Dec 29, 2006 (From the CalCars-News archive)
This prestigious publication is getting steadily greener. It's been covering PHEVs repeatedly, and if you want to This first article has been linked to from dozens of news stories and blogs in the past few days...searching for "How Plug-In Hybrids Will Save the Grid" in Google returns 10,700 links! Then in its end-of-year review, "The plug-in hybrid-vehicle era begins: is the second most important development, after cellulosic ethanol, before improved batteries and cheaper solar power. We include the text of both.
How Plug-In Hybrids Will Save the Grid
How Plug-In Hybrids Will Save the Grid
The use of vehicles that run on electricity could be a boon to the
ailing electrical grid.
By Kevin Bullis
MIT Technology Review - Cambridge,MA,USA
Small companies are already making kits that allow drivers to commute using electricity from the grid (stored in extra batteries shown here). When major automakers start making the kits, will charging these cars be too much for the grid to handle?
Major automakers and the Department of Energy are pouring money into research on plug-in hybrid vehicles. These cars promise to cut petroleum consumption by allowing commuters to drive to work using primarily electricity--stored on board in batteries--rather than gas. Although critics have warned that the vehicles could put too much pressure on an already strained electrical grid, experts are now arguing that rather than being a strain on the grid, plug-in hybrids may actually help prevent brownouts, cut the cost of electricity, and increase the use of renewable energy.
Plug-in hybrids, like today's hybrid cars, can run on either an electric motor or an internal combustion engine. But plug-ins have much larger battery packs and can be recharged by being plugged into the wall, making it possible to rely much more on the electric motor. Although a handful of companies sell conversion kits to change conventional hybrids into plug-ins, the kits add thousands of dollars to the cost of the car (see "Plug-In Hybrids Are on the Way"). This additional cost, which is primarily from the batteries, is one of the reasons the major automakers haven't yet mass produced such vehicles, although they are now developing them. GM, for example, recently committed to making a plug-in version of a Saturn SUV (see "GM's Plug-In Hybrid").
The concern is that plug-ins are not a good way to reduce gasoline consumption, because if they become popular, and millions of car owners recharged their cars at three in the afternoon on a hot day, it would crash the grid. But plug-in hybrids could actually help stabilize the grid if owners charged their cars at times of low demand, and if the vehicles could return excess energy to the grid when it's needed--say while parked in the company lot at work during peak demand.
Since utilities have built enough power plants to provide electricity when people are operating their air conditioners at full blast, they have excess generating capacity during off-peak hours. As a result, according to an upcoming report from the Pacific Northwestern National Laboratory (PNNL), a Department of Energy lab, there is enough excess generating capacity during the night and morning to allow more than 80 percent of today's vehicles to make the average daily commute solely using this electricity. If plug-in-hybrid or all-electric-car owners charge their vehicles at these times, the power needed for about 180 million cars could be provided simply by running these plants at full capacity.
This could be a boon to utilities, because they'd be able to sell more power without the added cost of building more plants. Ideally, this will translate into lower electricity prices, says Robert Pratt, a scientist at PNNL. It might also help utilities justify the added capital costs of building cleaner coal-burning plants, because they'll be able to recover their investment faster by "selling more electricity with the same set of iron, steel, and concrete," Pratt says.
Such a system could be further optimized by using smart chargers and other electronics. This system would include a charger that runs on a timer, charging cars only during off-peak hours. Researchers at PNNL are taking this a step further with smart chargers that use the Internet to gather information about electricity demand. Utilities could then temporarily turn off chargers in thousands of homes or businesses to keep the grid from crashing after a spike in demand.
The next step would be to add smart meters that would track electricity use in real time and allow utilities to charge more for power used during times of peak demand, and less at off-peak hours. Coupled with such a system, the PNNL smart charger could ensure that the plug-in batteries are charged only when the electricity is at its cheapest, saving consumers money.
But what many experts are excited about now is a concept called "vehicle-to-grid," often abbreviated V2G. In such a system, plug-in hybrids, rather than being merely an extra burden to the grid, become a much needed way for grid managers to balance the amount of energy generated at any given time to match the amount of energy being consumed. Millions of cars, each with several kilowatt hours of storage capacity, would act as an enormous buffer, taking on charge when the system temporarily generates too much power, and giving it back when there are short peaks in demand.
In a V2G system, the batteries of millions of plug-ins would be used as a buffer to even out supply and demand and to help keep the grid stable, says Karl Lewis, chief operating officer of GridPoint, a startup based in Washington, D.C., that has developed technology that could help make such a system work. In this kind of system, each vehicle would have its own IP address so that wherever it is plugged in, the cost of the energy it uses to recharge would be billed to the owner. With the right equipment, the car could also return energy to the grid, giving the owner credit. Mock-ups of such systems have already been tested by the National Renewable Energy Laboratory (NREL), in Golden, CO, and by a company called AC Propulsion, based in San Dimas, CA.
Plug-ins could also serve as backup sources of power. In extreme cases, such as a blackout from a hurricane, the cars could keep essential systems up and running in homes and businesses. Even in this case, when the batteries could be drawn down considerably, the owner could rely on the internal combustion engine in a plug-in hybrid for transportation.
