I've read somewhere that if we don't agree fishing quotas after this new deal expires in 2025 they can turn the lights off here.
That probably explains this:
https://www.gov.uk/government/news/uk-and-norway-sign-historic-fisheries-agreementRegarding gas, imports from Norway are roughly 40%, domestic production is roughly 33%, with 20% from the European mainland network (probably a lot of that from Russia itself), while roughly 7% is LNG from Qatar.
I don't see a problem. We have the gas pretty much tied up and could generate a great deal of our own required electricity through a mixture of coal, nuclear and renewable resources. We import electricity from the Continental transmission system, but that's only a small percentage of the overall requirement and demanded as market fluctuations require. According to the following link, burning fossil fuels accounts for roughly 54.1% of supply, which means that gas imports from and via Europe and Russia account for only around just under 11% of electricity generation.
https://www.energy-uk.org.uk/our-work/generation/electricity-generation.html#:~:text=Most%20of%20the%20UK's%20electricity,(3.1%25%20in%202016)
It seems that Norway is strategically important to us because although they are an EEA state, they are outside the EU itself, meaning they aren't signed up to the Common Fisheries Policy and can deal with us independently. They have their own bilateral fisheries agreement with the EU:
https://ec.europa.eu/fisheries/press/eu-and-norway-reach-agreement-fisheries-arrangements-2020_en
