By AMY BETH HANSON
HELENA, Mont. (AP) — With the cryptocurrency industry under increasing pressure to rein in the environmental impact of the massive amounts of electricity it uses to power computers verifying transactions, some companies mining bitcoin are looking to switch to renewable energy. Many economists and environmentalists have warned that as the still widely misunderstood digital currency grows in price and popularity the process of mining that is central to its existence and value is becoming increasingly energy intensive and potentially unsustainable. For one company that has thousands of computers based at a coal-fired power plant in rural Montana, that means relocating to a wind farm in Texas.