As an added benefit, "if millions of these [plug-in hybrids] were produced, it would enable some of the renewable technologies to really take off," say Terry Penney, a technology manager for advanced vehicle technologies at NREL. The challenge of using a renewable source such as wind is that wind is intermittent, varying day by day and minute by minute. A network of plug-in hybrids could smooth out these fluctuations by storing extra energy and sending it to the grid when the wind dies down. Such a network would also improve the economics of wind power by making it possible to capture more of the excess power generated on windy days, says Willett Kempton, senior policy scientist in the Center for Energy and Environmental Policy at the University of Delaware.
Such systems are many years off, as it will take time to install the needed infrastructure. Once plug-in cars are widely available, however, they could help relieve some of the pressure on the grid today.
Thursday, December 28, 2006
The Year in Energy
By Kevin Bullis
Biowaste to ethanol could soon power cars. Converting a vehicle to run primarily on ethanol costs just a couple of hundred dollars. But ethanol won't make much of a dent in gas use as long as the source of ethanol in the United States remains corn grain, which requires a lot of energy and land in order to grow. A much better alternative is cellulosic materials such as wood chips and switchgrass, which are both cheap to grow and require fewer natural resources. (See "Biomass: Hope and Hype.") In an effort to reduce the processing costs of these materials, researchers are genetically engineering organisms that can devour grasses and waste biomass, digest the complex sugars, and then transform the resulting simple sugars into alcohol. (See "Better Biofuels" and "Redesigning Life to Make Ethanol.") Already, advances in parts of this process have led to planned cellulosic-ethanol plants. (See "Making Ethanol from Wood Chips.")
The plug-in hybrid-vehicle era begins. For years, hobbyists and a few companies have been adding bigger battery packs to hybrid vehicles, which have both battery power and an internal combustion engine, and plugging them into electrical outlets. This allows the cars, which typically rely on the electric power only for short bursts or to assist the onboard gasoline engine, to run on electricity alone for short trips. The idea of the "plug-in hybrid" has now caught the attention of government officials and researchers, who note that gas consumption would plummet if drivers could rely almost exclusively on electricity for average daily driving of about 33 miles. The gasoline engine would be available to boost performance and make it possible to use the car for long trips. Now the major car companies are taking notice and are finally developing plug-in hybrids. (See "GM's Plug-In Hybrid.") Meanwhile, researchers are beginning to anticipate benefits from plug-ins beyond gasoline conservation: millions of plug-in vehicles could serve as massive energy storage to stabilize the electric grid and make renewable energy sources more feasible. (See "How Plug-In Hybrids Will Save the Grid.") Battery costs still need to drop before such cars will approach the price of conventional hybrids or gas-only vehicles. But better batteries are already becoming available.
Massive recalls spark interest in better batteries. The safety-related recall of millions of lithium-ion laptop and cell-phone batteries made by Sony and Sharp put batteries in the spotlight this year. Just in time, a new type of lithium-ion battery that uses materials inherently much safer than those involved in the battery recall started appearing in professional power tools. In addition to being safer, the new batteries are more powerful, have longer useful lifetimes, and are potentially less expensive than those utilized in laptops and cell phones today. All of this could make them attractive for use in mass-produced plug-in hybrids. (See "More Powerful Hybrid Batteries.") Meanwhile, a number of materials-science advances promise to as much as double the storage capacity of batteries and make them more long-lived. (See "3M's Higher-Capacity Lithium-Ion Batteries" and "Making Electric Vehicles Practical.")
Cheaper solar power is on the horizon. Solar cells have a well-deserved reputation for being too expensive. But a steady drop in costs, along with high electricity prices and government subsidies around the world, have led to a boom in the solar market. And while advances in conventional silicon cells will continue to play a major role in continuing this boom, emerging technologies will also play an important role. A number of companies are developing efficient solar cells based on microscopically thin layers of semiconductor material; they're also developing fast, high-volume manufacturing methods that could cut costs. (See "Large-Scale, Cheap Solar Electricity.") Meanwhile, others are developing similarly inexpensive manufacturing for mirrors and lenses to concentrate sunlight, which reduces the amount of expensive photovoltaic material needed. The concentrators make it feasible to use ultra-high-efficiency (and expensive) solar cells originally developed for use in space. (See "Cheap, Superefficient Solar.") This month one manufacturer of such cells set a new record by producing cells that convert 40.7 percent of the energy in sunlight falling on them into electricity. At the same time, others are developing advanced solar cells that mimic photosynthesis or harness nanocrystals to make better cells. (See "New Solar Technologies Fueled by Hot Markets.")
Clean coal technologies get mixed up in politics. Coal will be a major source of electricity for a long time, especially in places such as China and the United States. That's because it's cheap. The problem is that burning coal emits huge amounts of carbon dioxide. While President Bush supports research into new technology that can reduce such emissions, the fact is that good technology, such as gasification, burning coal in pure oxygen, and methods for sequestering carbon dioxide, exists now that could make a big difference. (See "Simpler and Cheaper Clean Coal Technology" and "The Dirty Secret.") At this point, cleaning up coal is more in the hands of policymakers than in the hands of researchers.