Shift to solar and wind power could threaten U.S. electrical grid

By Matthew L. Wald
Published: November 10, 2008

WASHINGTON: Adding electricity from the wind and the sun could increase the frequency of blackouts and reduce the reliability of the U.S. electrical grid, an industry report says.
The North American Electric Reliability Corp. says in a report scheduled for release Monday that unless appropriate measures are taken to improve transmission of electricity, rules reducing carbon dioxide emissions by utilities could impair the reliability of the power grid. The corporation is the industry body authorized by the U.S. government to enforce reliability rules for the interlocking system of electrical power generation and transmission.
Such carbon-reduction rules are already in place in 27 American states and four Canadian provinces, and new ones could be mandated nationally in both countries. They may force changes in the utility industry, the group said, including the shutting down of coal plants that are located near load centers, and substituting power from wind turbines or solar plants in remote areas.
These actions would impose new demands on a transmission system that was never designed for large power transfers over extremely long distances.
The group also said that the carbon emission rules could increase reliance on natural gas, making power generation vulnerable to supply interruptions.

Carbon emission initiatives are the "No. 1 emerging issue" for the grid, according to Rick Sergel, president and chief executive of the group, which is based in Princeton, New Jersey. Renewable energy can form a larger portion of electricity supplies without reducing reliability, Sergel said, but not without investments in transmission.
The overhauled electric system that has emerged in the last two decades already has inadequate transmission capacity, he said. Independent power producers have built generating stations that compete in a geographically vast marketplace to serve distant consumers. "The transmission system is being used closer to its limits more of the time than at any time in the past," Sergel said.
The report was based on information from 50 utilities, power generators and other electric system participants. It quotes Kenneth Farmer, executive director of the Beauregard Electric Cooperative, of DeRidder, Louisiana, saying, "It appears that greenhouse gas issues and electric utility reliability are on a collision course."
The report calls for construction of new power lines, which has become more difficult in some regions because of the diminished clout of utilities and the growing strength of preservationists trying to protect rural areas. Building new lines to reach distant areas with great potential for power generation will take a new approach to planning, the report said.
One solution, it said, might be greater use of "demand-side resources," or deals with customers to cut consumption in periods of high energy use. In these arrangements, some retail customers agree to have equipment like central air-conditioners or swimming pool pumps controlled by utilities, which can limit their use at peak times. Some big customers, like factories, may voluntarily shut down on peak use days. Both groups get a discount or a regular payment in exchange for becoming "interruptible."
Such measures can relieve pressure on generating stations and transmission lines, but require reliable integration with the transmission system, the report said.
Some experts say they think that imposing hard limits on carbon dioxide emissions could threaten the reliability of the power supply.
Peter Carney, an environmental engineer at the New York Independent System Operator, which runs the bulk power transmission system in New York, said that such problems could result from the Regional Greenhouse Gas Initiative, of which New York is a member. Under that agreement, utilities get allowances for carbon emissions. But under some conditions — a spike in demand because of severe weather, or the lengthy shutdown of a nuclear plant — the only way to obtain more power could be to burn more coal, increasing carbon emissions. It is not clear how such conflicts would be resolved.