Powering the future

Fuel cell technology for power generation is becoming ever more popular. In December, for example, South Korea’s Posco Power, a unit of the mega-industrial conglomerate Posco, signed an agreement with Fuel Cell Energy of the US to buy two 4.8 MW DFC3000 power plant units. They will be sold to independent power producers and will be installed in 2009. Posco Power has now ordered 12.6 MW of fuel cell units since March 2007.

FuelCell Energy says its power plants are 47% more efficient compared to similar sized fossil-fuel combustion power facilities, which operate at 30-35% efficiency. This means that they deliver more power for each unit of fuel used, bringing savings on power costs and substantially cutting CO2 emissions.

A cleaner option

A fuel cell is essentially an energy conversion device that typically transforms hydrogen and oxygen into electricity and heat without producing emissions, thus reducing greenhouse gases.

As long as fuel is supplied, the cell will continue to generate power and, because the conversion of the fuel to energy takes place via an electrochemical process rather than by combustion, the process is clean, quiet and very efficient.

According to FuelCell Europe, an EU-based association that promotes fuel cells, the technology’s superior conversion efficiency and fuel flexibility means it can help to satisfy energy needs, improve air quality and reduce dependence on fossil fuels, while also increasing the use of locally generated power.

Multi-purpose

Fuel cells have a wide variety of applications, including providing heat and power for commercial or domestic use; powering buses, cars, ships and trains; and extending or replacing battery power in energy-consuming appliances, such as laptop computers and mobile telephones. These are the three main fuel cell market segments, defined, respectively, as stationary, transportation and portable applications.

In the portable sector, fuel cells have now reached a stage of sufficient maturity for commercialisation and are already available on the market. Their market commercialisation has been driven by the US and Asia, but mostly through R&D work carried out by Japanese companies such as Casio, Fujitsu and Toshiba, whose products are paving the way for mass market deployment.

Nevertheless, some issues still need addressing. FuelCell Europe says the main concerns are the durability of the catalyst used and its ability to reach a continuous and stable performance under active operating and passive conditions.

Electric cars

For transportation, proton exchanging fuel cells are seen as the preferred option. Fuel cells in this sector are attractive as they remove the reliance on oil and reduce emissions, as well as air and noise pollution. In Europe, several companies are investing in this area, including Chevron, DaimlerChrysler, DuPont, Hydrogenics and Shell Hydrogen.

But again there are challenges to increased deployment such as cost and endurance, together with a lack of refuelling infrastructure and public acceptance.

Germany’s Linde Group has estimated that it could cost up to 3.5 billion (US $5.1 billion) to build a hydrogen infrastructure of around 2 800 filling stations for the European car market, even though continued high oil prices would eventually offset the cost. The International Energy Agency (IEA), for its part, has said the costs would be high, but workable.

It is unlikely that the fuel cell vehicle will be commercialised for public use before 2010, but progress is being made. In November, at the Los Angeles Auto Show, Honda unveiled its FCX Clarity fuel cell vehicle and announced plans to begin limited retail marketing of it in the US from mid-2008.

The car is based on Honda’s V Flow fuel cell platform. The stack is used in combination with a compact, lithium ion battery pack and a single hydrogen storage tank to power the electric drive motor.

The fuel cell stack operates as the main power source. Hydrogen combines with atmospheric oxygen in the fuel cell, where chemical energy from the reaction is converted into electric power used to propel the vehicle. Additional energy captured through regenerative braking and deceleration is stored in the lithium ion battery pack and used to supplement power from the fuel cell, when needed. The vehicle’s only emission is water.

Honda hopes its FCX Clarity will help to boost “the real-world performance and appeal of the hydrogen-powered fuel cell car.”

All the major automotive manufacturers have a fuel cell vehicle either in development or in testing right now and several have begun leasing and testing in larger quantities. In November, Ford was awarded the IEA’s Clean Vehicle Award in recognition of it having achieved sales of more than 50 000 hybrid models worldwide. Other companies that have recently launched or soon plan to launch versions include: Hyundai, GM, Nissan, VW and Daimler.

Confidence in a future market for fuel cell vehicles is being supported by policymakers, particularly in the European Union.

The European Commission (EC) said in October that the approval process for hydrogen cars should be simplified in order to accelerate their arrival on the streets of Europe. Under proposed measures, hydrogen vehicles would be approved through the same system as conventional vehicles, avoiding “complicated and costly approval procedures.”

