and sulphur oxides.  SOFC have important attributes for a future climate-friendly energy supply.

A SOFC is flat and thin as a piece of paper and provide a voltage of approximately one volt.  SOFCs are put together in stacks to achieve the desired voltage and wattage.

Risø DTU entered into a long-term strategic cooperation agreement with Topsoe Fuel Cell, which develops fuel cell stacks commercially.  They are now being sold under the name Topsoe PowerCores™.

Topsoe Fuel Cell has subsequently entered into a long-term cooperation agreement with the Danish company Dantherm Power, which is selling small CHP plants.   Research conducted at Risø DTU’s laboratories is helping develop commercial products for the supply of power and heat.

A micro-combined heat and power plant developed by Dantherm A/S (click image to expand - © Dantherm A/S)

Our future electricity system will look significantly different from now.   Large, central Combined Heat and Power (CHP) plants will be probably supplemented with numerous home-installed small CHP plants of a few kilowatts.  These home micro CHP plants can help balance energy in the future energy system, where more energy will be coming from renewable energy sources such as the wind and the sun. The micro CHP plants can supply energy supply when there is no wind or sunshine.

“Topsoe Fuel Cell provides the engine, we produce the rest of what is to surround the engine in order to finally end up having a fully operational micro CHP plant,” says Jesper Themsen from Dantherm Power. The core technology at Topsoe Fuel Cell is based on fuel cells developed at Risø DTU.

“At the moment, we are developing compact micro CHP plants, similar to a conventional oil or gas furnace when it comes to generating heat for the home. What’s new about micro CHP plants, is that they also produce the power the home needs. In this way, you avoid transmission loss in the electricity and district heating network,” says Jesper Themsen, Technical Director at Dantherm Power. The micro CHP plants emit no or very little pollution and less carbon emissions.

“In the spring of 2010 we produced a few micro CHP plants as part of the project ‘Danish micro cogeneration’. Now we’re doing tomorrow’s micro CHP plant in cooperation with Topsoe Fuel Cell, and in October 2010, we produced two systems that we will put into operation by professional users such as plumbers or electricians. People with craftsman experience who can help us solve the problems that naturally arise with the plants during the first phase,” says Jesper Themsen. The first plants will generate 1 kW of power and 1 kW of heat and will be powered by natural gas.

“Subsequently, we will produce five micro CHP plants, which will also be put into operation among professional users. We are still in the early process of the technological launch and need to gather as much experience with these systems as possible,” says Jesper Themsen.

The micro CHP plants are based on Topsoe PowerCores™. Dantherm Power will build the rest around them. It should be possible to add natural gas purified of sulphur and with the correct pressure. There must be supply of fresh air, a heat exchanger and a heat store. The necessary electronic control for the micro CHP plant to be connected to the grid will be incorporated.  And the micro CHP plants will have to gain a safety certificate.

Currently, micro CHP plants are the size of an overgrown American fridge. “we can make smaller, but to start with we’re not going to make them too compact so that it is easy to monitor and maintain the various parts of the plant,” says Jesper Themsen.

Dantherm Power expects to have seven micro CHP plants in operation in early 2011, which will be in operation throughout the entire heating season and well into spring 2011.

In September 2011, Dantherm Power plans to produce 15 new micro CHP plants based on experiences from the first seven. “They’ll be so reliable that we can install them in private homes in Southern Jutland,” says Jesper Themsen. “In 2012, we believe that SOFC micro CHP plants will be affordable and have the desired properties to allow members of the public to replace their old home furnaces with a SOFC micro CHP plant.”

Jesper Themsen expects a major breakthrough to happen in 2013 – 2015 and that many Danish families in 2015 will be having a SOFC micro CHP plant, which will not take up more space than a dishwasher. Fuels will initially be natural gas, later it could be methanol and liquefied petroleum gas. In the long term, biofuels could also prove useful.

“We are having a long-term strategic cooperation with Topsoe Fuel Cell on SOFC micro CHP plants.  We are working together to make SOFC fuel cell power plants a commercial success,” says Jesper Themsen.

In the long term, Jesper Themsen imagines that fuel cell power plants will replace generators powered by diesel or gas.

They are used as backup in countries where the grid is not as stable as in Denmark. Here they are in operation continuously for many hours with the purpose of using the fuel efficiently.

For more information visit the Risø DTU National Laboratory for Sustainable Energy.

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