EVs are going to blow out the grid!

by Ernie Hernandez on March 12, 2012

One of only many EV myths

Many of us have heard the argument before – “Once all of those electric cars are running around they’re going to blow out the grid!” If you allow us a few minutes, we will hopefully provide you with a nice counter argument.

If you are an electric vehicle (EV) owner, by now you have likely discovered that the majority of charging occurs while you sleep. In fact, one of the biggest complaints of non-EV owners is that they don’t wish to wait around for hours for their car to charge. The reality of it is more like this – if you are waiting around hours for your EV to charge, you probably shouldn’t have bought or leased your EV in the first place.

One of our primary arguments about EV ownership is this – an electric car is a tool designed for a specific situation. Should you happen to fit into that situation, it is an amazingly efficient vehicle that offers many benefits – comfort, convenience, and a pleasurable driving experience. Oh, and the not so minor benefit of not contributing to the environmental pollution hanging around every major (and some not so major) population area in the world today. But if you absolutely must drive more than 70 miles or so daily, you might want to rethink your decision to acquire an EV unless you are confident that you can charge your EV while you work.

“Aha”, says your friend. “See! Then you will be adding to an already overloaded grid during the day!”

First – the grid is not already overloaded. In the United States brownouts (reduced voltage supply) or rolling blackouts (grid by grid removal of power) occurs in very rare circumstances. The most typical circumstance is during summer months with abnormally high air conditioning use. Ask your friend when the last time was that he experienced either of these occurrences. It is quite possible that he never has. These scheduled events are different than power loss due to accidental mechanical or electrical disruption to the power supply distribution system which is a random and unpredictable occurrence.

So a relatively small percentage of EVs may be charged at work, typically using 120-volt power. When plugged in and charging, a LEAF will draw roughly 1,200 watts of power. By comparison, if you dry your hair in the morning after your shower, you quite possible use an electric hair dryer. As of this writing, one of the most popular hair dryers (according to Amazon.com) is rated at 1,875 watts. Granted, you won’t be drying your hair all day (hopefully), but between 6AM and 8AM in households all over the country, many of these devices are in use simultaneously without any harm of taking out our grid.

But the real point here is that most of our charging occurs at night. In fact, to encourage charging your EV at night, many utilities will offer what is known as time of use rates. These rates will be broken down by time of day and called something like “Peak”, “Off-Peak” and ‘Super Off-Peak”. For instance, San Diego Gas & Electric (SDG&E) offers Super Off Peak from midnight to 5AM, On Peak from noon to 8PM, and everything else is Off Peak. The LEAF (and other EVs) offer an onboard charge timer, so you don’t need to wait until midnight to plug in. When you are done driving for the day, plug in and have your timer set to start charging at midnight. Plugging in takes all of 30 seconds or so. Midnight to 5AM is called Super Off Peak because nobody is using electricity then. It will take years before we will get to the point of EV adoption getting to the point of concern about crashing the grid. And by then, the utilities and car companies will have learned much about charge patterns, timing and duration from studying all of us early adopters, and may refine Super Off Peak rates by grid to rotate the times that timers will be programmed to click on. In other words, Super Off Peak for grid one might be midnight to 5AM while Super Off Peak for grid 14 might be 3AM to 8AM. This could serve to even out demand, as many times, the car will have recharged its daily use in only an hour or two.

EVs have a long way to go before our electricity demand will be a concern to the grid. And when you think about it, that’s not really a bad concern to have.

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