Which is why your question is so impractical. You're asking about kilotonnes of carbon on a project that will save megatonnes annually. If your question forces them to source batteries with a 10% smaller carbon footprint, you'll will likely have done net harm to the environment by delaying the project and forcing us to rely on dirty electrical sources for longer.

Your question is standard FUD technique. On the surface it appears to be a reasonable question. Because it is, at least in other contexts. But in the context of a green energy production plant, it's a distraction.

Yes, we need to make mines greener. So ask your question in the context of mines.

> Electric semis hauling freight? Not so much. The payload has to be reduced by a significant amount because the battery is so damn big.

More FUD. The batteries + motors weigh about one tonne more than the engines and diesel they displace. In response, Europe has increased weight limits for electric semis by 2 tonnes, and the US by 0.9 tons. Even if they didn't, a 1 tonne difference in a 35 tonne load is not especially significant.