Google has more clean power than it needs. The Alphabet Inc. unit used about 7 terawatt-hours of electricity to run all of its global operations last year, and it sourced even more than that, according to Neha Palmer, its head of energy strategy. Corporate buyers are major purchasers of wind and solar power. While part of the motivation is to advance sustainability goals, they're also finding that clean energy is often the cheapest electricity available. Big technology companies have been leading this trend, and Google has been the biggest of them all. Our electric consumption is the largest part of our carbon footprint," Palmer said in a phone interview. "The renewable-energy program we have is the best way to mitigate our carbon impact." Companies signed long-term agreements for a record 5.4 gigawatts of clean capacity globally last year, according to Bloomberg New Energy Finance, up from 4.3 gigawatts in 2016. That's enough to displace at least 10 coal-fired power plants. Google signed its first clean power-purchase agreement in 2010, and since then it's arranged about 25 more, prompting more than $3 billion in new clean-power plants. Google has agreed to buy ... more than double that of Amazon.com Inc., the next biggest green consumer. "It's a significant investment, leading to lots of new renewables projects," Kyle Harrison, a New York-based analyst ... said. "It's a long-term bet on clean energy, a hedge against wholesale prices."