It is so sad for this country that started its first Industrial revolution using standard wall wheels to drive the cotton Jennie's until the progress of steam power, that's why all large mills were sited on river banks.
The modern academia has lost the understanding of the basic principles of energy collection and all use the standard horizontal axis propeller turbine design model which needs both fast and smooth flows to operate the lift action which imparts rotation.
The other problem with propellers is they leave a heavy rotational wake which scours the sea or river bed.
However, Reaction turbines like the Hales Turbine have been tested on the Thames and in a specially built test tank to produce 35% efficiency from just 1.0 m/s flows which is already better than modern off shore wind turbines that operate at only 30% efficiency for the area they sweep.
There is enough Ebb flows through the narrow pool of London area to power both the HOP and City Hall. On top of that the special Heat Transfer Arrays that we designed and patented would supply enough heat or cooling to operate both buildings.
The UK has the greatest area of tidal stream waters in the world but lack of basic understanding has resulted in this Energy Crisis.