The Boulder Experiment
Interstate transmission could bring renewable power to consumers, but that solves just half the problem. Once the power arrives onsite, it must be used efficiently for the grid to thrive. On the local end, the difference between renewable energy and more conventional forms is variability: Clouds darken the skies above solar panels, and winds fluctuate even from minute to minute. The smart grid must allow customers to make the most of the energy when it arrives while taking back excess and saving for a rainy day. (We may also need to augment renewables with a steady source; see “New Tech Could Make Nuclear the Best Weapon Against Climate Change.”)
It all comes down to balancing supply and demand, says mechanical engineer Rob Pratt, who runs the smart grid program at the U.S. Department of Energy’s Pacific Northwest National Laboratory in Richland, Washington. “The grid has almost no storage, so it has to generate the power that’s being consumed almost instantaneously, inside of a minute,” he explains. Get too far behind and the grid goes black. “It’s just like your car stalling on a hill. The grid slows down fast, and if it slows down too much, it falls apart.”
The present mode of operation—essentially unchanged since the invention of power grids in the late 19th century—keeps blackouts at bay by measuring total consumer demand and throttling up and down on the supply of electricity from power stations as needed. It works, but it is a bad fit for renewable energy. Solar panels and wind turbines can stop supplying electricity at any time if the weather shifts. So even when the renewables are going strong, conventional power plants must always be at the ready to step in and carry the load.
Smart grids will do better by inverting the power system’s most basic rule of operation. Instead of adjusting power output in accordance with shifting demand, they will help consumers control their use of electricity, timing it to coincide with availability of the grid’s cleanest and cheapest power sources. “With a smart grid we can adjust the load to follow dips in the wind and the sun,” Pratt says.
This tail-wagging-the-dog scheme is approaching a critical test in Boulder, Colorado, where Minneapolis-based utility Xcel Energy is rolling out one of the first systemwide installations of a smart grid. The key goal: managing wind and solar resources not just through storage but also through technology-assisted consumer participation.
“Our customers don’t change their consumption when the wind quits blowing,” explains Mike Carlson, in charge of the smart grid strategy at Xcel. “So we need to build or procure backup resources to keep power level when the wind quits.” Getting Xcel’s customers engaged is what the smart grid experiment is all about, he notes. The key is giving customers cues when renewable energy is available and making it easy for them to change their consumption patterns accordingly. “Anecdotally, our customers are saying, ‘If you give me the tools, I’ll help you out when the wind quits blowing so you don’t have to keep the fossil fuels burning in the background,’” Carlson says.
The Smart Meter
By this summer, 25,000 families and businesses in Boulder should have the key tool they will need: a 21st-century upgrade to the humble electromagnetic meters measuring power consumption in basements across the country. Those old meters epitomize today’s power grids, where a steady but essentially blind flow of electricity and the occasional visit by a meter reader is all that links power plants and distribution systems to consumers. Xcel’s new smart meter, in contrast, belongs to the Twitter generation.
The smart meter will check in with the Xcel central office every few seconds via signals sent over the power line itself, creating a two-way digital conversation. Instantly the utility will know how much power a given customer is using, and perhaps even how much she plans to consume later.
In a couple of months, customers in Boulder with smart meters should be able to check their energy usage in real time. By early next year they should be able to check grid conditions and control usage over the Internet—for instance, reducing consumption while away from home by activating a vacation mode.
In this first implementation, the smart grid’s feedback mechanism is manual: Consumers must go online for an update on current grid conditions and then actively alter their use of power. For example, winds predicted to energize the nearly 1,100 megawatts of wind turbines on Xcel’s grid in eastern Colorado could be a cue to hold off on running the dishwasher until bedtime. “I don’t care when my dishes get washed,” Carlson says. “I just want them washed by tomorrow morning.”
Ultimately, Carlson says, the process will be automated so that computers make many of the power calls, controlling everything from pool pumps and refrigerators to air filtration systems according to changing grid conditions and the consumer’s preprogrammed preferences. All of these loads, connected to the system by wires or wireless gateways, can be turned off for a matter of minutes or hours without most customers’ ever even noticing.
The impact on the grid could be considerable. In 2007 Pratt’s team collaborated with IBM to equip 112 homes on Washington State’s Olympic Peninsula with a smart meter and wireless switches to control their thermostats and water heaters. The switches could be programmed to shut off when power demands on the grid (and hence electricity prices) peaked. The average homeowner shifted enough consumption to shrink his peak electricity use by 15 percent.
The effects could be even more dramatic for those Boulder-area residents who will be plugging cars into the smart grid conversation. Xcel hopes to convert up to 500 hybrid cars owned by the county, the city of Boulder, and the University of Colorado to plug-in hybrids by adding larger batteries that can be charged from the grid. Several, including the university chancellor’s Ford Escape, are already on the road. Like Carlson’s dishwasher, the hybrid vehicles will recharge when electricity is in low demand or when wind power is abundant.
The Boulder plug-ins can also intervene to help the grid. When a blistering summer afternoon has power lines straining to support a city’s worth of air conditioners, for example, a signal from the utility could ask the vehicles to give back some of their stored charge. “They can act as storage batteries for the grid, soaking up excess capacity,” Pratt says. “That will really help us out with the intermittency of renewables.” The chairman of the Federal Energy Regulatory Commission in Washington, Jon Wellinghoff, thinks plug-ins will be so beneficial to the grid that he has taken to calling them “cash-back hybrids.” Wellinghoff’s bet is that in short order utilities will be paying drivers to keep their mobile batteries plugged in to the grid rather than billing them for the power they consume.
The Road Map to the Future
Energy experts expect Obama’s stimulus money to crystallize political support for, and industry investment in, the next-generation grid. “The kick start to manufacturers of smart grid gear is going to be huge,” Pratt says. “We’re going to see a 20-year-plus transition turn into 10 years or less.” Carlson says Xcel will await hard numbers on the value of the smart grid, due in late 2010, before it expands beyond Boulder. But if the benefits match Xcel’s expectations, he says, look for smart grids to roll out nationwide within five years.
When it comes to the interstate expansion of power lines, the president’s stimulus and his renewable energy tax credits will accelerate a process already under way. The real challenge, according to Heyeck, is the hodgepodge of state and regional agencies whose overlapping authority and conflicting interests make interstate transmission planning a bureaucratic quagmire. State regulators call most of the shots as far as what gets built and who picks up the bill. Most are bound by state laws directing them to consider only the in-state benefits of new lines, so the broader benefits of the interstate grid could be ignored.
Lawsuits inevitably gum up the planning process further, since nobody wants a transmission tower in his backyard—even when it carries renewable energy. The Sierra Club, for example, is fighting a new line designed to bring solar, wind, and geothermal energy to San Diego. The line would bisect a national forest and (like any grid expansion) could also facilitate new deliveries of coal-fired electricity. Such hang-ups make even President Obama’s modest goal of adding 3,000 miles of new transmission lines look wishful.
What power companies really need, Heyeck says, is federal law creating a national process for designing an interstate grid, choosing a path for each leg, and allocating the construction and maintenance costs—preferably by billing consumers nationwide. With this kind of mandate, Heyeck vows that companies like AEP will get the job done. “Implement this support and tell us what projects to build,” he says, “and the private investment will come.”