Are Supergrids the Answer?
Iceland Geothermal

Work is under way to send Iceland's vast geothermal resources to provide energy to Europe. (Photo courtesy of

By Jonathan Marshall

Will the future of electric power be dominated by radically decentralized “microgrids” and customer-owned, distributed generation?

Or will the traditional model of centralized generation, brought to customers over long transmission and distribution lines, get even bigger?

Answer: probably both.

With tens of thousands of Californians just in PG&E’s service area putting solar panels on their rooftops, it’s clear that distributed generation is here to stay and growing fast. But contrary to some “small is beautiful” advocates, supergrids might have their place as well.

Long-distance transmission grids are costly and challenging to site but can bring great economic and environmental benefits, as the North American Electric Reliability Corporation and the National Renewable Energy Laboratory concluded in major studies. Most obviously, they can carry renewable energy from areas of abundant generation but little population, like solar in the desert or wind in the Midwest and offshore, to major demand centers.

Second, and of great importance as utilities struggle to cope with increased quantities of highly variable renewable energy, transmission grids can draw power from dispersed regions to “blend and smooth” the local fluctuations of wind and solar energy, minimizing the need for investment in costlier remedies like battery storage.

Denmark, for example, is able to support its leadership in wind power by drawing on abundant and inexpensive hydropower from Norway and Sweden, through a regional interconnection, when the wind dies down. It exports excess wind power over the same grid to Germany and Scandinavia.

Even bigger grids are now in the planning stages, including Western Europe’s so-called “supergrid.”

Slated to cost as much as 30 billion Euros, this nine-country grid “would connect turbines off the wind-lashed north coast of Scotland with Germany’s vast arrays of solar panels, and join the power of waves crashing onto the Belgian and Danish coasts with the hydroelectric dams nestled in Norway’s fjords,” according to The Guardian.

Spanning thousands of miles, it “would solve one of the biggest criticisms faced by renewable power—that unpredictable weather means it is unreliable.”

Last month, Iceland’s electric utility announced plans to lay the world’s longest undersea power cable to tap into this supergrid, in order to sell abundant and clean geothermal power into the vast European market.

The supergrid will also interconnect with a giant renewable energy scheme called Desertec, a $400 billion project to turn North Africa into a solar powerhouse big enough to supply 15 percent of Europe’s electricity by 2050, via power lines crossing the Mediterranean (MedGrid). Desertec plans to launch this year with a 500 megawatt solar installation in Morocco.

Meanwhile, in the United States, Hawaii is studying a proposed undersea power cable to connect Oahu with wind farms in Molokai and Lanai, reducing the need for oil-burning generators.

Last month, Interior Secretary Ken Salazar said reviews are progressing on a proposed $5 billion undersea transmission grid to carry thousands of megawatts of offshore wind power between Virginia and New Jersey. Google is a major backer of the project.

And the Midwest Independent System Operator has been studying the viability of an $80 billion transmission project to supply as much as 20 percent of the East Coast’s electricity needs with Midwestern wind energy.

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