Supplementing Electric Utility Power
With Fuel Cells in Brazil

International authors came to the 37th Intersociety Energy Conversion Engineering Conference, July 29-31 in Washington, D.C., to discuss fuel-cell technology and opportunities. They brought many new ideas for solving problems like California’s power shortage that necessitated roving blackouts to avoid collapse of the U.S. West Coast power transmission network.

Growing electric loads and a dearth of new power plants have created severe worldwide power shortages and a crisis in Brazil. Luciane Neves Canha described the analysis and modeling showing that the crisis could be relieved in a fast and practical manner by placing fuel cells at optimum locations and carefully scheduling their operation (1). Acquiring the data for the model and optimizing the model took a lot of effort. For example, the peak load time varies among power consumers. In some residential neighborhoods of Brazil the peak load occurs when people shower with electrically heated water. There the fuel cells can be best located where their heat losses can be used to heat water.

The growing electric-power demand forces construction of large generation systems, transmission lines, and big substations, plus ever-greater power-transmitting capacity of the distribution networks. On the other hand, the world appeal for environment protections, and reduction in pollutant-gas emissions, have been factors that limit the construction of large thermal and hydroelectric power plants. Canha observed that the solution to this impasse is the incentive use of renewable energy, and generating power with efficient alternatives. Having huge power-generating plants running at part-load, on-line, and waiting for an expected peak load may not reduce overall pollutant emissions.

Advantages of Fuel Cell Power

For carrying load peaks the hydrogen-consuming fuel cell has many advantages. The hydrogen can be produced by electrolysis of water during an electric utility’s non-peak-load periods. At late night an otherwise unloaded hydro plant could generate power for the water-electrolyzer in a hydrogen-producing station. During peak-load periods a reserve power-generating capacity, often 5% of the load, has to be on line. This extra capacity could be routed to hydrogen-producing electrolyzers, which could be turned off in a fraction of a second when a load crisis develops. Also, fuel cells can start generating power within a few seconds after they receive a power-up command. The efficiency of the electrolysis process is high, and depending on the current cost of electric energy, the cost of produced hydrogen can become viable.

Factors such as temperature, pressure, and concentration of the reactants have a large influence on the output voltage, and consequently the efficiency of the fuel cells. To investigate these effects, Canha’s team developed a special electrochemical model of a fuel cell.

Modeling the Electric Loads of a Utility