The love of Apple, Google, and other data center companies for solar power from companies like First Solar has less to do with idealism and more to do with business practicality.
It’s the oldest trick in the financial book, a hedge you can write a bond on.
Electricity is an input cost to a data center operator, or to anyone with a lot of electronics. If you’re going to plan ahead, and these companies now think in terms of decades ahead, you’re going to want to predict that cost.
Solar power makes the cost predictable. You buy X number of panels delivering Y amount of megawatts, with a life expectancy of Z. You put that capital cost into a sinking fund, a lease, or a mortgage, and you let time do the rest. Now you know what your costs for electricity are going to be next year, and the year after that, and 10 years down the road.
Whatever the other claimed benefits of fossil fuels, they can’t deliver that certainty. This is especially true for California utilities, whose costs (and rates) can vary considerably from place-to-place. A lot depends on the cost of fuel. That may be low today, but it may be higher tomorrow. Whatever the cost, it’s not fixed.