Renewable ERoEI’s better because they don’t waste heat? Huh?

A comment by Heavyweather led me to the Bountiful Energy blog, which made such a strange claim that I thought it deserved a blog post. They argument is that the waste heat in fossil fuel plants should be counted in the EROEI.

Take this graph as an example. It compares the ERoEI of solar PV for electrical power, against the ERoEI of coal and gas for heat. That comparison is invalid, because it’s an apples-to-oranges comparison. Thermal power plants (like coal-burning plants) waste approximately 2/3ds of their energy as waste heat. Waste heat is radiated out into the atmosphere from the power plant, and provides no energy services to society. This massive energy loss from fossil fuels is not counted in that graph of ERoEI, thereby artificially inflating the ERoEI of fossil fuels. If we subtract the energy losses from conversion of thermal energy to electricity, then the ERoEI of fossil fuels declines by approximately 2/3rds relative to solar PV. Conversely, we could also increase the ERoEI of solar PV by approximately 3x, thereby providing an energy quality correction. As a result, the ERoEI for thermal power plants which generate electricity is approximately 2/3rds lower than the graph indicates, or (conversely) the ERoEI of solar PV is approximately 3x higher.

As I understood ERoEI, the claims were that x amounts of coal or oil or gas delivered y amounts of useful work. That is, x coal delivers y electricity or heating or whatever. The thermal losses in the process might be terribly inefficient, but y still gets done. The thermal losses might warrant reinventing how they build power plants to capture some of that waste heat for the local houses, but y still gets done. The sheer waste of heat might make you want to pull your hair out, but y still gets done! That’s the point. They’re measuring what x coal actually does: how much power it produces, how much it heats homes, whatever.

This is not theoretical. There’s so much energy in fossil fuels that even when we use them badly, they still have enough left over energy to run our power grids and move our cars. (And I agree that everybody driving internal combustion engines has to the most wasteful uses of our precious but polluting oil. It is so terribly inefficient with only a tiny fraction of that oil energy actually causing forward motion!)

 But this is where Bountiful Energy’s thermal argument collapses. Looking at waste heat and then subtracting that off the work coal actually does is nonsense. If anything it makes the overall energy return potential of fossil fuels better! For if x coal produces Y work in an inefficient power plant, will not x coal produce 2y or 3y in a really good Combined Heat & Power plant? Why on earth does Bountiful Energy subtract the potentially greater energy supply from the original work of Y? Y still gets done! That’s what they are measuring: what actually gets done. Then artificially inflating solar PV’s work by saying “At least it doesn’t waste thermal heat!” is ridiculous. Solar still only does what it does. Solar PV takes X (the best third of the day’s sunshine) and turns it into Y energy. This is measurable. We can argue over what else to include in the net energy cost of building those solar panels, but that X sunshine = Y electricity is not really a debate. Or is it? What about night time and winter? We’ll get to that. My point for now is that you cannot argue that X sunshine = 3Y electricity just because it doesn’t waste heat energy!

 

Also, Bountiful Energy has forgotten storage. Renewables are intermittent and require backup. My argument for years (along with that of such ‘lightweights’ as Dr James Hansen, the very man who helped explain our climate emergency!) is that building a renewable grid requires SO much overbuild in smart grids, super-sized grids, over-capacity wind farms and solar farms, and so much money wasted in STORAGE, that it would bankrupt any nation that tried. This has been documented. Germany has wasted hundreds of billions on their solar PV scheme which could have build 3 times as much power in reliable baseload nuclear power plants that run day and night, even on cloudy winter evenings!

 

BUT EVEN RENEWABLE’S TERRIBLE COST PALES INTO INSIGNIFICANCE next to the laws of physics which state that renewables PLUS STORAGE may not even be an energy source in the first place! It takes so much energy to roll out the STORAGE we need for cold, windless winter nights that when counting the energy cost of the storage, we solar PV may actually become a net energy SINK! That is, X coal and oil and gas consumed in the construction of solar PV + storage = marginally less Y. Solar PV + storage = coal in disguise.

Not only this, but we need a minimum of 12 times the energy return on energy invested (ERoEI) to run the modern world.

Solar thermal is the best. Solar thermal + storage gives us a net return of 9 times the energy it took to build it.

Wind + storage is 3.9, and solar PV might only be 1.6, or really not even an energy source in some places. Sorry folks. The ERoEI of a renewable grid + storage seems to be too low. Nuclear has an ERoEI of about 75. It’s nuclear or it’s climate change. The latest papers by Weißbach explains why.

 

morganesfig1

 

Lastly, banning nukes because of Fukishima is like banning modern aviation because of the Hindenberg. They were tired old Gen2 reactors and did not have today’s passive safety systems. Why passive? Because they are safe without Homer Simpson having to remember to push any buttons. They are also called ‘walk away’ reactors. “Oh, the reactor’s overheating: let’s go get a cup of coffee.” The passive safety systems in the very laws of physics take over. So that’s today’s Gen3.5 reactors. Tomorrow’s reactors will eat nuclear waste! Indeed, nuclear waste is no longer a problem to store for 100,000 years but could power our world for about 500 years. (Well, at least the UK has enough to run themselves for the next 500 years and America for the next thousand!) And it’s ‘renewable’ because erosion keeps topping up our oceans with more and more uranium particles. Uranium from seawater is now economically viable if our land based uranium mines. But now that we can burn waste, uranium (and thorium) on land will not run out for the next 50,000 years at least.

Nuclear power is safe, burns nuclear waste, has abundant fuel forever (well at least until the sun expands and wipes out life on earth) and is BASELOAD: it doesn’t need backup. As a result, the World Nuclear Association says nuclear’s ERoEI is from 40 to 60. That’s plenty of energy left over to manufacture hydrogen and synfuels and electric cars to replace oil and run our electricity grids.

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2 Responses to Renewable ERoEI’s better because they don’t waste heat? Huh?

  1. Hi, I responded to your comment on the bountiful energy blog.

    Regards,
    Tom S

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