> and the power comes from nearby hydro plants in a very concrete sense

Unless the grid network connection is constrained, it certainly doesn’t “come” from nearby hydro because 1kWh is mostly fungible. Transmission costs are likely low. That is the point - although I admit marginal economics are confusing and most people don’t try to understand it (Disclaimer: I don’t have a good grasp of it either).

The grid connection is not likely to be constrained, because that would likely mean no redundant power. I assume even government data centers like reliable power supply: commercial data centres usually plan to be located where there is power redundancy for availability uptime. Although constraints are often only in one direction, so hard to predict just from a redundancy argument. Details of the network matter, however I am not motivated to find that exact information.

A hypothetical analogy would be to think of a lake in Lakeland. Currently the lake water is supplied 100 units by a clean green river and 100 units by a desalination plant (producing equivalently clean water, but using wads of dirty fossil fueled power to produce). 200 units of water is currently taken out of the lake by the residents of Lakeland. A data center is added that takes 50 units of water from the lake, and they sign up with the local Lakeland government that contractually agrees that the water the data centre gets from the lake is clean green water from the river. The desalination plant now needs to produce 150 units of water. Analogy: the lake is the power grid, the river is hydropower generation, and the desalination plant is fossil fuel power generation. You are saying the data center is getting water from the river (because contracts), and I am saying the extra marginal demand causes greenwashed fossil fuel generation.

> Finland uses very little fossil fuels for electricity

But nearly 100% of added power usage is supplied by non-renewable resources. That is the core of the likely greenwashing, and the point I am making about knowing where 1kWh of extra generation comes from, if 1kWh of load is marginally added.

I know I am repeating what I said, but that is because you are not arguing against the points I made.

There is a sort of argument that Finland will have 100% renewable power in the future. But if Finland has cross-connections to countries with dirty power, then the marginal argument still holds, just as though the lake in Lakeland is connected with lakes in other countries (European grid?)

To be called green:

1: add new green generation that wouldn’t otherwise be added. BUT if solar and wind generation installation is being installed at a maximum rate around the world due to manufacturing capacity limits, then you can’t claim “your” green generation unless you also increase manufacturing capacity limits. There’s a parallel to the lake analogy.

2: or reduce power usage that wouldn’t otherwise have been reduced. Usually hard to actually account for (the reduction needs is difficult to get right).

3: AND while doing the above, don’t spend a bunch of uneconomic money, because spending money is usually wasteful and indirectly generates carbon.

It is hard to do the above. However it is almost free to just label your power as “green”. Most projects choose a green label. Very very few new projects marginally reduce carbon dioxide - because new projects are usually marginal increases in power usage.