The utility company Baden-Württemberg EnBW Energie AG is expanding its state-wide program to promote the use of fuel cell technology for the supply of energy in homes. In addition to its work with high-temperature solid oxide fuel cells (SOFC), EnBW is now to start tests with low-temperature polymer electrolyte membrane fuel cells (PEMFC) for use in single-family homes.

The technology for the project is being provided by european fuel cell GmbH, a member of the Baxi Group. Featuring an electrical output of 1.5 kilowatts and a thermal output of 3 kilowatts, the low-temperature PEMFC offers an ideal source of energy for single-family homes. This so-called beta prototype is the first fuel cell system of this type to be installed in a private household in Germany, and thus tested under everyday operating conditions. The project is based on a contract concluded by the two companies. "Fuel cells are a key technology for the future," explains Prof. Thomas Hartkopf, EnBW Board of Management member for Technology. "In the medium term, they can provide an economical and ecological way of generating power and heat on a decentralized basis. Our activities are designed to promote the market launch of fuel cell systems, and thereby greater use of this environmentally friendly technology."

Fuel cell technology represents a key area of innovation at EnBW. To date, the utility has installed and is operating 18 fuel cell systems. Of these, 17 are being used to provide energy in homes and one is being used in the manufacturing industry. "The strength of the fuel cell lies in its versatility, high efficiency and the fact that, compared to conventional technologies, it produces substantially less harmful emissions at the point where the energy is generated," says Hartkopf.

Although all fuel cells function in a similar manner and convert hydrogen, as a source of energy, into power and heat by means of a controlled electrochemical reaction, the actual application of this principle can vary considerably. The SOFC, for example, operates at around 900° Celsius, the highest temperature of any fuel cell. While this places great demands on the materials used to construct the fuel cell, it also radically simplifies the processing of the fuel gas. EnBW is currently operating 16 systems from a pilot series of this type.

By contrast, the PEMFC operates at much lower temperatures — from 70° to 90° Celsius. Lower operating temperatures and a correspondingly simplified fuel cell design offer the prospect of more attractive manufacturing costs. On the other hand, low-temperature fuel cells have to be operated with hydrogen of a high purity. For this reason, more sophisticated technology is required to convert the natural gas used as a primary fuel into the hydrogen needed to power the fuel cell. Both types of fuel cell run on hydrogen-rich natural gas that has been suitably processed beforehand, and both pose no problems when it comes to installing them in buildings, just like a conventional gas-fired condensing boiler. "Our aim at EnBW is to test this pioneering technology under everyday operating conditions and to enhance its efficiency and ecological potential," says Hartkopf. The experience gained by EnBW in its various projects will certainly help to advance fuel cell technology and is to be evaluated in cooperation with manufacturers and research institutes.

It was back in late 2000 that EnBW first began to pursue an integrated strategy to promote this highly promising technology among its customers. Since then, the utility has continuously expanded its expertise in this field, running a host of fuel cell projects with systems of varying outputs, ranging from one kilowatt to as much as 250 kilowatts of electricity. As always, the objective is to evaluate whether specific applications of this technology are likely to offer a feasible alternative for generating power and heat on a decentralized basis in the foreseeable future.

In another project, at a Michelin tire plant, EnBW is studying the use of fuel cell systems in industry. Here, a fuel cell unit produces not only electricity but also steam at 200 Deg Celsius, which is used to vulcanize the rubber for truck tires. The fuel cell is fully integrated in the conventional system used for generating heat at the plant, which should enable EnBW to gather valuable experience in terms of how the various systems harmonize with one another.
Since the start of 2002, EnBW has also been offering private customers a special fuel cell package called "EnBW Cell-Plus."

In addition to having a small-scale fuel cell generating unit installed in their basements, the households selected to test this pioneering technology also benefit from a full line of services from EnBW, ranging from initial planning to the actual supply of heat and power. In other words, EnBW is responsible for installing, operating and monitoring the units in customers’ basements. In an arrangement similar to a leasing contract, consumers only pay for the thermal energy they use for heating and hot water. The electricity generated by the unit is either used directly by the customer or fed into the grid. In keeping with its pioneering role in this field, EnBW carries both the technical and financial risk involved in operating these prototype and pilot systems. It’s the technology of the future — in operation today.