A Charge Unanswered is a Charge Believed: The real economics of charging vs fueling

June 15, 2017 |

This short post on first-gen biofuels vs solar went viral on LinkedIn last week — thousands of likes, shares went bananas, it made a deep impression across the internet.

Say 1 acre of corn ethanol produces 500 gallons, one acre of solar, 200kW, avg. US insolation on tracker produces 300,000kwh per year. Electric cars use .325kwh/mile so Solar powers 71 cars per acre per year assuming 12,000 miles driven and ethanol powers 1. We should replant all ethanol acres with solar.

71 to one?

I know, you’re about to ask me “where is electric transmission & distribution loss?”, “why isn’t this using the solar insolation rates for Corn Country?”, “why is this comparing kw/h for small EV sedans to mileage for big fuel-powered SUVs” and “why are we comparing solar vs ethanol instead of solar vs petroleum?”

And you’re gearing up to say, “wait a minute, those ethanol acres produce distillers grains, CO2,  and corn oil — what are the cows supposed to eat? Are we all supposed to drink flat sodas? What do we use in situations that call for vegetable oil?

Whoa Nelly. We’ll get to all that. But here’s the thing. It’s not completely crazy math, which may explain why the internet went wild. There’s enough unsaid to leave a false and dangerous impression, and to quote the old Washington saying, “a charge unanswered is a charge believed”.

So let’s get into the charge, and the re-charge, and the re-fuel, and the economics, and the hard data.

The Hard Data: solar vs corn ethanol

Yes, transmission losses, solar insolation where corn grows, and comparing small EVs to large fuel-powered cars, these are omissions by our gone-viral commentator. Let’s correct those quickly, 30% loss in transmission, 30% loss for the reduced solar insolation in Corn Country, and another 60% to even up the fuel economy comparison because economy-sized sedans don’t get 24 miles to the gallon.

But even so, the differential is like 36 cars per acre for solar compared to 2 cars for ethanol. The difference has been exaggerated, but it’s still stark.

So, we need to consider why we are investing in a lower-efficiency energy system for transport, in the first place.  And, it does go back to the economics. just not those economics.

If Only

Here’s your starting point. If civilization had been  invented this morning, we might well have built a 100% electric small sedan fleet and stable electric grids, instead of using the gasoline-powered internal combustion engine.

But come to think of it, if civilization was invented this morning, people would speak one language, one dialect.

We’d all drive on the same side of the road. We would have built computers that didn’t have Y2K problems. We would have one universal power outlet, one global voltage for home use, one television display system, one remote for the TV. The Ten Commandments would have come on a disk, no freeway would have to be widened, asbestos would have been avoided as a building material, and no one would have given so much spectrum to radio and TV, it would have gone to mobile.

The Big Headache

Welcome to the Big Headache of Western Civ, which is the problem of Existing Infrastructure.

In the case of ethanol (and, ahem, gasoline) vs. solar-powered EVs, you really could generate all the power for America’s passenger car fleet off about 40 million acres of land. That’s the land area of Washington state. But it’s not going to happen any time soon, for the same reason that the world will not wake up tomorrow speaking melodic, yet easy-to-learn Swahili.

The 5 Whoops

Here are the 5 Reasons We have to Go Slowly on Transformation of the economy, and why bio has a strong role in the transformation that will take place.

1. The world has a billion existing vehicles and the US has more than 250 million, and they fuel up (except for a handful of electrics) at conventional fueling stations.

2. Depending on vehicle size there may be a) some very good electric alternatives, b)  trade-offs that are very tough (think heavy-duty), or c) alternatives that will not appear for decades and decades (think marine and aviation). So it is not just a question of efficient fuel sourcing, it is about people choosing vehicles that are fit for purpose.

3. Capital costs for energy transformation are huge. Installing solar on something like 40 million acres isn’t just about PV costs (though, we’re talking about billions and billions of dollars, even at $1/watt).  There are serious transmission & distribution issues balancing load and demand and because the US operates three geographically distinct grids, it’s not as simple as producing power here and moving it there. And, there are serious costs of to establish charging stations to support 10 percent of road use (vs 1 percent today, most of it in California).

4. To make the obvious point that someone at Nissan is probably impatient for us to relate, ethanol happens to be one of the most efficient pathways to serving onboard energy to an electric motor. Rather than storing energy in a battery, you can store it in ethanol, and deliver electricity via a fuel cell. You can learn more about that vehicle and its 600km range right here. And if you think that the ideal use of solar is to help make high-density liquid fuels, read here.

5. Ethanol is a fuel oxygenate and source of octane, and you need both of those for conventional vehicles. There are alternatives to ethanol, but E0 (ethanol-free, straight gasoline) costs 18 percent more (e85prices.com has the hard data), and a sudden transformation (at current prices) would cost the economy around $73 billion per year.

EV vs biofuels vehicle cost economics

Let’s look beyond the national economy and get down to individual vehicle ownership.

1. Consider the problem of the Mitsubishi Outlander PHEV – the world’s best-selling electric hybrid that happens to be a larger vehicle. Looking at the US market, the base model (fuel-powered version) costs $24,000, has a range of 450 miles, and refuels in 1.3 minutes.

By contrast, the PHEV version costs $42,000, the range is 32 miles all-electric, recharges in 3.5 hours, and is missing the third row of seats. Ouch.

2. Here’s the hard data on that vehicle — if you amortize the vehicle cost over 10 years.

Per-year, in all-electric mode, you’ll pay:

$4200 for the vehicle ($3620 if we count the electric vehicle tax credit)
$2695 for retail recharges or $637 at home
Monthly cost (excluding maintenance & repair), $354-$574

Per year, in all-fuel mode, you’ll pay:

$2400 for the vehicle
$1120 for the re-fuels
Monthly cost (excluding maintenance & repair), $293

Yes, we are comparing SUVs, but the comparison holds up in any class of vehicle. It’s not a pretty fact that conventional vehicles cost less, but it is a hard fact that will shape how we transform and de-carbonize the economy.

EV vs biofuels vehicle carbon economics

There’s a perception out there that EVs have no emissions, and that’s because the energy conversion happened elsewhere, the power is an energy carrier. But the Mitsubishi Outlander has a carbon intensity rating of 41 — far better than gasoline at 100, but biodiesel rates around 11 and cellulosic ethanol rates between 20-40 depending on the source. So, let’s consider that in our de-carbonization thinking

EVs will be green when the grid is green. In the case of solar, it’s an outstanding case of carbon reduction — it’s not zero (after all, there’s carbon intensity in making a solar panel), but it is de minimis.

But then, so are the very best of biofuels, if we are going to compare “best on best”.

The very best biofuels, in terms of carbon intensity — are carbon negative. These are usually systems that produce a carbon-sequestering soil biochar as one of the products from the process, so you have a low-carbon fuel easily offset by the biochar.

The Bottom Line

Straight-up, best on best for energy efficiency. Solar EV rocks it every time.

Straight-up, best on best for cost. Biofuels rule.

Straight-up, best on best for carbon. Carbon-negative biofuels win the day.

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