Wind power demands ‘smart grid’

Wind power is coming to Virginia. We are not sure where, or when, but signs of arrival are here. Will we also get a "smart grid?"

Virginia has two regions of satisfactory wind for powering large turbine electric generators. One is along the ridges of the mountains of western Virginia; the other is in the Chesapeake Bay and along the Eastern Shore.

Dan Charles, writing in the latest issue of Science magazine, says electricity from renewable energy might be desirable, but it is tough to deliver on its promise.

Wind power is a supply-side source of electricity. That means when the supply of wind is adequate, wind turbines produce power. Solar arrays, another renewable-energy power source, also are on the supply side. When the sun shines, they make electricity.

Our traditional sources of power are demand-side generators. When customers ask for more electricity -- by turning on a clothes dryer, for example -- the power company recognizes the additional demand and can meet it.

Meeting demand means increasing the output of a nuclear plant, or feeding more coal into a coal-fired generator, or increasing the gas supply to a gas turbine. All are highly sensitive to demand.

This difference between wind and nuclear, for example, was highlighted by Charles' story of turbines in west Texas. In February 2008, they were busily spinning in the wind, generating 2,000 megawatts of electricity. In three hours, the wind dropped unexpectedly and the wind-generated power decreased 75 percent. Only by quickly cutting off customers -- reducing the need by 1,200 megawatts -- was the power company able to preserve the integrity of the electric supply.

A smart grid is a yet-to-be-constructed nationwide idea for delivery of electricity.

At each point along the way, from generators and wires to individual homes and businesses, the electric grid would be equipped with computers and sensors to report its health and its needs.

In part, a smart grid could better equip us to use renewable-energy sources -- either by cutting demand (turning off our clothes dryer for a while) or routing power to some means of storing it.

In Virginia, we have a power storage facility -- the Bath Pumped Storage Facility operated by Dominion Power. By pumping water up to a high reservoir, Dominion is able to store its potential energy for use during peak loads, by running water turbines.

One ingenious design for future storage of electric power would use the batteries of electric cars, storing excess energy to be used not by the car but by the electric grid.

The next steps in energy delivery will be tricky. How would you install the smart grid? How do you adapt the grid and consumers to sudden shifts in energy supply from renewable sources? How do you make the routine supply of cheap energy as easy in the next century as it has been in the past?

Virginia's science Standards of Learning cover energy and its transformations beginning with energy conservation in kindergarten. The study of renewable and nonrenewable energy sources begins in 3.11.