Yes, many offshore windfarms will do this. At about 40GBp, in somewhat current tendering (Contract for difference (CFD) auction round 3, UK). Although normally on a 15 year period (for arbitrary reasons Hinkley Point C was allowed a 35 year period and did not participate in the 2015 CFD auction).

I think anyone would love to offer a CFD over a 35 year timeline, only HinkleyPoint C (and Sizewell C in the same agreement) where offered these conditions. i.e it makes financing much easier.

HinkleyPoint C is in planning since 2008 or so, not exactly a quick process. Real construction since 2018 (but some prep work done in the decade leading up to this.) Expected generation is in 2025/2026. This sounds bad but is actually decent, 10 years from idea to generation is common and outliers exist in both directions.

Do you know where I could read more about this scheme?

How do they guarantee that they will actually provide the energy at a given time? Are they pairing wind with another power plant?

That is not what is guaranteed (nor at Hinkley Point C (HPC)), what is guaranteed that in the period a Mw produced for the grid is paid at least the strike price (but maybe more). Hinkley Point C will have have downtime for refuelling and other reasons. So needs to be paired with another power plant.

The CFD for hinkley point is available and is a few hundred pages.

Part of reason for the strike price with HPC is that they expected offshore to cost 85 GBP in 2025, while it costs 50 GBP in 2020.

I don't think that the downtime of a nuclear reactor is similar to wind and solar (less often and can be scheduled).

Thanks for the explanation on CFD. One of the advantages of nuclear is its predictability, it seems unfortunate if this isn't what was bought by the UK.