Fuel cell technology is inching ever closer to commercialization in the electric power industry, with frequent annoucements from developers regarding new breakthroughs, projects and products. But a number of key obstacles remain to the widespread implementation of this technology.
Gero Di Piazza
In mid-September, NEC announced in Japan that it has developed a new prototype fuel cell powered laptop, which is twenty per cent more efficient than an earlier version launched in June. The newly developed fuel cell boasts the world’s highest output density of 50mW/cm2. The fuel cell features high power generating efficiency through the use of carbon nano-horns, a kind of carbon nanotube, as electrodes.
The announcement by NEC is just one of hundreds made by fuel cell developers each month concerning new breakthroughs, products, projects and collaborations. This illustrates not only the wide variety of applications that fuel cells are suited to, but also the speed of development in this industry. And whether developing fuel cells for stationary power, mobile power or military applications, developers are consumed by one overriding goal ” reducing the cost of fuel cell production.
Electricity from fuel cell-based power plants is known to be expensive relative to electricity from conventional power plants. All fuel cell developers, however, firmly believe that the technology has a clear role to play in future power systems: they argue in favour of their reliability, efficiency and environmental performance. They are versatile and can play a role in enhancing electrical grid security.
Fuel cells are trapped in a ‘chicken and egg’ situation, however: their cost is preventing widespread uptake of the technology, yet large-scale production of fuel cell units would enable a reduction of unit cost, and thus make them more commercially palatable. Some industry commentators believe that this is one of the main reasons why the uptake of fuel cells has been slower than was predicted ten years ago. Many believe that more funding is required to overcome this barrier.
A fuel cell works on the same principle as a battery but is continually fed with fuel
Fuel cells are being developed and manufactured for a wide variety of applications: military applications are expected to become a large market for fuel cells, as are mobile electronic devices such as laptop computers.
Development of fuel cells for the transportation industry is big business, as is that for stationary power systems for the residential and utility market.
A fuel cell works on the same principle as a battery but is continually fed with fuel. An electrochemical reaction, in which oxygen and hydrogen combine to form water, creates an electric current. There are several different types of fuel cell but they are all based around a central design which consists of two electrodes: a negative anode and a positive cathode. These are separated by a solid or liquid electrolyte that carries electrically charged paricles between the two electrodes. A catalyst, such as platinum, is often used to speed up reactions at the electrodes.
There are five main types of fuel cell technology:.
Alkaline: These fuel cells operate at low temperatures (80à‚°C) but have a low power density. They are the cheapest type of fuel cell to manufacture. Efficiency is about 70 per cent, and outputs range from 300 W to 5 kW.
Phosphoric acid fuel cells (PAFC): These are currently the most commercially advanced type of fuel cell, and use phosphoric acid as the electrolyte. Efficiency ranges from 40 to 80 per cent, and they operate at a temperature of 150-200à‚°C. There are currently a number of working PAFC power plants in operation around the world with outputs ranging from 0.2-20 MW.
Molten carbonate fuel cells (MCFC): The high temperatures (650à‚°C) that these fuel cells work at means that they are able to internally reform hydrocarbons and generate hydrogen within the fuel cell. The excess heat generated can also be harnessed and used for space heating and other applications. Their high efficiency and high power density mean that they are attractive to power generation applications, and designs of up to 100 MW are thought to be on the drawing board.
Solid oxide fuel cells (SOFC): These operate at high temperatures (1000à‚°C) using a solid ceramic electrolyte. Like MCFC, external fuel reforming is not required so they can use hydrocarbon fuels directly. Efficiency is about 60 per cent, but the materials used are expensive relative to other fuel cell types.
Proton exchange membrane (PEM): PEM fuel cells work with a polymer electrolyte in the form of a thin sheet. They operate at low temperatures (80à‚°C) and have a high power density and so are suitable for residential applications. Efficiency is usually around 40-50 per cent, and they can vary output to meet demand.
Ready to hatch
Many fuel cell developers say that the fuel cell market is about to hatch. This air of confidence could indicate that fuel cell development is finally coming of age, and that manufacturers are starting to concentrate on the marketability aspects of the technology, rather than on technological breakthroughs concerning the general design of their products.
