To comprehend energy on a large scale in the United States, you can’t do much better than studying the energy flow charts from the Lawrence Livermore National Lab (part of the United States Department of Energy). In the 2023 variation above, you see the numerous fuels we use on the left. On the right you see the outputs. And the important things almost everyone notices immediately is the substantial piece called turned down energy.
The origin of declined energy
In a previous post on rejected energy, I discussed why it exists and how resistant it is to decrease as long as we keep our present fossil-heavy mix of fuels. “The very first thing to comprehend is that the great bulk of that turned down energy originates from burning fuels,” I composed. Then we convert the heat of combustion to mechanical operate in vehicles and other devices. Or we go an action further and turn the mechanical work into electricity.
However we can’t ever use all of the heat energy we receive from burning those fuels. Here’s what I blogged about that:
As it ends up, we have actually understood this constraint for almost 200 years. A French kid named Sadi Carnot determined that there’s a limit on the efficiency of heat engines. † He discovered the thermodynamic cycle that yields the maximum performance of a heat engine. His work is so crucial in thermodynamics that his optimum theoretical effectiveness is called the Carnot effectiveness.
There’s more about turned down energy and the Lawrence Livermore charts in that article, so you may wish to click over there and read it.
Can we reduce turned down energy to zero?
The main point of this post is reducing that excess heat we’re not able to use. As I wrote in the previous post, “Performance isn’t the solution to declined energy.” Yes, it can suffice down some, however we’re still playing a percentages game.
The only method to make an enormous dent in it is to stop burning things. Even that would still leave some, though, mainly because of two things: nuclear power production and electrical losses.
Nuclear reactor make as much declined energy as coal and gas plants. Image of Plant Vogtle from United States Dept. of Energy Nuclear power plants do not burn a fuel to make heat, but they’re still working as heat engines. That implies they’re still based on the Carnot efficiency limits. See those huge cooling towers above? That’s how they get rid of the waste heat from the plant, which turns out to be kind of crucial. (Search for 3 Mile Island and Chernobyl.)
Electrical losses likewise contribute to the total amount of declined energy. When electrical energy takes a trip through the power lines to your house, a few of that energy goes to warming the wires. And we lose more in the end uses.
An air conditioning system supplies a perfect example of end-use losses. When we do cooling-load calculations at Energy Lead, we consist of the internal loads. When you switch on a light or a fan or an electrical oven, all the electrical energy you utilize eventually turns into heat. Most of that heat remains in your home, which is why we include it in load calculations.
So the answer is no. We can not reduce declined energy to zero.
Do solar and wind add to turned down energy?
When the source of our energy is photovoltaics and wind turbines, they’re not 100 percent efficient. Current photovoltaic (PV) modules, for instance, are about 22 percent efficient at transforming sunlight to electrical power. So should we count the other 78 percent as turned down energy?
No. The excess solar power doesn’t alter kind. It doesn’t create contamination. And it doesn’t cost anything. The exact same is true for wind.
This roof photovoltaic system generates solar electricity without any declined energy. However as quickly as we begin moving that energy from the modules or turbines through wires, we begin getting some declined energy. Exact same for running it through inverters to transform between DC and AC or storing it in batteries.
How low can we go?
The most recent LLNL energy flowchart (lead image above) shows that we used 93.6 quadrillion BTUs (quads) of primary energy in 2023. Of that, only 32.1 quads was useful energy that moved automobiles, heated homes, and made stuff. The other 61.5 quads was turned down, mainly as waste heat.
To come up with a price quote of how low we can choose declined energy if we used only solar, wind, and other renewable sources, I asked claude.ai. The answer was 8 to 12 quads. That’s only 13 to 20 percent of the rejected energy in our present system.
So if we presently need 93.6 quads of primary energy to get 32.1 quads of functional energy, we would require just about 40 to 52 quads of primary energy without the fossil and nuclear. So instead of using just about a 3rd of the energy we’re producing, we ‘d be using 60 to 80 percent.
The real takeaways
Comprehending turned down energy is very important. But the service isn’t finding a way to make much better use of all that waste heat. That would mean those thermal power plants (fossil and nuclear) would require to be near locations that might make use of the excess heat for water and area heating. That ain’t gon na take place to any terrific extent.
What this analysis really suggests is that we require to concentrate on the right numbers. To do everything we’re doing now, we don’t require to change the entire amount of primary energy (94 quads in 2023). We need about half of that, perhaps a bit more. Include nuclear, which isn’t going away, and it’s a bit greater.
Here’s a summary of the important points:
- We can not take rejected energy all the way down to absolutely no.
- Turned down energy comes from nuclear power generation, too, however nuclear doesn’t featured the exact same carbon and contamination problem as fossil fuels. (It does still featured the problems of safety dangers, hazardous waste, and a significantly high price, as Georgia Power proved again.)
- Solar and wind don’t create turned down energy throughout production, but there are losses with renewably created electrical power afterward.
- We do not require to replace the amount of energy on the input side of the chart. For the exact same beneficial energy we received from the inputs in 2023, we might require only 40 to 50 quads with solar and wind rather of the 94 quads it took in our present energy system.
So if you wish to minimize the amount of energy that gets turned down, solar and wind are the way to go.
The Claude analysis
I turned the analysis from claude.ai into an artifact. Click that link to read it.
Afterword
Quickly after releasing this post, I received Lloyd Alter’s latest short article in my inbox. It’s about the US Secretary of Energy saying he wants to “let loose” 35 gigawatts of diesel-fueled electrical generators to assist power America. Ugh!
† Carnot was only 28 when he figured this out.
Allison A. Bailes III, PhD is a speaker, writer, constructing science expert, and the creator of Energy Vanguard in Decatur, Georgia. He has a doctorate in physics and is the author of a successful book on structure science. He likewise writes the Energy Vanguard Blog. For more updates, you can follow Allison on LinkedIn and sign up for Energy Lead’s weekly newsletter and YouTube channel.
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