What is the true energy fallacy?

Some say that we will need a lot less energy when we go with renewables, but they are forgetting about Sadi Carnot. We will need the same amount of useful energy.

Sadi Carnot figured this out two hundred years ago.

I recently travelled to Detroit for a modern architecture tour, and upon returning, I immediately got in the car so Kelly could drive us up north to our cabin/cottage, only to find that my boat isn’t running (we are water access) and my pumps aren’t pumping, and I have to spend some time underneath getting things working. So, my big post about what I saw in Detroit will have to wait.

While driving north today, I read energy expert Paul Martin’s article, “The Primary Energy Fallacy- or, Committest Thou NOT the 2nd Sin of Thermodynamics!” He drags out the wonderful Livermore Sankey diagrams and explains what “rejected energy” is- the heat that is lost when we burn stuff to turn wheels or turbines. Martin notes that that we don’t need so much “primary” energy, but this isn’t news; As Allison Bailes explained, it is a function of how heat engines work. “As it turns out, we’ve known this limitation for nearly 200 years. A French kid named Sadi Carnot figured out that there’s a limit on the efficiency of heat engines.”

But what I believe Martin and others get wrong is that they are not clear about what matters, the amount of useful energy that we need.

I wrote about this in my book, The Story of Upfront Carbon, and because I have to spend the day banging my head in the crawl space trying to get my pumps to work, I am excerpting a section here.

“Electrify Everything!” is the cri de cœur as the world moves to electric mobility and heat pumps. Saul Griffith and the Rewiring America crowd say it will be easy! They write in their manifesto No Place Like Home^[1], “No “efficiency” measures such as insulation retrofits or smaller vehicles have been assumed here. Same–sized homes. Same–sized cars. Same levels of comfort. Just electric.”

One reason they say it will be easy to electrify everything is that “the electrified U.S. household uses substantially less energy than current homes.” That’s because fossil fuels are so inefficient; according to the famous Sankey drawing from the Lawrence Livermore National Laboratory, two-thirds of the energy from burning fossil fuels goes up the smokestack or out the tailpipe.  The Electrify Everything gang says we will only use 42% as much energy when we go all-electric from renewables because none will be going up in smoke.

I have never understood this; we need exactly the same useful energy, which is what they used to call it on the Sankey charts, or the exergy, not the amount of fossil fuels needed to make it. In 2021, that was 31.8 quads (Quadrillion British Thermal Units) running on coal and gasoline, and it’s 31.8 quads running on wind and sunshine. There is no massive useful energy saving simply by going renewable and all-electric.

Energy expert Michael Barnard says much the same thing^[2] in an article titled With Heat From Heat Pumps, US Energy Requirements Could Plummet By 50%.  Not really, not if you are measuring the output of a power plant, which is all that matters to the user. He explains:

“What is the primary energy fallacy? Well, it’s the belief that we have to replace all the primary energy inputs on the left-hand side of the chart above.”

I believe that the real energy fallacy is thinking that the energy inputs on the left-hand side are relevant for making anything other than CO2 and waste heat; what matters, I reiterate, is the usable energy, the exergy.

So, let’s briefly look at the math using the Livermore chart as our base.

We need 31.8 quads. We are getting all of 7.11 quads from wind, water and solar, and water is going down, not up. Nuclear isn’t going anywhere fast, so we must find 16.56 quads of green electricity in a hurry.

Barnard does note that we will probably need fewer quads of exergy.  He also suggests that heat pumps, which move heat from the air or ground, are more efficient than burning stuff to make heat, so when we convert from 3.94 quads of gas heating to electricity, it is not quad for quad, but about 2/3 less. So if every building heated with gas is converted to heat pumps, we save about 2.6 quads, some of which will be eaten up by heat pump owners discovering that they now have air conditioning.

The point here is that there has been no miraculous discovery that we only need a third as much energy. The US needs around double the low-carbon electricity it generates now or three times as much renewable energy if nuclear is not expanded.  Finding 13.96 quads of renewables is not nearly as daunting as replacing the additional 65.4 quads that went up in smoke, but it is still a challenge.

More quads of power will also be needed to deal with intermittency,- those times when the wind doesn’t blow or the sun doesn’t shine; seasonality- it takes way more energy to heat in winter than it does to cool in summer, and there is a lot less sunlight; and peak loads- when everyone comes home for dinner and turns everything on at about the same time. Those seasonal peak loads could be huge.

