The one question that must be answered

Life is full of questions, from “When is supper ready?” to “How will I get to work?” The one question that isn‘t asked often enough deals with the energy challenges brought about by today‘s volatile energy markets and the solutions being proposed to address them: “Where will the energy come from?”

The plug-in electric vehicle or PEV is an example of a technology being proposed without asking—and, more importantly, answering—the question, in this case “Where will the electricity come from for these vehicles?” Instead, proponents of PEVs focus on the fact that electric vehicles are quiet and have no emissions. Others point to the speeds that some electric sports cars can achieve and the distances that new battery technologies may allow.

To be fair, proponents are asked the question occasionally; however, the response is typically vague, listing electrical generation capacity such as wind, solar, hydroelectric, and perhaps nuclear, or that the PEV will be charged overnight.

The energy required to move any vehicle, whether electric, gasoline, or diesel, is the same, assuming the same weight and style of vehicle. Although driving habits play a part, it is the efficiency of the engine—converting the fuel to mechanical energy—that ultimately determines the amount of energy consumed; a gasoline engine is about 28% efficient whereas an electric motor can exceed 90% efficiency. For example, an electric version of a gasoline-powered automobile that consumes 2,000 litres per year would require about 6,000 kilowatt-hours of electricity.

PEVs, like gasoline-power automobiles, must carry their energy with them. In a PEV, the electricity is stored in batteries. Since no battery is 100% efficient, a portion of the electricity stored in the battery will be lost and not be available for moving the vehicle. The less efficient the battery, the more electricity required to move the vehicle. For example, a 70% efficient battery would require about 8,600 kWh of electricity to be stored to produce 6,000 kWh, whereas a 90% efficient battery would only require 6,700 kWh.

At a dollar-a-litre, driving a gasoline-powered vehicle that consumes 2,000 litres of gasoline per year would cost about $2,000 for gasoline. On the other hand, at $0.15 a kilowatt-hour for electricity, driving a PEV would cost between $1,000 and $1,300 per year. With price differentials like these, the economics of the PEV suddenly become very attractive.

If a small number of PEVs appeared in a jurisdiction, the impact on the electrical system would probably be minimal; however, when the number of PEVs makes up a large portion of the vehicle fleet, the impact will be significant. For example, a recent study from the University of California at Berkeley suggested that by 2030, 60% of all vehicles on the road would be PEVs. If 60% of the gasoline and diesel automobiles that exist today in Atlantic Canada were replaced by PEVs, the total electrical demand would be somewhere between 7,000 and 9,000 gigawatt-hours (a gigawatt-hour is equivalent to one million kilowatt-hours), depending upon the efficiency of the batteries. To put these numbers into context, Nova Scotia Power produces about 12,000 GWh of electricity a year—meaning that over half to three-quarters of NSP’s output would be devoted to electricity for PEVs.

Clearly, before embarking on a large scale adoption of PEVs, the question “Where will the electricity come from for these vehicles?” must be answered.

One answer often put forward is wind. To obtain 9,000 gigawatt-hours of electricity a year about 3,500 one-megawatt turbines would be required. At $1 million a turbine, the infrastructure costs would be about $3.5 billion—a significant amount, but often presented as an acceptable price to pay since wind does not rely on insecure and environmentally damaging fuel sources such as coal. However, whenever a PEV needs to charge its batteries, it must be connected to the grid when the wind is blowing—any PEV not connected to the grid when the wind is blowing would not be able to take advantage of this energy source as electricity must be used at the time it is generated. On some occasions, there may be wind, but the amount of electricity being generated may not be sufficient to satisfy the charging requirements of the PEVs connected to the grid. In other words, even with 3,500 wind turbines, plugging-in wouldn’t necessarily result in a charge from the wind.

Another source of electricity, often promoted in Atlantic Canada, will be the Lower Churchill hydroelectric project in Labrador when it is completed. In theory, it could generate about 25,000 gigawatt-hours annually, meaning that the 7,000 to 9,000 gigawatt-hours needed for PEVs could easily be met and, unlike wind, charging could take place at any time. However, there is no guarantee that all the electricity from the Lower Churchill will be available to Atlantic Canada—just about every jurisdiction from Rhode Island to Ontario want some (or all) of the electricity it will produce because it is one of the few remaining secure and renewable sources of electricity in North America. This will probably mean that PEV owners will be able to charge their vehicles with electricity from the Lower Churchill, but the price will be determined by consumers outside the region.

Other proponents of PEVs point to the fact that during the overnight hours, most utilities continue to run facilities that cannot be easily restarted (typically large coal and nuclear plants), producing what is referred to as baseload electricity. If it is being produced anyway, so the thinking goes, why not use it to charge PEVs? The most significant concern with respect to charging during the overnight hours (11pm to 7am) with baseload electricity is that the demand from the PEVs may well exceed the available baseload, requiring additional capacity to be found. Meeting the annual 9,000 GWh requirement of PEVs during the overnight hours only would require an overnight baseload capacity of about 3,100 MW (the total generating capacity of NB Power’s Genco is 3,300 MW). If PEVs force utilities to generate more electricity from expensive, non-baseload sources of energy (such as natural gas and oil) to meet the demand, the overall cost of electricity will increase.

If widespread adoption of PEVs occurs before there are adequate answers to the question “Where will the electricity come from for these vehicles?” we may find ourselves asking other questions, such as “Can I cook my dinner while my neighbours charge their PEVs?”

Larry Hughes
Atlantic Construction and Transportation Journal, August 2009