The problem with some renewable electricity schemes is that the wind doesn’t always blow, and there’s no sunshine at night or for very long in winter.

However, there’s one energy source that happens like clockwork – the tides. They are dependable, day in and day out, and even though they change in height and the time of the day, they are predictable.

But tidal energy is beset with problems, and one is the level of opposition. It’s similar to the protests by ramblers and residents fighting the proposal to double the size of the pylons that bring renewable power from the Scottish seas and highlands to the industrial lowlands.

This conflict between landscape, wildlife and the need for carbon-free renewable energy is particularly well-illustrated in the proposal for a barrage built across the estuary of the River Severn.

The Bristol Channel leads funnel-like into the mouth of the Severn and this produces one of the highest tidal ranges in the world, almost 50ft, so it might be possible to harness it following the example of the Rance scheme in northern France. It was completed in 1966, and now produces cheaper electricity than nuclear sources.

A Severn barrage was first suggested more than 150 years ago, but with fossil fuels being abundant and relatively cheap, it wasn’t until the 1980s that real interest developed. The first proposal was to build a barrier from Somerset to Cardiff, and it was estimated it could produce six per cent of the UK’s electricity, the same as three nuclear power stations, though at the cost of six of them.

There are now suggestions for shorter barrages further inland, as well as designs that produce power at all states of the tide, and even lagoons that trap the water in the same way as pumped storage schemes.

The public will be consulted on eight different proposals later this year, but any development must comply with the European Habitat and Birds Directive because the estuary is the largest wading bird site in Europe, and it might need to be publicly supported to ensure a competitive price for the electricity produced. The financial burden of the private Channel Tunnel, a similar large-scale engineering endeavour, isn’t encouraging.

It’s not surprising that environmentalists, farmers, fishing groups and Severn bore surfers are opposed to the scale of these schemes, and the amount of concrete involved, at one tonne of CO2 for every tonne of cement, is also a significant problem. As these proposals could take up to 20 years to build, we would be better off with a proven technology we can depend on – a new generation of carbon-free nuclear power stations.