Rosie51 Electricity costs 4 times as much per unit as gas. This is why people do not use electricity to heat their homes.
We had to use electricity to heat our kitchen and family room for a whole winter while building work was taking place. The rest of the house was still able to be heated with the gas central heating. It increased our fuel bills by £several hubdred. We were very relieved when it could be reconnected to the main heating system.
If you want to know where our power is made and what from I reccommend Gridwatch gridwatch.co.uk/.
Currently wind power is providing only 17% of our electricity, as in most places, in cold snaps like this, there is very ittle wind. 57% is being produced by gas. Any electricity inported from France will almost undoubtedly be nuclear.
Allira Tide power comes in two different forms, The first is from the movement of the sea and research has been going into this for 30-40 years. The big problems are that the sea can be anything from glassy smooth with a slight swell to 5-10 metre high waves (and more) with huge swells and designing equipment capable of dealing with such a huge range of conditions and, importantly the cable connection to shore is very, very difficult. Also sea water is highly corrosive and making all the equipment sufficiently corrosion resistant is proving a challenge.
The other way the sea can be used is by working with the tide. For a tidal power station you need an area with a high rise and fall of he tide, ideally a minimum of 5 metres, France has a tidal power station in Brittany, near St Malo. I have visited it.
General de Gaulle opened it in 1964, and it is still operational. The turbines have been replaced several times.
There were plans some years to build such a tidal barrage and power station in the Severn estuary, but it was voted out. There was another plan to build a whole series of barrages down the South Wales coast - the Bristol channel is the only place in England with big enough tides - Unfortunately the then government refused to finance it. Together the barrages could have supplied 30% of our electricity.
Hydro power is a bit of a non-starter in the UK . For large hydro power stations you need high mountains and big rivers - and we have neither.
There are a couple of stations in Wales, but their output is small. The biggest, and best known, Dinorwic actually uses low power demand periods to pump water up to its reservoir above the power station, and in times of high demand relaeses the water to generate power. so is not a true hydro power resource.