U.S. technology companies are pursuing energy assets held by bitcoin miners as they race to secure a shrinking supply of electricity for their rapidly expanding artificial intelligence and cloud computing data centers. Those data centers are driving the fastest U.S. power demand growth since the start of the millennium, outpacing grid expansions and leaving giant technology companies, like Amazon and Microsoft, to scavenge for vast amounts of electricity.

The electricity scramble is jolting the energy-intensive cryptocurrency mining industry. Some miners are making huge profits leasing or selling their power-connected infrastructure and sites to tech, while others are losing access to the electricity needed to stay in business. “The AI battle for dominance is a battle being had by the biggest and best capitalized companies in the world and they care like their lives depend on it that they win,” said Greg Beard, CEO of Stronghold Digital Mining, a publicly-traded bitcoin mining company. “Do they care about what they pay for power? Probably not.”

Data centers could use up to 9% of total electricity generated in the U.S. by the end of the decade, more than doubling their current consumption, as technology companies pour funds into expanding their computing hubs, the Electric Power Research Institute said in May.

Currently, data centers account for about 1%-1.3% of global electricity consumption, versus crypto mining’s roughly 0.4%, according to the International Energy Agency. That disparity is expected to grow.