The EC has also proposed setting up a fuel cells and hydrogen joint technology initiative – a public-private partnership to be launched over the next six years with financial backing of 470 million from the EU and also a similar sum from the private sector.

The EC says the initiative would accelerate the development of fuel cell and hydrogen technologies to allow their commercial rollout between 2010 and 2020.

Meanwhile, interest from the defence sector, particularly by the Department of Defense in the US, for fuel cell use in aviation applications is growing and this has persuaded aircraft manufacturer Boeing to develop a fuel cell plane.

Onsite power

For utilities, however, it is stationary applications that are most relevant. The Fuel Cell Organization of the US has estimated that more than 2 500 stationary fuel cell systems have been installed in hospitals, nursing homes, hotels, office buildings, schools and utility power plants around the world. They are either connected to the electric grid to provide supplemental power and backup assurance for critical areas, or are installed as grid-independent generators for onsite service in areas inaccessible for power lines.

The organisation says that fuel cell power generation systems in operation today achieve a 40% fuel-to-electricity efficiency. And when used for cogeneration in large-scale building systems they can reduce facility energy service costs by 20-40% over conventional energy services and increase efficiency to 85%.

In stationary applications, fuel cells can be used for distributed power; off-grid power; back-up generator power; cogeneration of power/heat; grid peaking applications; and to power remote industrial operations.

The main technologies used in these applications are proton exchanging membranes and methanol direct fuel cells and, more recently, interest has grown in solid oxide and phosphoric acid fuel cells.

Stationary applications offer key advantages over conventional technology such as providing a reliable, uninterruptible supply of electricity, high efficiency, as well as noise and pollution reduction. They also facilitate the decentralised generation of power and can provide support to the grid during peak times.

Fuel cell research

Until recently, the US was considered to be leading the field in stationary fuel cell technology and its use, but Japan and Europe are now catching up. As with the two other main market applications for fuel cells, there are major challenges to mass deployment in power generation, such as cost, durability, and reliability. These issues are, of course, strategic research areas for fuel cell developers. But size and weight are less relevant considerations than in portable and transport applications.
 

Several major industrials are already involved in fuel cell projects. Chevron, for example, runs a commercially operating stationary fuel cell power plant in the San Francisco Bay Area in the US. The plant provides 200 KW of electricity, which is used to power some of the company’s offices.

In addition to providing a clean, quiet and reliable independent power source for critical electric loads and demonstrating the efficiency of the technology, Chevron says the plant allows it to monitor and analyse fuel cell performance relative to conventional power technologies in a commercial application.

Meanwhile, Rolls-Royce, which has studied several different types of fuel cells, believes the solid-oxide fuel cell technology is the best for stationary power generation applications, but says it could also be subsequently developed for transportation, military and marine uses.

The solid-oxide fuel cell is produced by screen printing on low-cost ceramic-type materials, using proven production processes and minimal exotic materials. It uses commercial-grade materials and has few components. On top of that, it is low in weight and has nearly doubled the simple-cycle efficiency of existing power generation technologies. The company has launched a US subsidiary to develop fuel cells further.

Rolls-Royce says its system, which contains less than 10 seconds of fuel supply at any one time, has great durability. Interestingly, this system can also be configured to use existing hydrocarbon-based fuels as well as alternative sources such as coal, gas and biomass. Rolls-Royce believes the solid-oxide fuel cell is particularly suited to local distribution networks and small, secure urban areas.

Political backing

The high political profile that fuel cells currently enjoy is, in large part, the result of global attempts to mitigate climate change. Fuel cells are increasingly discussed by policymakers as a low-carbon technology that will help to increase energy efficiency in power generation and to reduce emissions.

Several initiatives have been launched by governments and non-governmental organisations to support the technology and encourage R&D and private investment on the basis of widespread deployment over the next decade.

For example, the Clinton Foundation, announced in November that UTC Power, a unit of US firm United Technologies Corporation, would be an official supplier partner for the Clinton Climate Initiative. UTC is developing environmentally advanced power systems, including fuel cells for transportation and onsite power. The company said the appointment would help to bring fuel cell technology to commercialisation.

As FuelCell Europe puts it, no other energy generation technology offers the same combination of benefits as fuel cells. As well as low or zero emissions, the other advantages of this technology are high efficiency and reliability, multi-fuel capability, siting flexibility, durability, scalability and ease of maintenance. With this in mind, the fuel cell sector can only be expected to grow.