Industrial, and residential applications including cogeneration, heating, and air-conditioning. When by-product heat is used, the total energy efficiency of fuel cell systems approaches 85 percent.)

Sizing Plants to Meet the Load

(The fuel cell stack is the basic component of a fuel cell power plant. Stacks are

combined into modules, and plant capacity is determined by the number of

modules. Individual modules can go from idle to full load in minutes.

Modular plants can help planners overcome many difficult expansion problems. Mass-assembly construction techniques and shorter lead times for installation

reduce the capital risk in adding generating capacity. Capacity can be better matched to load, and the high costs of large new plants with underutilized capacity

can be avoided.

Modularity also produces a flat economy of scale: the cost per kilowatt is about

'the same in small plants as in large ones. And because electrical efficiency is determined by individual cell performance, the number of modules in the power plant has little or no effect on overall efficiency. As a result, fuel cell power plants offer the same advantages at 25 kilowatts as they do at 50 megawatts.

Reliability

Fuel cells promise to be one of the most reliable, if not the most reliable, power generation technology. They are now being used by hospitals, hotels, and telephone companies as part of critical uninterruptible power systems.

Putting Power Where it's Needed

The modular nature of fuel cells allows power capacity to be added wherever it's needed. In the typical central power configuration, additional capacity is sited at the central plant or at substations. In a distributed power configuration, capacity is placed close to the demand. In high-growth or remote areas, distributed placement offsets the high costs of acquiring rights-of-way and installing transmission and distribution lines. A distributed configuration also eases public concerns about exposure to electromagnetic fields from high-voltage lines.

Smaller scale distributed configuration power plants are perfect for commercial buildings, prisons, factories, hospitals, telephone switching facilities, hotels, schools, and other facilities. In these applications, consumers get the best of all worlds - high-quality power that is economical and reliable) On-site power conditioning eliminates the voltage spikes and harmonic distortion typical of utility grid power, making fuel cell power plants suitable even for sensitive electronic loads like computers and hospital equipment. And in many cases, utility grid backup reduces the need for expensive uninterruptible power supply systems.

Power Plants as Good Neighbors

Having few moving parts and requiring little on-site maintenance, fuel cell power

plants are reliable and safe, and can be sited in environmentally sensitive areas.

They are relatively small - a 2-megawatt demonstration plant in Santa Clara, California, is the size of a tennis court - and produce negligible noise. A 200-

kilowatt plant is about as noisy as an ordinary air conditioner. No fuel has to be stored on site. The "good neighbor" character of fuel cell power results in short permitting and licensing schedules for both indoor and outdoor installations.

Choosing From a Variety of Fuels

Fuel cells need hydrogen, which can be generated internally from natural gas, coal gas, methanol, landfill gas, or other fuels containing hydrocarbons. Although most market-entry fuel cell plants are fueled by natural gas, fuel flexibility means that power generation can be assured even when the primary fuel source is

unavailable.

Solutions that Meet Public Needs

As the most environmentally friendly source of fossil-fueled energy, fuel cell technology meets public demand for clean, quiet, and efficient power. Fuel cell exhaust is cleaner than the air of some cities. The low level of noise at a fuel cell installation makes it possible to hold a normal conversation while standing right next to the power plant. And safe, reliable operation reduces public concerns about siting, even in densely populated areas.