this post was submitted on 17 Jun 2024
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I tested a 55,000-pound electric excavator. New ways to power off-road machines, which mostly run on diesel, could cut about 3 percent of U.S. carbon emissions.

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[–] TWeaK@lemm.ee -4 points 5 months ago (5 children)

Lol how do you think construction sites generate electricity to charge the batteries?

[–] ealoe@ani.social 13 points 5 months ago (1 children)

You're saying this like sort of gotcha, but larger generators can be a lot more efficient than a smaller engine so even running a large diesel generator 24/7 to charge a battery is likely an improvement over a gas powered digger. Same reason powering an EV with a coal power plant is still a win over a gas car, bigger engines are more efficient.

[–] TWeaK@lemm.ee -3 points 5 months ago

Yeah I was aware of that as I posted it. I work on construction sites. More than anything I was highlighting how vehicles isn't the only problem.

[–] silence7@slrpnk.net 11 points 5 months ago (2 children)

Three ways:

  • They can prioritize bringing power to the site, and do that first
  • They can use a trailer with solar panels, as is currently done today for lighting and tools
  • For equipment which sees limited use, simply bring it to the site already-charged

Electric equipment doesn't need to be a 100% replacement to make a big difference.

[–] Bilbo_Haggins@lemm.ee 2 points 5 months ago

You would need a pretty big solar array to power a construction site with it. But you're headed in the right direction. Not only is it an option to use renewables to power battery-powered vehicles, but also pretty much any form of electricity generation increases in efficiency and decreases in emissions (per kilowatt generated) as it scales up. Even if you are burning the same fuel at the power plant, the emissions are going to be lower overall than the equivalent number of individual internal combustion engines because the efficiency of the power plant is much higher than an ICE. Vehicle engines are ridiculously inefficient overall and when you use a more efficient fuel like natural gas it is even more drastic of a difference.

It's also much easier to put stack controls on a power plant to capture or reduce emissions than it is to put emissions controls on all construction equipment individually. This has implications for carbon capture, which could happen right at the stack. However, there's a non-climate change benefit here as well which is that the local air quality would be greatly increased around construction sites. Currently most construction equipment does not have much in the way of emissions controls for other things like sulfur and nitrogen oxides or particulate emissions. Power plants have to meet emissions standards for all of these.

[–] TWeaK@lemm.ee 2 points 5 months ago
  1. It's not always practical to get power to a site, depending on the utility and whatever upgrades they need.
  2. Solar doesn't generate enough, and doesn't generate at all overnight (when plant would be charged).
  3. Most plant lives on site and transporting it off site to charge is just going to add to costs and likely increase pollution (you need lorries to move them).

It's a good idea, and one that's growing, but it's still niche and it will be a long time before construction sites are fully electric.

[–] Auzy@beehaw.org 4 points 5 months ago* (last edited 5 months ago) (1 children)

I don't remember ever seeing a construction site here in Australia which generated power using a generator. Most of them simply run a temporary power connection

I've been to so many at this point

[–] TWeaK@lemm.ee 3 points 5 months ago

I'm guessing you don't actually work on the sites. Generators are often in containers and not necessarily obvious, or out of the way. Depends on the site and what the job is, though.

In general, a site would prefer to have a proper connection (cheaper), but more often than not it's not available.

[–] JoshuaFalken@lemmy.world 3 points 5 months ago

I see what you're saying, but it wasn't too long ago a similar sentiment was said of motorized construction and farm equipment.

Ultimately, if each piece of equipment had a viable electric alternative that would operate all day without needing a charge, it wouldn't take that smart of a bean counter to realize there were a lot of savings to be had if they started projects with an electrical charging area for the new equipment that could potentially be repurposed for customer or resident charging once the job was done.

It would become an anticipated start-up cost, similar to the transport of the equipment itself, delivery of materials, set up of portable offices and toilets and the like. Obviously this would be out of reach for a small operation, but a company that's building out row houses or shopping centres I could see making the switch.

[–] OutsizedWalrus@lemmy.world 1 points 5 months ago

One thing that is beneficial is efficiency of internal combustion engines tends to scale with size.

One met generator is more efficient that smaller engines on each vehicle.

Also, a lot of small equipment isn’t being used all day. You might dig a trench, work in it all day, then fire the machine back up to fill the trench.