Wärtsilä hopes to provide the City of Vaasa with a 50 kW solid oxide fuel cell power unit – in time for its 2008 Housing Fair.
The unit, dubbed WFC50 by Wärtsilä engineers but not yet a commercially available product, would use gas from an old landfill site to provide heat and power to Vaasa’s electricity and distributed heat grid.
The size of the WFC50 would place it in the commercial, district and industrial customer range. “Many companies are looking at residential fuel cell applications, both with high temperature SOFC and low temperature PEM technologies,” says Erkko Fontell, General Manager of Wärtsilä Fuel Cell Group. “These provide 1-5kWe power and are designed to supply heat and power to individual homes.”
The high temperature SOFC technology is more suited to the commercial and industrial market, Wärtsilä believes. “We are now focusing on 20-50kW demonstration units. After this we will develop the technology towards 200-250kW unit size. A 250kW unit could then be “repeated” for applications of around 1 – 5MW,” says Fontell.
“Solid oxide fuel cells such as the WFC50 are best used in parallel with the grid to provide combined heat and power (CHP) with high efficiency and reliability” he says. “High operational temperature of 750°C is most suitable for in continuous operation and provides high grade exhaust heat to a number of applications. In grid parallel mode the fuel cell unit can increase reliability by providing power to the critical equipment during grid disturbances.”
However, the dream of a town run by fuel cell power may be some years away commercially, Fontell warns. “This technology is in early demonstration phase where a low number of units are manufactured at high cost. If you wanted to buy a unit today, it would cost around US$10-20000 per kW, which is still far from the target level.”
To be competitive, Fontell estimates a fuel cell would need to cost no more than US$2000-2500/kW – forecasts for 2015-2020 show the price falling to US$1000/kW, so the technology has potential to become competitive. “But the cost development depends on both how the technology proceeds, and how fast the manufacturing volumes can be increased,” says Fontell.
At present, Fontell’s team is working with a WFC20 alpha-prototype, rated at 20 kWe. The unit will be operated at Wärtsilä’s fuel cell laboratory in Finland for the rest of this year. The unit will provide electricity and heat to the power and heat grids respectively – the first time a solid oxide fuel cell will have been used in such an application in Finland.
Wärtsilä, normally associated with reciprocating engines, has been developing fuel cell technology for decentralised power generation and marine applications since 2000. Wärtsilä’s existing SOFC system is based on the use of natural gas or methanol and lower sulphur diesel oil. The company is also examining the feasibility of using the technology with other liquid fuels.