The North American power grid has experienced several blackouts recently, including a failure in August of 2003 that plunged some 50 million Americans and Canadians into darkness. According to a recent article in The Economist, experts predict more and bigger blackouts, unless the dumb electricity grid can be transformed into a smart, responsive and self-healing system—in short, an "Energy" Internet.
The real test of any network's resilience is how quickly and intelligently it can handle disruptions. Think, for example, of the Internet's ability to reroute packets of data swiftly and efficiently when a network link fails. The analogy is not lost on the energy industry.
Of course, the power grid will never quite become the Internet—it is impossible to packet-switch power. Even so, transforming today's centralized, dumb power grid into something closer to a smart, distributed network will be necessary to provide a reliable power supply—and to make possible innovative new energy services.
The good news is that technologies are now being developed in four areas that point the way towards the smart grid of the future.
|"Experts predict more blackouts unless the dumb electricity grid can be trans-formed into a smart, responsive and self-healing system—in short, an â€˜Energy’ Internet."|
First, utilities are looking for ways to produce and store power closer to points of consumption, to reduce the need to send so much power down ageing transmission lines. Second, these companies are looking at ways to move more power through existing transmission lines, and third, investigating sensor technology to monitor the grid in real time. Finally, utilities are evaluating control systems and power transmission hardware that can control the flow of power fast enough to avoid blackouts.
In this column we will look at ways to produce and store power closer to points of consumption. In next Part 2 of this column we will look at ways to move more power through the existing grid, and at sensors and at real-time control of the power grid.
Many believe that the best solution to an overloaded grid is not to build ever fatter pipes to supply ever more power from central power plants to distant consumers. A better answer may be "micropower"—a large number of small power sources located near to end-users, rather than a small number of large sources located far away.
Even the gurus at the Electric Power Research Institute, who rely on funding from utilities that run big power plants, agree that moving to a distributed model, in conjunction with a smarter grid, will reduce blackouts. ABB foresees the emergence of "microgrids" made up of all sorts of distributed generators, including fuel cells, wind, and solar power.
Among the commodities, electricity is almost unique because it cannot be stored efficiently. That means grid operators must match supply and demand at all times to prevent blackouts. But if energy could be widely stored on the grid in a distributed fashion, and released cheaply and efficiently when needed, it would transform the reliability and security of the grid.
Several energy-storage technologies now look quite promising: advanced batteries, flywheels (see Technically Speaking, CONTROL, Oct. 2003), and superconducting magnetic energy storage devices. But the most intriguing storage option involves hydrogen—which can be used as a medium to store energy from many different sources.
Hydrogen may power the cars of the future, but its most dramatic impact might be in power generation. That is because hydrogen could radically alter the economics of intermittent sources of green power. At the moment, much wind and solar power is wasted because the wind blows and the sun shines when the grid does not need power.
If that wasted energy was instead stored as hydrogen (produced by using electrical power to extract hydrogen from water), it could later be converted back to electricity in a fuel cell, to be sold when needed. Geoffrey Ballard of Canada's General Hydrogen, and the former head of Ballard, a leading fuel-cell-maker, sees hydrogen and electricity as so interchangeable on the power grid of the future that he calls the two together "hydricity."
Another benefit is that hydrogen could also be sold to allow passing fuel-cell-powered electric cars to refill their tanks. In time, those automobiles might themselves be plugged into the grid.
General Motors’ Tim Vail calculates that the power-generation capacity trapped under the hoods of the new cars sold in America each year is greater than all the country's nuclear, coal and gas power plants combined. Most cars are in use barely a tenth of the time. If even a few of these cars were plugged into the grid while parked, a "virtual utility" could tap the stationary vehicles generating power, employing them to convert hydrogen into electricity and selling it on to the grid for a tidy profit during peak hours.