U.S. ‘smart grids’ would save energy, money

Posted Aug. 19, 2009, at 8:19 p.m.

The Island of Malta, in the middle of the Mediterranean Sea, has a population of nearly half a million people on an area of 186 square miles. Maine has a population of a bit more than 1 million people with an area of 54,560 square miles. Malta has no indigenous sources of energy; everything must be imported. The fresh water supply is limited and electric energy must be used for the desalinization of seawater.

The only source of electric energy is from 250 megawatts of fossil fuel generation. The management of this generation calls for a “smart grid.” If the weather is mild and the need for air conditioning modest, they will run the desalinization plant to build the water reservoir. As a heat wave drives the air-conditioning load, the power generation station, through a wireless computerized system, can override thermostat settings in hotel rooms to reduce the load. Water heaters and refrigerators can, by radio control from the power plant, be put on temporary “standby.”

Except for a few utility arrangements with industry, such “smart grid” load control is not used in the United States. This will change. On the average, half of the U.S. electric generation capacity is not operating. As the demand for electricity changes hour by hour, plants are added to the grid or shut down. On any particular day, if demand increases, less-efficient units are started. If, on the other hand, we could control the load, such polluting and inefficient plants could remain idle. As wind and solar energy is added to the generation grid, load management will become more important.

Consider a mild, windy autumn day. The need for heat and air conditioning is minimal. The hydro and nuclear stations can supply all electric power needs. What’s to become of the wind energy? Other items could use it, such as domestic water heaters with additional storage or ice-making machines to buffer an air-conditioning load.

About 25 percent of all electric energy is used to operate vapor-compression systems: air conditioners, refrigerators, freezers, etc. As a typical domestic refrigerator leaves the factory, it must be capable of efficient operation in Houston. Such units are oversized for less demanding climates such as New England. The compressor speed could be changed by a signal from the power grid, the efficiency of the refrigerator would be increased and the demand on the grid decreased.

Someday, Central Maine Power Co. may say to your refrigerator: “You are not in Houston anymore.” Such a conversation will be technically challenging and bureaucratically daunting. The National Institute of Standards and Technology will be needed to manage the “interoperability” of various systems; the U.S. Department of Energy must have overall management; the Federal Energy Regulatory Commission must deal with the National Association of Regulatory Commissioners; the Federal Communications Commission must not be neglected; and even the Maine Public Utilities Commission will be in the act.

If this entire system can be made to work, you may see on the background of your computer screen the words: “At this moment you are paying 50 cents for each kWh being used,” and you can scream at the kids to shut off the extra TV set.

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