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It's easy to make a gas turbine that will run on pure hydrogen as a fuel. All that's required is a willingness to accept excessively high levels of NOx emissions. A gas turbine that will run cleanly on pure hydrogen is more difficult, but still possible if one is willing to give up enough efficiency. Making one that will run both cleanly and with high efficiency is, AFAIK, a still-unsolved challenge.

It's not clear to me that the Norwegian team in the referenced article has solved that challenge. In fact, I infer from the article that they haven't. They do mention a loss of thermal efficiency for power generation. Since they're using the turbine in a system for combined heat and power, thermal efficiency for power generation isn't especially important. Thermal energy not captured in the power output is captured as low grade waste energy for the "heat" side of the application.

If hydrogen is to be used for backup generation for wind and solar resources, then it makes more sense to use fuel cells rather than gas turbines.