Biodiesel is widely accepted as a fuel for transportation fleets, but the idea of using it for backup power generation has, to put it mildly, remained stationary. However, despite challenges, the idea has merit and there appears to be a growing interest in running standby generators on biodiesel blends to produce green power.
Standby generators, also known as backup generators or emergency generators, are commonly found at "critical facilities"-airports, hospitals, military bases, police stations, prisons, telecommunications centers and water treatment plants. Standby generators are present in all different types of manufacturing: mining and industrial facilities for chemicals, food processing, ore processing, pharmaceuticals, printing plants and semiconductors. Other hosts for standby generators include bank and credit card facilities, high-rise apartment buildings, laboratories, office towers and universities. Finally, small standby generators are found in millions of homes and small businesses across the United States.
There are an estimated 100,000 standby generators in the United States serving industrial and commercial facilities. Collectively, these standby generators represent about 10 percent of total U.S. generating capacity.
The large majority of standby generators are diesel engines, which provide independent, on-site energy sources. The large majority of these diesel engines sit idle all year, except for a few dozen hours when tested or operated for short-term power outages.
Increasing use of standby generators
The steady growth in the demand for power coupled with the challenges of siting massive new power plants and highly visible transmission lines is making decentralized energy resources more popular. The electric industry term is called "distributed generation," as distinguished from large "central generation" plants.
Standby generators are one type of distributed generation resource. Standby generators can start and reach full load in less than 15 seconds. Standby generators may be integrated directly into the power grid, but most are wired to meet specific electric needs at their host facility.
More and more utilities are working with their large commercial and industrial customers to operate standby generators in order to help meet peak loads on the power grid. Customers are being paid to generate power for up to 100 hours per year; this is on top of the normal hours of power generation for testing and emergency outage purposes. In practice, the use of standby generators in anticipation of power shortages should prevent such blackouts. Utilities are asking customers with as little as a half-hour notice to operate standby generators for typically about three hours at a time on hot summer afternoons or cold winter mornings.
Biodiesel in standby generators
Environmental restrictions can inhibit the use of standby generators for peak load management. Standby generators are normally exempted from air emission requirements as long as they are operated only for emergency purposes when the power goes out. If standby generators are operated for power generation purposes in non-emergency conditions, such as to meet peak power needs on the electrical grid, more stringent permitting rules may apply.
Biodiesel may allow increased use of standby generators due to lower air emissions for most types of pollutants. Biodiesel also offers the opportunity to reduce soot deposits, unsightly exhaust gases and objectionable odors associated with diesel engines. Furthermore, biodiesel is less hazardous when spilled. All these benefits increase in importance for standby generators located near populated areas, which is typical.
While transportation fleets are experiencing a surge in the use of biodiesel, generation fleets are far behind. During the California blackouts of 2000 and 2001, a few standby generators experimented with the use of biodiesel. But these have been discontinued, except for a hospital using B100 with an additive to reduce nitrogen oxide emissions.
Currently, one of the leaders in the use of biodiesel is the U.S. National Park Service (see Biodiesel Magazine, July/Aug. 2004). An overlooked aspect of their leadership has been to deploy biodiesel in standby generators as well as transportation fleets. Standby generators are burning B20 at Channel Islands, Glacier and other national parks. Mt. Rainier National Park is using B50 in two engines, each sized at 90 kilowatts (kW) or about 120 horsepower. Significantly, each engine runs for two weeks continuously and then is shut down for maintenance, while the other runs for a two-week period. They are located in a remote part of the park that is beyond the power grid and is open only in the summer months.
A utility in Minnesota has been using B2 to B5 in a fleet of standby generators to meet peak power requirements for several years. A utility in Tennessee is embarking on an experiment with B100 with a large 2,000 kW generator that will be tested for 1,500 hours of continous operation starting in early 2005.
A pilot project is underway with a target of 16 standby generators in the Olympic Peninsula of Washington State. The generators are located at facilities such as police stations, water treatment plants, hospitals and casinos. With the permission of the facility owners, the generators will be asked to operate for up to 100 hours per year with B20 or B100 as a way to defer capacity additions to the electric power systems.
The project is being sponsored by Bonneville Power Administration and an assessment on the use of biodiesel may be found at
www.bpa.gov.There are significant questions about using biodiesel in standby generators that should be clarified over the next year. More needs to be learned about engine performance, fuel storage and emissions, comparative costs, regulatory acceptance and customer attitudes. At the same time, opportunities may also grow over the next year in the use of renewable energy credits and mandates for utilities to produce more green power.
Larry B. Barrett is president of Barrett Consulting Associates Inc. He serves utilities and other energy related companies in new product planning and market analysis. He may be reached at (719) 634-4468 and
lbbarrett@aol.com.