The machines are the heart of the New York-based company, which makes money by plugging the high-powered computers into cheap electricity sources so they can work through mathematical problems to unlock new bitcoin. The process, called mining, has gone from something any individual with a PC could do a decade ago, to a massive industry that uses numerous computers and lots of electricity. Bit Digital and other cryptocurrency mining companies now face many hurdles as they move their machines out of a country that previously used two-thirds of the global energy dedicated to harvesting bitcoin. The machines are prone to…