Google is buying the output because they are increasing demand by half a nuclear power plant's worth of power. I actually think it's pretty reasonable to pass a law demanding they build an entire nuclear power plant here.
If I build a house and the demand goes up I don't have to build the solar panels (and everything else involved) to cover it, I pay the utility company to build that based on how much I'm needing to use. Well, normally I pay for whatever they think will make them the most money to deliver that much electricity - Google is specifically paying to make sure the utility company sees it as increased demand and revenue for more nuclear.
I think government regulations to put a cap on utility profits is a better long term move. Force excess to be directed into green energy expansion.
"The agreement with Fortum provides long-term financial certainty for the Loviisa plant, which currently generates about 10% of Finland's electricity.
Fortum said Google's commitment would support an investment programme aimed at extending the life of the nuclear station and increasing its generating capacity."
Long-term PPAs are what you usually want because they are bankable and give you solid demand on which to expand. Which is literally what they're talking about doing.