If governments forced miners to use solar energy only, would Bitcoin become more sustainable and valuable, or would it reduce mining capacity drastically?
Mining is mining, it can be done in any way, if solar can produce such high energy, then in that case Bitcoin mining can also be done with it. But it will require a very large setup. Because if many solar panels are placed in one place, it can produce high energy. But I don't think the government of any country will take such a decision. Because by mining Bitcoin, that country can develop economically because the price of Bitcoin is increasing a lot, everyone considers Bitcoin as digital gold, so the government will pay more attention to Bitcoin mining.