Nuclear power: mainstay for S.C.

Anyone who believes that nuclear power in the United States is in a state of remission hasn't picked up on electricity generation in South Carolina recently. Our economy is poised for growth in years ahead thanks to the stellar performance of the state's nuclear power plants.

Nuclear power is South Carolina's energy mainstay. It accounts for 51.2 percent of the state's electricity, with coal a distant second at 40 percent, according to the U.S. Energy Information Administration. Safe and dependable, nuclear power supplies electricity to one out of every two homes and businesses in South Carolina, without producing any air pollution or greenhouse-gas emissions.

But what's eye-popping about newly-published data for nuclear plant performance in 2008 is the capacity factors - a measure of reliability — for two of the state's seven plants: Catawba 2 in Clover at 102.9 percent and Oconee 3 in Seneca at 101.9 percent.

Last year the average capacity factor for the 104 U.S. nuclear power plants was 91.1 percent. In other words, the plants were running more than 90 percent of the time, supplying large amounts of "base-load" electricity around the clock, seven days a week to residential, commercial and industrial customers. By comparison, average capacity factors for coal plants are about 70 percent, trailed by gas plants at 40 percent, wind turbines at 30 percent, and solar power, 20 percent.

Due to their high capacity factors, nuclear plants produce electricity at relatively less cost than alternative sources. In 2007, the latest year for which data is available, nuclear-generated electricity nationally cost, on average, 1.76 cents per kilowatt-hour. By contrast, coal cost 2.5 cents per kilowatt-hour, gas-fired power, 6.8 cents, and oil-fired power, 10.2 cents.

So how can a nuclear plant post a capacity factor that exceeds 100 percent? Think of availability. Capacity factor is the ratio of electricity produced in a given time period to the maximum that could be produced in that period at full rated power. The rated power level is determined by summer conditions when plant cooling systems are least efficient. In cold weather, many power plants can produce more electricity than their summer rating and, as a result, their capacity factor can top 100 percent.

Sixteen of the nation's 100-plus reactors achieved capacity factors greater than 100 percent in 2008. One of the reactors was the remaining unit at the Three Mile Island nuclear plant in Pennsylvania, which continued operating after its twin unit shut down following the TMI accident 30 years ago. It's clear in hindsight that nuclear utilities learned many valuable lessons from that accident - how to work together to improve safety and how to improve plant reliability. Much of the credit for this goes to William S. Lee, the late chairman and chief executive officer of Duke Power, who led the effort to create the Atlanta-based Institute of Nuclear Power Operations, which has helped train reactor operators and ensure plant safety.

South Carolina's nuclear plants have achieved a record of excellent performance in recent years, posting an average capacity factor of 91.8 percent over a three-year period between 2005 and 2007. The H.B. Robinson 2 plant in Hartsville had the highest capacity factor, at 96.3 percent.

Small wonder then that utilities are gearing up to build more nuclear plants. So far companies have submitted applications to the Nuclear Regulatory Commission for licenses to build and operate 19 reactors totaling 27,000 megawatts in new capacity. Among the planned plants are SCANA Corp./Santee Cooper's two-unit expansion at the Summer nuclear plant. The Department of Energy said recently that the Summer plant additions are among five planned nuclear plants that are in the running for $18 billion in government loan guarantees. The loan guarantees are critically important in obtaining financing for new power plant construction. They would be a small price to pay for affordable power, and not having to pay a premium for imported oil and natural gas.

Dr. Clint Wolfe, of Aiken, is executive director of Citizens for Nuclear Technology Awareness.