r/Renewable • u/Grand-Moose-9287 • Sep 16 '26
What are the options for heavy machinery?
How will heavy machinery, such as excavators, dumpers and so forth be powered in a renewable future? If electric, how would they be charged if no grid connection is available on site?
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u/WeAreSolarAF Sep 17 '26
Battery power per unit of weight will increase, maybe from different materials. Some have indicated that you can use the frame of the vehicle as a battery someday.
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u/Healthy_Article_2237 Sep 16 '26
We aren’t there yet battery wise. These are used so infrequently compared to autos that it doesn’t make sense to develop changes right away. We’ll still use liquid fuel for years. Airplanes too.
The great thing is if we can get autos and even commercial trucking and trains electrified then things like heavy machinery can be run on biodiesel. Jet fuel might still need traditional hydrocarbons for a while due to the demand. More electrified high speed rail could help that.
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u/theturbineguy 27d ago
Imo yes because they can handle the weight over many many batteries.
And id argue that there should be an option for attaching a charging cable to it so they can pull from the grid when possible as they are working extending operations
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u/jackwilliam76 19d ago
Electric heavy equipment is becoming a practical option for many construction projects, especially smaller machines.
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u/Berkamin Sep 16 '26
If high energy density is needed, renewable fuel of some sort will probably be the best solution. Renewable hydrogen can run fuel cells, or some hydrogen rich molecule such as methanol can be reformed onboard, or a hydrogen rich metal hydride can be decomposed to release hydrogen. Alternatively biodiesel, bio-butanol, bio-methane, cellulosic ethanol, algae biodiesel, or some other biofuel for direct combustion might be used.
The reason for this assessment is that it is really hard to make high energy density batteries. Some of the new batteries that react with air such as zinc-air or lithium-air batteries have substantially improved energy density, but it is easier and likely more cost effective to produce renewable fuels that react with air through fuel cells or combustion than it is to use metal-air batteries that oxidize the metal.
See the Wikipedia entry on energy density. All the batteries are concentrated in the lower left. All the fuels have far higher energy density.
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u/lawmac20 Sep 17 '26
I like the e-fuel variants over the bio at the moment.
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u/Berkamin Sep 17 '26
I also prefer e-fuels. The most efficient plants only convert around 1% of the sunlight that they receive into chemical forms of energy, whereas solar panels nowadays are somewhere between 20-25% efficient. Algae may be somewhat more efficient, but not by that much. I don't know precisely how efficient the next conversion from electricity to some sort of fuel is, but with that margin of advantage over plants, even if the next stage is substantially less efficient, it is likely to beat plants. The only thing about algae and plants that differ is that they can sometimes be more cost-effective just because they bring a lot of biological infrastructure. In the end, efficiency factors into a larger equation to determine cost effectiveness. The most efficient tech is not always the most cost-effective tech, and as long as you have to operate within an economic system, cost-effectiveness wins in the long run, even if it is based on something less efficient.
I wrote a post critically examining algae based fuels to see when they would still be worth trying. See this:
You guys are fantasizing about the wrong algae tech. Don't fantasize about tanks of sludge; fantasize about algal biofilm reactors.
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u/PM_ME_YOUR_HAGGIS_ Sep 16 '26
Batteries and bigger batteries on the back of battery powered trucks.