Fiona Harvey Farewell, Severn barrage, and several decades’ work

So farewell, then, Severn Barrage.

The idea of an electricity-generating barrage across the Severn estuary has been around for nearly as long as electricity generation itself. Writing on the subject several years ago, I was delighted to receive a letter from a reader who had been present at a public meeting to push forward work on such a barrage – in 1929.

It is hardly surprising, as the Severn is an ideal place for tidal power generation. It has one of the highest “tidal reaches”, or differences between high and low tide, in the world.

Tidal power is – unlike other renewable forms of energy such as wind power – utterly reliable, as any tidal generator will produce power as long as the moon is in the sky.

The barrage proposal that the government has just turned down would cover at least 5 per cent of the UK’s electricity needs. That would have been a massive contribution to the UK’s energy security.

But a barrage would be costly. The price tag for the proposed 10-mile barrage across the estuary was estimated at about £30bn – and such estimates only ever move upwards, in reality.

The hefty price would mean the government – ie the taxpayer – would have to put up a lot of the capital. The rewards would be correspondingly enormous – once in operation, the barrage could carry on with relatively cheap maintenance for decades, as have other long-running tidal schemes, generating huge profits as well as clean energy. But those benefits would not start to accrue for some years, and certainly not before the next general election.

Expensive long-term investment is not on the government’s mind at present. The comprehensive spending review is focusing on cuts. In that context, it could hardly be expected that such a big project would get funding.

The proposed barrage was also controversial – some environmental groups opposed it on the grounds that it could disrupt wildlife and damage an important breeding ground for birds, while some businesses were worried about its effects on shipping.

All is not lost for tidal energy in the Severn, however. The government has not ruled out allowing one of the smaller proposed projects – which could be set up without government funding, and could be profitable on the basis of energy and carbon prices alone – to go ahead.

If any of these projects – which would generate far less electricity than the proposed barrage – do come to pass, that will be the final nail in the coffin of what could have been the biggest renewable electricity project in Europe, and one of the biggest in the world. It is unlikely that a barrage could be reinstated if other tidal projects were operating.

So the work of decades has come to nothing. But there is always offshore wind…