One study titled “Inefficient Building Electrification Will Require Massive Buildout of Renewable Energy and Seasonal Energy Storage^[3]” concluded that “All of our building electrification scenarios resulted in substantial increases in winter electrical demand, enough to switch the grid from summer to winter peaking. Meeting this peak with renewables would require a 28× increase in January wind generation, or a 303× increase in January solar, with excess generation in other months.” Others point out that this assumes no storage and no interconnections; a good grid could move power from where the wind is blowing, and the sun is shining. The study also notes that better buildings could reduce this significantly.

Indeed, what is lost when looking at the Livermore chart is that the electrical system is designed for peak loads. You can store natural gas in the ground or in the pipes to keep our homes warm and spin up the peaker plants to supply electricity, but with solar and wind, there is almost no storage capacity. Imagine a polar vortex event: The Coefficient of Performance of heat pumps drops in half in cold temperatures, so it is working flat out. Everybody’s heat pump is sucking electricity as they try and suck heat out of the cold air. It’s dinner time, and the induction range is eating kilowatts. This is the peak that the electrical system has to be designed to cope with.

The only way to cope with this is to flatten the peak. We could make our electric cars part of the system and use them to store power; we could interconnect the world with High Voltage Direct Current cables and heat Maine in winter with solar power from Arizona or Morocco. Or we could super-insulate our homes and buildings and turn them into thermal batteries, with the utility controlling our heat pumps and dialling them back when loads must be reduced.  This is where efficiency matters.

Then there is sufficiency. There is the not inconsiderable matter of the upfront carbon of making all of the electric cars, heat pumps, solar panels, wind turbines and batteries. Those are included in the industrial emissions that eat up a quarter of the quads and are difficult to decarbonize.

This is where I disagree with the Electrify Everything gang that says, “Same–sized homes. Same–sized cars. Same levels of comfort. Just electric.” I keep remembering our mantra: Use less stuff.

In 1954, the Chairman of the US Atomic Energy Commission [Lewis Strauss, the villain in Oppenheimer] said, “Our children will enjoy in their homes electrical energy too cheap to meter.” It has been taken out of context ever since, and many have noted that producing electricity is a small part of its total cost, with distribution being much more significant. Even back in 1955, others were saying^[4] that the cost of building reactors would outweigh the savings in fuel. The first director of Canada’s Chalk River research facility said, “we do not expect to produce a cheaper source of power than that derived from coal – it is likely, in fact, to be somewhat more expensive. What we are aiming at is to increase the total power available.”

Renewables are different. Build a wind or solar farm, and there is a one-time burp of upfront carbon emissions, and then it produces almost zero-cost electricity for years. A study by Deepa Venkateswaran at Bernstein Research ^[5]concluded that the steel tower was a 30% of the upfront carbon, the concrete foundation 17% and the blades 12%. The full lifecycle assessment determined that the wind turbine averages 11 grams of CO2 per kWh; natural gas comes in at 450kg, and coal, 1000kg. Other studies put it as low as 6 grams per kWh, and manufacturers also note that they are starting to use greener steel and recyclable blades, so the number is just going to get lower. Similarly, solar panels get thinner and cheaper and more efficient.

But even with renewables, electricity will never be too cheap to meter. We still have to build out a distribution system that runs around the world; we have to overbuild the system and build storage to deal with intermittency and winter peaks. And we still have to use less electricity so that we can spread it around to the half of the world’s population that still suffers from energy poverty instead hogging it all in the rich north. “Same–sized homes. Same–sized cars. Same levels of comfort. Just electric” is a fantasy. We still need sufficiency, and we still need efficiency. And it wouldn’t hurt to also design for intermittency.

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^[1] No Place Like Home https://www.rewiringamerica.org/policy/household-report

^{2} https://cleantechnica.com/2023/03/13/with-heat-from-heat-pumps-us-energy-requirements-could-plummet-by-60/

^[3] Inefficient building https://www.nature.com/articles/s41598-022-15628-2

^[4] Too cheap to meter https://web.archive.org/web/20211009091247/https://cns-snc.ca/media/media/toocheap/toocheap.html

^{5} https://www.forbes.com/sites/christopherhelman/2021/04/28/how-green-is-wind-power-really-a-new-report-tallies-up-the-carbon-cost-of-renewables/?sh=6172ff0673cd