One of the key concerns with the growth of electric vehicles is whether the United States electric grid will be able to manage the growth of vehicles plugged in. This is particularly a concern in areas that have experienced rolling brown and black outs during summer months when the air conditioning is cranking on high. Add to this, potential fresh concerns over nuclear power plant safety and one of the first questions I often get asked about plug-in electric vehicles (PEVs) is whether our grid can take the additional draw from recharging all these vehicle batteries.
This is not a simple question to answer. Obviously, there is a component of consumer behavior. How will consumers recharge the vehicles? Will they all plug in at the same time? Electricity costs in the select areas with time of use pricing certainly steer most consumers to charge at off-peak times and many studies show that consumers who charge at home do just fine. However, many consumers will likely have some concerns about having enough mileage to get home (particularly initially) and may be inclined to charge during the day. So, smart grids and smart overnight charging are being developed to help ensure that when PEV charging is happening it isn’t bringing down the whole town.
But all of this raises the question of where do we need to be most concerned about this? In Pike Research’s recent “Electric Vehicles Geographic Forecasts” report, I attempted to address this by answering two key questions: Where will the vehicles be? And, how much power will they draw?
In figuring out where the vehicles will be, I examined data from manufacturers, consumer survey data, census demographic, and household data to forecast that New York City, Los Angeles, San Francisco, San Diego, and Chicago will be the MSA’s with the largest numbers of PEVs by 2017.
But this is only half the story. Using this forecast data and overlaying it with the electric utility service areas, I generated a forecast for the utility service areas. By using industry averages for PHEVs and BEVs of 14 kWh and 22 kWh batteries with recharge times of 4.25 hours and 8 hours, respectively, I calculated the draw for specific electric utility service areas. This is purely a hypothetical maximum draw, which assumes everyone plugs in and charges their vehicles from zero to full all at the same time – all of which I admit is highly unlikely.
By 2017, Southern California Edison and Pacific Gas & Electric are the two electric utilities facing the greatest exposure with 498.6 MW and 466.5 MW potential electricity demands, respectively. However, when measured as a percentage of generating capacity (2009 figures), Pacific Gas & Electric is the most likely to find themselves in a crisis first, since 466.5 MW accounts for about 6 percent of their total generating capacity. The electric utility for the largest single PEV MSA, Consolidated Edison, has a potential draw of 241.9 MW. Since Consolidated Edison buys wholesale power instead of generating their own (in theory) they can just purchase additional power to make up for the extra demand.
Since this measure of total potential draw is a worst case scenario and highly unlikely, this tells me that PEV energy draws, even in California, are likely to be easily handled in the near-term. However, the total cumulative number of PEVs in the United States by 2017 is 1.5 million vehicles. That’s a pretty small number. So, will electric utilities be prepared for twice this number of vehicles by 2025? And don’t forget that electricity demands from non-vehicle sources are growing too. That seems a little less certain, but one thing is certain, planning for more generation capacity needs to start now, if it’s going to be online in time.
Article by Dave Hurst