Daniel Reinhardt, spokesman for MTU Friedrichshafen, compares the fuel cell development progress made by the automobile industry with that made by the power industry. He says: “[The power industry] is meeting its objectives because we are not weight or volume critical; these are the two things we don’t have to care about whereas in the auto indstry these factors are critical.” Reinhardt adds that with those issues aside, his company can focus on unit efficiency and bringing costs down.
In terms of meeting timeline objectives, Reinhardt adds: “We are ahead of our own schedule and we see the start of 2006 as the date of series production of our HotModule fuel cell. We even have a couple of orders pre-placed.”
MTU is based in Germany and much of its work is based on the market for fuel cells in Europe. Germany has been the centre of European fuel cell development, with a number of developers choosing to be based there as well as test and demonstrate their technology there. MTU has recently announced a partnership deal with RWE Fuel Cells. A new joint venture, called MTU CFC, will attempt to launch MTU’s fuel cell product into the market using RWE’s customer base and marketing capabilities. MTU will focus on R&D in the joint venture.
Companies in Japan, Europe and North America have led the way in fuel cell development
Mark Cropper of Fuel Cell Today concedes that the fuel cell market has not progressed as fast as most predicted but notes that the industry is growing in size. In the past two years, he says, the amount of fuel cell companies has at least doubled.
“The fuel cell market is technically very challenging, and it is a slow moving industry in terms of adoption. But also, it is very difficult to encourage people to adopt new technology. We have had 100 years of the internal combustion engine and getting people to switch is not easy.
“The most important thing to realize in an industry like this is to get the price to drop. But to get the price to drop you need a certain amount of volume ” it’s a classic Catch-22 situation. The upshot of that is, to get something to take off, is actually going to require some sort of external driving force. That could be legislation that stipulates you have to have a certain amount of capacity using fuel cells, for example.”
UK – no way
Cropper laments that there has been little fuel cell development in the past ten years in the UK, with the exception of one stationary fuel cell that supplies power to the residents of Woking, in Surrey (southeast England). It is a council-backed initiative. This is the UK’s first and only large stationary commercial fuel cell project. Cropper notes: “Over the past decade, they have developed their own private wire energy grid, which is independent of the national grid. But the amazing thing about it is its competitiveness on price, which makes it a fantastic case study.”
There are currently no manufacturers in the UK that are making the large stationary power systems, and certainly not every power plant equipment manufacturer has eagerly entered the fuel cell development market. Such companies are put off by the large investments required for fuel cell research and development, and perhaps prefer to adopt a ‘wait and see’ strategy: let other companies do the R&D work and then will consider entering the market when the technology is seen as being more commercially viable.
Japan and the USA are large funders of fuel cell development activity. The recent blackout in the US is also likely to be good news for developers there as the country seeks ways of enhancing grid reliability through distributed generation solutions. In Japan, support for fuel cell development has increased over the last two decades, driven by energy security issues and a growing market for distributed generation products in the commercial and industrial sector.
Other major issues that fuel cell developers are working to overcome include the cost of electrolyte, membrane and, in particular, catalyst materials. Ongoing research and development is helping to reduce costs in this area, and economies of scale from series production will also help to lower cost.
In the low-temperature fuel cell types (e.g. AFC systems), pure hydrogen is required as a fuel to prevent poisoning of the catalyst by carbon monoxide and other impurities. More tolerant catalyst systems are the focus of current research into this problem. High temperature systems are resistant to carbon monoxide poisoning as this is readily oxidised to carbon dioxide, but can be susceptible to sulphur content in the fuel.
But the bottom line in this industry appears to be volume: the more widespread the uptake of fuel cells is, the more likely the industry is to benefit from economies of scale and series production. One way forward is to encourage the uptake of fuel cells through policy and legislation, as many countries have already done with renewable energy.
Implementation of fuel cells in this way will help to generate interest and grow confidence in the technology. Working in favour of fuel cell technology at least is its versatility and environmental benefits, and the belief by its proponents that it has a strong role to play in future electric power systems. But however long it takes to overcome the few remaining barriers to commercialization, it will be well worth the wait.