The study is not showing what you think it do:
> system costs are comprised by overcapacity of the technology itself, electrolysers and hydrogen storage, back-up power, influence on spinning reserve and transmission systems cost.
Green hydrogen storage solution has shown to be much more expensive than what earlier studies predicted, and are still not economical competitive to be used in industries that need the hydrogen itself rather than burning it for electricity.
> Thus, the simulation of, e.g., nuclear power involves back-up-power and peak-load power in order to cover all hourly electricity demands in a least-cost manner
This is an assumption that they don't explore.
> It should be emphasized that all the alternatives have exactly the same use of biomass and they all contribute with carbon for CCU, CCS and biochar to achieve a fully climate neutral society in all sectors including agriculture, industrial processes and LULUCF.
Again, they explicitly claim that all their solutions must burn fuel for electricity.
> The “LC mix biomass restricted” alternative is still comprised by a least-cost combination of offshore wind power (84%), solar PV (13%) and CCGT (3%)
> CCGT and therefore also the least-cost mix either use natural gas or biomethane
CCGT, as is thermal power plants, which is what is exactly what Sweden is constructing and what I linked above. A combination of wind, solar, and burning fuel for power. The difference between LC mix biomass restricted and least cost mix is how much fuel that grid is expected to burn.
Their model of just 3% CCGT do fly a bit against what Denmark is doing. They have over 100% wind capacity, and yet need to import almost 50% of the energy demand. Reducing that imports to 3% seems a bit like wishful thinking.
If the intent was disprove the need for thermal power plants by linking to that study, then the study itself disproves that in no unclear terms. The result of the study is that combining wind, solar and gas is the cheapest strategy to generate electricity.