Future grid: energy and transport September 16, 2014Posted by Maury Markowitz in power grid.
Tags: electric cars, power grid, solar power, wind power
I was watching the fairly silly Extant last night and saw a bit of tech that caught my eye; it was a burner cell-phone powered by a chemical reaction you started by twisting it like a glo-stick. It’s a little throwaway prop that I just love.
The reason I bring this up is that they also assume every car is electric. Nothing new there, but in this case they use an actual car instead of a made-for-TV model. Lots of Teslas and BMW i3’s.
And that got me thinking. What sort of overall effect is there on the grid if everyone starts driving electric? I know that electric cars use less power overall, but what sort of effect does that have on the big picture?
Well unless I’m doing the math seriously wrong, it looks like the answer is “bring it on!”
The problem is…
In case you’ve never seen it before, here’s a useful bit of infographics you might be interested in. It shows every single bit of energy that flows into and out of the USA. I’d love to show a similar graphic for Canada, but so far I haven’t found one. So here we go…
I hope everyone can read that OK. If you’re curious, a Quadrillion BTUs, or “quad“, is the standard way of measuring really big amounts of energy. If you convert that to electrical terms, a quad is 293 trillion kWh. That’s one quad, the US burns 98 of those a year. Yes, it’s a lot.
For the rest of this article I want to focus on the figure in the lower right. Transportation uses up about 27 quads, a little more than a quarter of all energy in the US. But what transportation? Cars? Trucks? Airplanes? We need more detail.
Luckily the same EIA web site has a fantastic tool for generating these sorts of things. We can’t get exactly what we need because they don’t break down gas, diesel, heating oil etc. All I can get is this graph of everything vs gasoline:
So we’re looking at maybe 9 quads of gasoline a year. And now we have pretty much everything we need to know.
What the future holds
I’m going purely what-if here… I’m not trying to predict the future, simply show you what happens if certain things change in certain ways. So we may as well go all in…
What happens if every car switches to a plug-in-hybrid in the next 15 years?
I certainly don’t expect that to happen, but I do strongly suspect the equivalent outcome will be close to the truth. That is, some cars will go PHEV, some will go all-electric, and others will stay all-gas, and the net effect is the same as if everyone went PHEV. As I said, I’m not looking for exact outcomes here, so feel free to come up with your own assumptions and plug them into the basic math that follows.
Ok, as I noted in my earlier article on wells-to-wheels, going PHEV will basically double the effective gas milage. In this case we’re assuming we’re going to also move from gas to electricity for much of the milage, so the gas burned will not go down by 50%, but more like 80%. So for argument’s sake, let’s say that we go from 9 quads of gas to 1.
Now you might think that we’ve simply moved that 9 quads from gasoline to 1 quad of gas and 8 quads of something else, but that’s not the case. When running on electricity, the car gets around 80 to 100 effective mpg, about triple what it would get running on gas. So we don’t need to make up 8 quads of something else, it’s more like 3.
Let’s sanity check that number.
The number of miles being driven is slumping, especially if you calculate it as a percentage of population. Right now it’s flatlined at around 3 trillion miles a year.
If we assume the Tesla S is typical of most electrics (it’s a good conservative estimate, most PHEVs are better), we get 38 kWh/100 mi. Every prediction I’ve read says that something like 80% of all trips in PHEVs will be electric, so that means we’re talking about 2.5 trillion of those 3 trillion miles. So if we have 38 kWh/100 miles and we have 2.5 trillion miles, that’s 950 billion kWh of electricity. So a quick trip to any handy online unit calculator, and we find that we need about 3.2 quads.
So even though we used a totally different methodology to come up with the number, the end result comes out the same, we need around 3 quads of electricity to power the car fleet of the US for 80% of all their trips.
Where we do we get it?
Ok, so we need to make up 3 quads of new electricity. Where are we going to get that? Well here comes the coup de grâce.
Back to the original EIA report. On page 5 you’ll find a table of total energy generation of all sorts in the US. Let’s consider one number for the last ten years: in 2003 wind turbines produced 0.113 quads, and by the end of 2013 that was up to 1.6. So in ten years we installed more than 1.5 quads of wind power.
But look a little closer; that number is accelerating. If you look at the two years from 2011 to 2013 that increase was 0.427 quads, or about 0.21 quads a year. Even if it stops accelerating and we just install at the current rate (which is extremely conservative due to market factors), that means over the next 15 years we should expect to install… 3 quads.
Now I want you to think about this – what is the #1 complaint that you hear about wind power? That’s its not there when you need it, and that we’d have to install all sorts of batteries to make use of it all.
What the future looks like
So the reason I started with the big picture is to show you what happens to it. Basically all that happens is that the transportation arrow in the lower left drops to about 2/3rds what it is today, and to offset this the renewables part in the middle grows a little bit.
It’s totally doable, tech wise. Whether or not we can figure out how to get people to buy PEHs is another matter, because it’s clear people would rather get a useless $5000 sat-nav upgrade than save thousands on gas costs, but that’s always been the case.
A lot seems to depend on the political will to stay the course with the current CAFE standards. Right now they are set to dramatically improve fleet milage, to the amount I’m using in this article, but whether or not future administrations will keep that going is anyone’s guess.
In fact, I think it’s easier to predict that we’ll have twist-to-power phones than whether or not we’ll have 50 mpg cars.