A leading light
Fuel cells offer a great deal of promise in a variety of applications. E&T visits Finland where a key demonstration project hopes to prove this 'disruptive' technology is on the verge of commercial reality.
In 2006, a Finnish town saw an opportunity to demonstrate the use of fuel cell technology to generate heat and power for some homes being built to showcase new architectural styles. Now, as engineers prepare to start operating the plant, the seemingly small-scale project has become a symbol of progress in the fuel cell field, and of the efforts being made by the commercial and public sectors alike to bring the technology to commercialisation.
The project in question is just one in a myriad of demonstrations around the world covering a wide range of fuel cell technologies in a variety of applications, but the company behind it believes that it is a major step forward in the development of solid oxide fuel cell (SOFC) technology for stationary power applications. Not only will the fuel cell power plant provide heat and electricity to several homes at the site on the outskirts of Vaasa, Finland, it will highlight the challenges that need to be overcome to get commercial fuel cell units to the mass market.
The project is also unique as it is the first demonstration of a fuel cell-based power plant running on landfill gas. The 20kWe unit was installed at the site of the Vaasa Housing Fair in 2008 and is a key element of the SOFC commercialisation plans of its developer, Wärtsilä.
"The Vaasa project is one of four active projects that we have in the fuel cell field," notes Erkko Fontell of Finland-based equipment manufacturer Wärtsilä. "We see it as an important research installation that will enable us to investigate the performance of our technology and gain experience with landfill gas."
Proponents of fuel cells argue that the technology is already commercialised. Small fuel cells are already in use in a variety of portable applications, including caravanning and other leisure activities. Such applications, while small in terms of market size, are crucial to the development of the technology and its familiarisation by end-users.
Market intelligence firm Fuel Cell Today says that commercialisation of fuel cells began in 2007, and annual per-kW cost reductions of between 10 and 20 per cent are being achieved. It recently reported that some 18,000 fuel cell units were shipped in 2008, a rise on 2007, when 12,000 units were shipped.
Fuel Cell Today noted in its 2008 annual review that commercial opportunities mainly favour the low-temperature varieties such as direct methanol fuel cells (DMFC) and proton exchange membrane (PEM) fuel cells (see ‘Fuel cell technologies’ p52). In general, low temperature fuel cells are projected to be commercially available for major applications such as transport by around 2015. The high temperature technologies - including SOFC - are likely to lag behind, which raises the question, why are Wärtsilä and other fuel cell developers focused on SOFC?
"There are three reasons why we chose to focus our efforts on SOFC," explains Fontell. "Firstly, SOFC are fuel flexible: they can use hydrocarbons but don’t need hydrogen as a primary fuel, and this means that they do not require the development of hydrogen infrastructure in order to be deployed.
"As well as being high-efficiency, their high operating temperature makes them suitable for combined heat and power applications and this will meet our customers’ needs," notes Fontell, adding: "Although they are not as advanced as other fuel cell technologies, we believe that in the long-term they will be the more competitive option."
Solid oxide start
Wärtsilä embarked on its fuel cell development programme in 2000, seeing an opportunity to extend its product range with an advanced, low-emission technology. It is aiming to deploy solid oxide fuel cells in both stationary power and marine applications, and by 2004 had carried out its first hardware tests.
Wärtsilä won’t divulge information on its target date for selling a commercial fuel cell product but in its short fuel cell history, the company has already achieved several milestones. "In 2007, we demonstrated the largest stationary planar SOFC at our own facility in Espoo. It was a 20kW unit which operated for 1,000 hours," says Fontell.
That demonstration was a big step forward for Wärtsilä, a company best-known for its diesel and gas engines, as it had previously only tested a 5kW unit. The Espoo demonstration ran on natural gas, and so the latest installation at Vaasa represents a new challenge in the form of landfill gas.
SOFCs are fuel flexible because their high temperature operation allows them to reform fuels internally, eliminates the need for a precious metal catalyst, makes them sulphur-resistant and means that they are not poisoned by carbon monoxide. They can run on fuels such as biogas or coal gases, but the use of landfill gas at Vaasa has already brought problems for Wärtsilä.
"The Vaasa Housing Fair was held last summer , but we could not start the fuel cell then because of problems with the gas supply," explains Fontell. "There is a lot of variation in gas quality and quantity at the site and we have had to make adjustments to the power unit. We are currently in the commissioning phase."
The Vaasa installation uses landfill gas from the nearby Suvilahti landfill site, which is now equipped with 14 wells to extract gas. Wärtsilä constantly monitors the methane content of the landfill gas and controls its flow through normal flow control devices. While the methane content of natural gas is around 90 per cent, in landfill gas it varies from 35 to 60 per cent. The gas has to be cleaned before entering the fuel cell.
