I don't think the miners can exactly decentralize the energy grid but they have definitely helped grow the grid on many occasions, some of which were actually very positive. For example a couple of years ago I read something about our government working with the miners to work on infrastructure to use the Gas Flare (wasted gas produced during gas and oil extraction) to generate electricity. Something that led to establishing massive projects to catch and use a whopping 20 million cubic meter flare gas (700 million cubic feet) on a daily basis.
Bitcoin miners can operate more concentrative or more decentralized and this Bitcoin miners and mining hashrate distribution status are not static, but very dynamic and change over time. It depends on national policies that support Bitcoin mining or against Bitcoin mining with a China crack down on Bitcoin mining in 2021 and the Great Hashrate Migration after that to other countries are very good examples.
Generally, it's fortunately that Bitcoin hashrate has become bigger over time with better Bitcoin adoption to make Bitcoin safer and more profitable for investors and miners. Hence, there are more new Bitcoin mining farms that spread over the world and increase Bitcoin hashrate decentralization, then Bitcoin node decentralization as well.
It can have some impacts on electricity grid as Bitcoin mining farms will set up their necessary infrastructures for mining.