Although plug-in electric vehicles (PEVs) haven’t been a runaway success, even the most cynical of industry watchers admit that their market penetration will likely be steady. PEV sales are falling short of the pace of 1 million vehicles the Obama administration had hoped would be on the road by 2014, but analyst group Pike Research projects that about 410,000 PEVs will be sold in the United States between 2011 and 2015, and that the 1 million mark will be achieved by 2018. Although the increase of PEVs will do many good things, it may not be so great for the national power grid as it exists today.

It is hard to measure how PEVs currently affect the grid, since their numbers are still low. A prototype green community in Austin, Texas, however, is giving researchers some insight into how a concentrated number of PEVs in an area might affect the grid. Mueller is a master-planned and mixed-use sustainable community constructed on green building principles. It uses smart meters and home management systems, and its residents are using PEVs. Once Mueller is complete, it will house as many as 13,000 residents on nearly 700 acres.

Mueller has offered researchers at Pecan Street, a research arm of the University of Texas at Austin, a look into the PEV use of its residents. They crafted a study that collected electricity-use data from PEV owners every 15 seconds to develop an overall picture of how Mueller residents charged their vehicles. They found that most of them typically plug in their PEVs between 3 p.m. and 8 p.m. — about the same time period where home electricity use spikes, as dwellers turn on air-conditioners, dishwasher, stoves, washers and dryers, computers and televisions. Fully charging a typical PEV takes about four hours.

Expecting Up Load

Utilities are becoming concerned about the energy load that a rise in PEVs would put on the grid. In addition to ordinary spikes in energy demand at the end of the day, greater use of PEVs might force energy suppliers to turn to “peak generation,” which is the firing up of supplemental facilities (often older and dirtier power plants) and resorting to the use of gas turbines and other secondary measures to generate energy. This could spike costs for utilities  — costs that would be passed on to customers — and mean dirtier power, Scientific American concluded in a recent article.

The U.S. Department of Energy has examined the potential conflict. A January 2011 report commissioned by the DOE and conducted by the National Energy Technology Laboratory noted that the high demands PEVs place on the grid might be an obstacle to growth for the EV industry and its manufacturers. The report concluded, however, that if critical grid and vehicle issues are resolved, PEVs may become more attractive to end-users and less of a concern for energy suppliers in terms of load balancing.

The DOE believes that the solution lies in so-called “opportunistic charging,” or “smart charging.” Using smart grid technologies, energy suppliers could create new approaches that would balance charging schedules, avoid harmful and costly spikes and offset existing peak demand. By using solutions that can help schedule and spread out vehicle charging times to off-peak hours and days, including pricing incentives that encourage PEV owners to charge their vehicles during hours of low demand, utilities could balance the grid load, keep costs down and avoid having to activate dirtier peak-generation resources.

Some EV technology manufacturers have been quick in recognizing the potential of smart charging for PEVs and are already producing solutions.

IBM, Pacific Gas and Electric and Honda are collaborating on a project to enable electric vehicles and the power grid to communicate with each other, reports the website Hybrid Cars. IBM’s cloud-based solution for utilities (in this case, PG&E) could carry data between an electric car’s onboard computer, its owner’s smart meter and the grid, allowing the system to create schedules to balance charging.

“The novel concept is basically taking the vehicle data — such as a battery’s state of charge — and grid data from PG&E to create an optimal charge schedule for the EV so we aren’t taxing the grid or inconveniencing the driver,” says Clay Luthy, IBM’s global distributed energy resource manager.

While a PEV owner might come home from work and plug in her car right away, she could instead choose to schedule her vehicle charging for between 2 a.m. and 6 a.m. She would wake up to a fully charged battery and see lower rates on her electricity bill, since she is charging when off-peak rates are in effect.

IBM is in the process of working with Honda engineers to integrate its cloud-based software with the automaker’s Fit electric vehicle. Preliminary tests of the smart charging system show promise; an effective solution could help boost the acceptance of PEVs among consumers and lower the fears of energy providers.

Looking for New Technological Solutions

Helping PEVs charge faster is another solution — one that GE has been working on. The company’s WattStation charger was designed to decrease the time needed to replenish a PEV battery. Coupled with smart grid technology, WattStation could potentially help utility companies manage the impact of electric vehicles on their grids.

Another solution may be new kinds of PEV batteries, the DOE report noted. These batteries can also use cloud-based communications to “talk” to utility companies.

“Batteries provide the majority of interaction between the vehicle and the grid, so their development will be pivotal to building a grid infrastructure that supports EV charging,” the report’s authors wrote.

Some EV proponents suggest that forward-thinking employers looking to attract and retain green-minded employees who drive electric cars should install charging stations for them at work. For starters, it would allow employees to charge their EVs during non-peak periods, such as mid-mornings. It might even be cost-effective for utility companies to help subsidize or offset the costs of employer-provided power for EVs: it would take some strain off the grid and allow utilities to remain within their emissions boundaries and avoid costly fines.

Yet more solutions include the development of renewable energy charging stations that use small wind turbines or

GE’s solar-powered charging station for PEVs, located at its facility in Plainville, Conn.

solar panels. Wind- or solar-based charging stations could be strategically added to take advantage of sunlight or wind to charge PEVs in neighborhoods, public parking facilities and office parks. Several solar-based charging stations are already in operation in some California cities, including Diamond Bar, Azusa and Santa Monica. In 2011, GE unveiled the EV Solar Carport at its facility in Plainville, Conn., using a series of its own EV Charging Station products.

One of the most novel solutions proposed uses smart grid technologies to network charging PEVs so that they may be used as mobile storage devices. Grid operators could essentially use the power stored in cars’ batteries when they need an extra boost of power, replacing it later when grid demand is lower. Called a “vehicle-to-grid (V2G)” program, it could turn a city’s EVs into a distributed storage resource that allows energy suppliers to effectively regulate demand.

While widespread PEV use may still be well into the future, it is not too early for forward-thinking manufacturers to begin developing usage solutions that help pave the way for EVs. If improperly managed, electric-vehicle charging demands could do more damage to the nation than good.

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