The Must-Have, $10,000 Add-on for Your Chevy Volt

If there's one thing I've made fun of in my time here, it's the Chevy Volt from Glorious People's Automotive Collective Number 1.  To use a quote from here:

"So while it will work for many commuters (as would an electric golf cart), it still seems to be a $40,000 car with all the room and comfort of a $15,000 car." 

I've also poked fun at another over-hyped technology, the smart-grid (see It's not about you) although I'll be the first to say I haven't poked enough fun at smart grid. 

According to an industry magazine, Energy Efficiency & Technology, these two technologies seem to have combined to produce the must-have accessory for the Volt.  "Must have" in the sense that you're going to be forced to buy it and billed for it by your power company: a new distribution transformer.  The reason is the way electricity is distributed.  AC is used in most places on the power grid because it's the easiest way to move electricity around. 

The problem is described in the editorial of the January/February issue of EE&T (digital edition, p.6).  Prof. Saifur Rahman of Virginia Tech has analyzed this problem and is quoted throughout the editorial.  The higher voltage going into the neighborhood is dropped to the 120 that goes to your house (in the US, of course) by these distribution transformers.  There is usually one of these to every five houses, and it's rated for 25 kVA (kilo Volt*Amps not kW - a topic for another day).  They budget 6kVA for the average house and you can quickly see that 5 houses makes 30 kVa not 25, but they rationalize that by saying it's not likely everyone will be using the full 6 kVA at the same time.  And they're usually right - it's by the same logic that the phone companies have a dedicated pair of wires for only about 10% of the houses they serve. 

Enter the electric cars like the Glorious Volt (what's that smell?) , Nissan Leaf or the Tesla.  As the market share grows for these cars, it's not unlikely that five owners could arrive home at the same time and plug in their chargers.  The chargers for these smaller electric cars might be 40A, the same as a central air conditioner load.  That smell might be a burning distribution transformer.  When the utility comes around to install the transformer, who gets the bill?  Probably the last guy who plugged in his car.

"I know a Tesla owner in California who had to pay $10,000 to have his transformer upgraded", says Rahman.  "That's a bigger EV and its charger draws 100A.  But he'd just shelled out over $100,000 on his Tesla, so spending another $10,000 was not a big deal for him."

Now think of this problem in terms of the solar panel project.  First, it gives us a reasonable  estimate for a home power - 6 kVA, not the 20 I was talking about.  Second, think of adding a 120V charger at 100 Amps!   At 12V that's 1000A, and if that doesn't make your head spin, I don't know what will. Even the 40A charger for the smaller cars turns into 400A at 12V; that's a crazy amount of current.  That's the kind of current you need to run in copper wires bigger than your thumb. 

What's the smart grid connection?   First, the main point in that post "It's Not About You" was that a smart grid can't generate new electricity, it can only ship it around to places where more is needed from places that have excess capacity.  If nobody has excess capacity because everyone is plugging in cars, nobody gets extra power.  Every penny we spend on smart grid is a penny not spent on power generation (which is opposed by the anti-progress crowd). Second, to quote that post:

Another thing to control is an outlet you might plug your electric car or hybrid into for recharging.  The power that you would get out of gasoline has to come from somewhere; in this case, you've moved your expense from the gas station to the electric company.  These chargers can consume large amounts of current in their fast-charge mode.  In turn, what the electric company wants to do is to not allow your charger to run during the early evening when TVs, dishwashers and other appliances are on.  They want to turn on your charger in the early morning hours; if everyone in your neighborhood had an electric car, say, they might time stagger the charging time for users to minimize the load on a transformer.   

If they try to charge everyone's car in the midnight to 6AM block, what if you can't live with that?  What if you work then, and need to charge your car during the prime time for power use?  

Look, if you want a Volt or a Leaf, go for it.  Buy your $10,000 transformer, or your $50,000 worth of solar panels.  But with each of these cars being subsidized by the rest of us to the tune of about a quarter of a million dollars, don't come looking to me to pay for your toy.  I'd rather spend my money on more power generation.