But while operating fuel cells on landfill gas is more technically challenging than using hydrogen, biogases have the advantage of being widely available at sites such as landfills, wastewater treatment plants and farms. At such sites, the gas would otherwise be emitted to the atmosphere or flared off, adding to greenhouse gas emissions.
When the cleaned landfill gas enters the fuel cell stack it is humidified, heated and fed to the anode side where the nickel catalyst reforms the gas into methane, hydrogen and carbon monoxide. When this gas comes into contact with the anode, oxygen ions created at the cathode migrate through the electrolyte to oxidize the hydrogen and carbon monoxide into water and carbon dioxide. The nickel catalyst promotes the reaction, and electrons generated at the electrodes move out through an external circuit, creating electricity.
Wärtsilä’s planar SOFC operates at a temperature of 750-850°C and uses a solid ceramic material - yttrium stabilized zircona (YSZ) - as the electrolyte. The anode is made of a similar material but is very porous, allowing the fuel to flow towards the electrolyte. The cathode material is lanthanum strontium manganite (LSM).
At Vaasa, any unused gas at the anode side is burned in an after-burner, and heat is extracted from the process by gas-to-water heat exchangers. The plant produces 14-17kWth for the local district heating network.
The fuel cell consists of 24 stacks, each generating 1.0kW dc current at close to 60Vdc. Power electronics convert the low dc-voltage up to 440Vac for distribution.
Wärtsilä’s partners in the project include the City of Vaasa, Vaasa District Heating, Vaasa Electricity, Vaasa Water, Sarlin Oy, Mateve Oy, Sonera and Suomen Lämpöpumpputekniikka Oy.
Fontell says that when the unit is fully operational, Wärtsilä will monitor the plant to understand and overcome the challenges of using a low-methane fuel. It will also enable the company to overcome other, generic challenges associated with SOFC technology, namely durability and cost.
Durability of materials will be a key factor in the commercialisation of SOFC technology because of the high operating temperatures. In addition to finding low-cost materials that can withstand high temperatures for a substantial period of time, more operational experience is needed. "The technology is still fairly new and the basic technology has not reached lifetime par," says Fontell.
On the issue of cost, it is the ancillary equipment in the power unit, rather than the fuel cell stack itself, which Wärtsilä is targeting. "It is generally accepted that the fuel cell stack represents one-third of the cost of the power unit," notes Fontell. "To get the costs down to a competitive level is a major challenge and our strategy is to get fuel cell units into the market in some volume and establish a supply chain so that we can benefit from economies of scale."
The Vaasa project is a classic example of how disruptive technologies such as fuel cells are gaining support at the local level, but Fontell acknowledges that this will not be enough to commercialise fuel cell technology.
"Not enough is being done [at national and European levels]," says Fontell. "The European Commission is providing €470m up to 2013 in its Framework Programme 7 (FP7) for fuel cell and hydrogen technologies, which falls very short of funding available in other regions such as the US and Japan."
His sentiments are echoed by Patrick Maio, executive director of industry association Fuel Cell Europe, who applauds the European Commission’s recent efforts to reorganise funding for the sector, but also expresses reservations about the Commission’s Joint Technology Initiative (JTI) on fuel cells and hydrogen.
Proposed in late 2007, the JTI is a public private partnership designed to bring hydrogen and fuel cell technologies to the point of commercial take-off. The private sector is expected to match the European Commission’s funding levels.
"The JTI is now the main instrument through which funds for fuel cells are channelled," explains Maio. "Its creation [in 2008] corresponded to a need to bring together a multitude of programmes and better coordinate them in order to prevent redundancy and repetition in research. The JTI will also help the industry to synergise, get a critical mass and pool resources.
"Fuel cells have not benefited from a budget increase through the JTI when you compare FP7 with FP6," continues Maio, noting that the JTI’s first Annual Implementation Plan (AIP) was developed very quickly and did not match the industry’s expectations because the funds were low. Maio is also concerned about the management process.
"The Commission needs to get excellence from the process and ensure that all interests are served," he says. "We cannot have two or three large players having a large influence on where funding goes… already there are some commercially advanced companies that are not involved in the JTI, yet other, less advanced companies are benefiting."
Initiatives such as the JTI represent "government push", but what is also needed is "market pull", says Maio. This could come in the form of tax incentives and mechanisms related to carbon dioxide emissions to get more fuel cell units into the market. Maio also believes that Europe’s large utilities should follow the public procurement example set by the US military.
"Public procurement would be a good driver as it would get unit volumes up and cost curves down," says Maio. "In the US, the military is embracing and buying fuel cell technology but this hasn’t happened in Europe. However, we do have large utilities that should have an obligation to buy and demonstrate this type of equipment."