Where does your electricity come from?
How your cooperative plans for and acquires the electric power you need.
While these are correct answers, you might wonder what makes up the electric power and how it gets to those delivery points.
The job of your electric cooperative, like all electric utilities, is to make electricity available to users on demand, 24 hours a day, every day, and to supply it in the most cost-effective way. Professionals working for your cooperative know how to forecast the demand for and use of electricity in the long term and the short term, and they plan on how to use the co-op's assets and equipment to provide that power on demand when consumers need it. There are three general kinds of demand or "load."
- Base load is the amount of power that a consumer uses 24 hours a day. It is the minimum amount of power that a utility must provide to meet demand. Base load power is generated at plants designed to operate all the time, producing a constant output, like nuclear-fueled generating plants. When planning, utilities consider base load to supply about 30 to 40 percent of a system's requirement.
- Intermediate load is the amount of power that a consumer uses a majority of the time, to turn on lights, charge electronic devices or run air conditioners during periods of the day. This is the power required to meet the system's remaining demand, generally 40 to 60 percent, and is generated at plants that run most of the time, like natural-gas fired generating plants, on a regular schedule, to supply what's needed between the base load and the peak load.
- Peak load is the power delivered at times of highest demand, comprising about 10 percent of a system's requirement. Peak load power is generated at plants that run when they are needed, making it the most expensive electricity to produce.
North Carolina's electric cooperatives in 1949 formed a cooperative, now operating as North Carolina Electric Membership Corporation, that supplies its member co-ops with electric power. NCEMC and the state's electric cooperatives engage in power supply planning and in managing demand. NCEMC and its 25 member co-ops own 61.5 percent of Catawba Nuclear Station Unit 1, and a 30.76 percent interest in the common facilities of the Catawba station in York County, S.C. — one of the most efficient base load generation facilities in the U.S., operated by Duke Energy.
NCEMC also owns and operates for most of the state's co-ops four peak load generating plants: two natural gas peak load plants, one in Anson County and one in Richmond County, capable of generating 600 megawatts combined; and two diesel-fueled plants, a 15-megawatt plant in Buxton and a 3-megawatt plant on Ocracoke, which produce electricity for peak demand times as well as for emergency demand during an outage in those areas.
The remaining electric power comes from contractual arrangements by which NCEMC and some individual co-ops buy power from other generating utilities including Duke Energy, Dominion Power, Southern Company and others in the region, as well as by contract with producers of hydroelectric, wind and solar energy. In total, the co-ops' energy supply "portfolio" includes power made at nuclear, natural gas, coal-fired and renewable energy-fueled plants. [See chart.]
As older fossil-fueled generating plants are phased out, newer ones coming online can produce electricity more efficiently and with fewer emissions into the atmosphere. But keeping up with demand comes at a price. Mike Burnette, NCEMC's senior vice president and chief operating officer, points out that the Southeast's growing population, retirement of older fossil-fueled generating plants and demand for electricity to power buildings, equipment and even vehicles is requiring new infrastructure (generating stations, transmission systems, local poles and wire) and upgrades to the existing grid. "As we phase out the older fossil fleet infrastructure that was built with 1950s dollars, the load is still there," Burnette said. "So we are adding assets with 2013 dollars."
The bottom line is that when it comes to acquiring and distributing electricity, cooperatives as not-for-profit utilities owned by their consumers are guided by their founding mission: to provide safe, reliable electricity at the lowest possible cost.