The New Grid
Plugging into California’s clean-energy future
Take a look at the nearest light switch: is it up or down? The answer means more than you think. When you flip a switch — or run a washing machine, or plug in a space heater — you’re creating demand. And on a vast, interconnected electrical grid like California’s, supply must always meet demand. Otherwise, it’s lights out.
For more than a century we’ve taken the balancing act between supply and demand for granted, and for the most part, it’s worked. To accommodate sudden spikes in demand, engineers overbuilt the grid with excess slack, including wires that were thicker than they needed to be and standby fossil-fuel power plants that could fire up at any instant.
“Renewables integration into the grid poses a fundamentally new problem.”
Sascha von Meier
But today our 19th-century grid is being inundated by 21st-century innovations — among them the remote, large-scale solar and wind plants that are leading the state toward its clean-energy future. California has added nearly 2,800 megawatts of renewable energy capacity this year, almost equal to what it gained in the previous 13 years combined, the California Public Utilities Commission reports. In response to the Global Warming Solutions Act, or AB 32, the state has required its three largest utilities to acquire at least 33 percent of their power from renewable sources by 2020, up from the current 21 percent. Some analysts — and utilities — are aiming for well over 40 percent.
These new energy sources fluctuate according to nature’s whims and can’t be switched on at a moment’s notice. The more we rely on solar and wind to replace steady sources like fossil fuels, the less slack remains in the system, and the smaller the margin gets between peak supply and peak demand.
“Renewables integration into the grid poses a fundamentally new problem,” says Sascha von Meier, MA ’90, Ph.D. ’95, Energy and Resources Group, co-director of electric grid research for the California Institute for Energy and Environment. In various ways, von Meier says, the solar and wind energy that most of us in California are clamoring for — or already installing on our rooftops — is slowly transforming the system through which we deliver and receive power. And we’re not entirely sure what to do about it.
Many of the state’s top energy thinkers — including researchers in the Energy and Resources Group (ERG) and the College of Natural Resources, and their graduates now employed within the industry — are working to find an answer. In the end, it’s clear that no single approach will do; rather, a blend of public policies, technological innovations, energy-storage solutions, and increased flexibility on the demand side (that means you and me) will work together to help California reach its clean-energy goals and push well beyond them.
Renewable but unpredictable
Nancy Rader, MA ’92, ERG, has spent the bulk of her career championing renewable energy. From 1994 to 1998 she served as West Coast representative to the American Wind Energy Association, a Washington, D.C.–based lobbying group (in 1996, she was named its “Wind Industry Person of the Year”). For the last 12 years she has worked with the California Wind Energy Association, including 10 as its executive director. But even she doesn’t slough off the considerable challenge that large-scale wind power poses to California’s grid.
“We recognize that we’re an inconvenient energy source. Fossil fuels are incredibly convenient, except for the climate disruptions and other environmental issues they cause,” she says with a chuckle, as if to suggest that there’s no way fossil fuels’ benefits could outweigh their environmental impacts. But she acknowledges that fossil fuels provide reliable power. It’s there when we need it, capable of being fired up to accommodate peak demand, and on top of that, it’s pretty cheap.
For Rader, that’s just the beginning of the conversation. With integration of wind energy into the grid presenting a new set of problems, her job is to find solutions. She has plenty of ideas to help increase wind power’s reliability and reduce its cost. One of the biggest takes aim at a policy of the California Independent System Operator (CAISO) — an independent body that operates the state’s electrical grid — that requires power plant operators to schedule their production 38 hours in advance. Rader and the wind industry want that time frame reduced to as little as 15 minutes.
The reason is simple: wind-power operators can’t always accurately predict their output, which is dependent on temperatures, weather patterns, and storms, even an hour in advance. When predictions are off, problems arise — costly ones. “If you can’t predict what your resource is going to do, you have to have someone waiting to come online at a minute’s notice, which is expensive,” Rader explains. “So the more accurately you can predict wind, the less standby generation you need, which translates to lower cost.”
CAISO is considering making the move within the next year or two. The change would all but eliminate one of the bigger obstacles to integrating wind power into the grid, and could be an immediate boon to the industry in California.
Large-scale solar energy faces similar challenges, though to a different extent. With its day-on, night-off schedule, solar power is in one sense more predictable than wind. But wind power tends to ramp up and down gradually, while a massive 500-megawatt solar plant in the Mojave Desert can be nearly incapacitated by a passing cloud, then just as suddenly return to full production.
The bottom line is the same: it’s not enough for energy to come from a clean, renewable source; it also must be there when we need it. “We have to balance the grid from moment to moment,” Rader said. “It’s important that the system as a whole be planned to ensure stability.”
The California Public Utilities Commission (CPUC), which oversees the state’s investor-owned utilities, plays a key role in the new grid. CPUC energy advisor Michael Colvin, ’05, M.P.P. ’07, says it is the commission’s job to help California achieve its environmental and energy-policy goals of 33 percent renewables by 2020 “without a huge sticker shock.” In addition to enforcing standards for reliable service and reasonable rates from large-scale solar and wind farms, the CPUC is developing innovative standardized contracts to help small-scale providers plug in at the local level. Sara Kamins, M.S. ‘06, ERG, the lead CPUC advisor on renewable energy programs, said accomplishing the state’s goals involves aligning the business, environmental, technical, and policy pieces. “Designing the state’s renewable energy policies requires finding win-win solutions that consider the interests of a diverse network of stakeholders.”
Feeding rooftop solar into the grid
Many renewable-energy advocates promote solar panels, or photovoltaics, on rooftops and over parking lots as the gold standard in clean power. Rooftop panels not only sidestep the environmental impacts of remote solar plants and wind turbines, but also generate power closer to where it’s used, are less susceptible to large-scale fluctuations due to their distributed nature, and, in the case of the increasingly popular parking-lot panels, offer a valuable bonus: shade. But one point most advocates miss is that photovoltaics can toss a monkey wrench into the gears of a local energy grid.
