The thing which amazes me is the fact that we are an island, and all around our coast the sea rises and falls twice a day every day without fail, yet all the money goes to unreliable wind & sun. Also we have a range of hills running through most of the country with fast flowing streams and rivers running off them and don't and tap them for hydro power, and there must be hundreds of derelict water mills which could be cheaply converted.
You're quite correct, I'm sure. Water power, of one sort or another, is much more reliable than wind. Some may argue, perhaps, that droughts might have an effect, but certainly tides will never stop rising and falling.