“There’s a lot of interesting phenomena that are happening at that level due to rooftop solar that’s feeding power into the grid,” says von Meier, who is currently teaching a new course on electrical power systems at Berkeley. “One of the things we’re studying very carefully [is] the effects of distributed generation on the power quality and the management of distribution circuits.”
Preliminary research has shown that rooftop solar panels can degrade power quality in their immediate area. In some cases, upon reaching a certain saturation point — one that varies from neighborhood to neighborhood and is difficult to identify in advance — their interaction with outdated voltage regulation equipment may cause damaging power surges or dips in neighboring homes, possibly frying computers and other sensitive equipment.
“Ultimately, all we care about is making power in equal power out.”
The details can quickly become arcane for anyone who’s not an electrical engineer, but even experts don’t know quite what to expect as adoption of rooftop solar becomes more widespread, von Meier says. Some neighborhood circuits could be just fine, while others could experience significant issues; it varies on that small a scale. “There’s a lot of uncertainty and worry on the part of utilities that it may produce technical problems,” she says. “It’s very much a patchwork quilt, and no two circuits are the same.”
The first step in assessing the risk posed by rooftop solar is to gather more data. Utilities up and down the state are beginning to install devices on distribution circuits that record information about how much power is flowing and in which direction. Smart meters can serve a similar purpose. Before they were implemented across California over the past few years, utilities had so little information about local circuits that they didn’t know a neighborhood had lost power until irate customers called to complain; even then they couldn’t remotely pinpoint the source of the problem. Now smart meters, although controversial among some privacy and health advocates, are one component of an evolving “smart grid” that can provide real-time data on the flow of electricity through local circuits.
“You need to have a good understanding of what’s happening before you take action,” von Meier says. Once that’s accomplished, the next move toward ensuring reliability — the true gold standard for power within the industry — could be to install state-of-the-art voltage regulation devices on local circuits, which can smooth out the peaks and valleys resulting from intermittent sunshine feeding rooftop panels.
Such localized disruptions are nothing compared to the risk of remote solar and wind plants potentially triggering blackouts or brownouts due to unexpected fluctuations in output. “What happens when 30 percent of our power comes from solar or wind, and a cloud goes over or it doesn’t blow?” asks Tim Woodward, ’82, managing director for Nth Power, a San Francisco–based energy-technology venture capital firm. “How do we deal with that?”
The most commonly prescribed solution is massive batteries that can store and distribute energy as needed, increasing the buffer between supply and demand. Yet affordable, cost-effective batteries remain at least five to ten years away, says Woodward. Until we experience an actual grid failure or similar event triggered by renewables, he predicts, a market for the batteries is unlikely to materialize.
In the near term, a complementary — and increasingly popular — approach is to focus on accommodating variability at the other end of the system: inside the homes and businesses where we actually consume the power. Duncan Callaway, an assistant professor of energy and resources, is a believer. He spends much of his time studying what’s known as demand response, or load flexibility, in which users adjust their demand according to supply.
“Ultimately, all we care about is making power in equal power out,” he says. “If you can accomplish that by encouraging electricity consumption at different times, you can do it without having to build more storage infrastructure.” Manual demand response — where utilities phone their customers and ask them to please ease back on the air conditioning — has been around for decades, but the new wave is automated, continuous, and sufficiently seamless that most people won’t even notice. It works by sending wireless signals to smart appliances and other devices — again with the help of smart meters — about how much energy to use within a set of consumer-determined performance parameters that could potentially be programmed, like a thermostat or light timer.
The aim isn’t just to use less energy, Callaway says, but to use it at the right times. Such a fine-toothed approach, which will require both technological advances and regulatory work to become feasible, would help the grid adapt to the uneven profile of renewables on an ongoing basis, as well as avoid outages during peak events.
Sometimes energy draw can even be nudged upward to account for renewables. In 2010, a storm caused a field of wind turbines in Oregon’s Columbia River Gorge to nearly overwhelm the grid with power, prompting local agencies to pilot a new method of storing excess electricity: remotely cranking up the dial on special water and space heaters inside participating customers’ homes.
Information is power
Successfully adopting both batteries and demand response will take an intimate understanding of how California’s grid functions on a real-time basis. That’s precisely the goal of a powerful new model out of UC Berkeley, developed first for California by Matthias Fripp, M.S. ’03, Ph.D. ’08, ERG, while completing his dissertation and later expanded to all of western North America and then overseas by Dan Kammen and his students. Kammen is the director of the Renewable and Appropriate Energy Laboratory, an ERG and Goldman School of Public Policy professor who was Fripp’s faculty advisor.
California’s Energy Commission and Air Resources Board have already begun to employ the model to calculate carbon emissions caused by electricity generation, Kammen says. But it can also be used to solve for both cost and reliability, especially in regard to the intermittent output of most renewables.
“On the supply side for wind and solar, we’re incredibly detailed,” Kammen says. The model integrates current meteorological data and will permit electricity infrastructure and operational issues to be integrated with data on current and forecasted climate change, which allows a diverse power supply pool to be managed with far more sophistication than it is today, Kammen says. “The energy world of the future will look more like a real-time eBay. Ultimately your house, car, and the local industry can all be seen as buyers and sellers of energy, ideally valued highly on their cleanliness.”
In other words, California is on the brink of experiencing radical changes not only to how electricity is generated and consumed, but also to how it’s distributed. Some of the technology needed to make that happen already exists; some of it still needs to be developed. Yet with the world’s eighth-largest economy this committed to the cause, the biggest question left to answer isn’t if, but when.