Swansea Bay Tidal Lagoon and Baseload Tidal Generation in the UK
By Paul Homewood
The project would see energy produced for 14 out of every 24 hours, according to TLP
We are well aware of the problems of intermittency with the proposed tidal lagoon at Swansea Bay. Even the developers, TLP, admit it can only supply power for 14 hours a day.
But they also propose to build a chain of other lagoons, which they claim overcome this problem because of differences in high tide times around the coast.
Euan Mearns has tested this claim by carrying out a detailed study of tides at the sites likely to be developed. His verdict is that even with staggered tide times, the issue of intermittency remains, with four spikes separated by four periods of zero production every day.
Charles Hendry, former energy secretary, published his long awaited report on the Swansea Bay tidal lagoon power station last week coming down in favour of the project. Hendry’s report is comprehensive but has one key omission. It does not ask if tidal lagoons can provide renewable base-load power in the UK as is often claimed. I set out in a positive frame of mind to show that it could, but failed miserably in that attempt. Facts defeated me.
The timing of high and low tides are staggered around the coast of Britain. Hence, the ideology says that combining output from several sites can provide smooth base-load supply. Indeed, the main company peddling this technology in the UK, Tidal Lagoon PLC, makes this claim.
I built a generation model based on 7 lagoons spread along the English coast in areas with the highest tides. The model shows that the ideology does not work in practice. In fact, UK tidal lagoons will produce more intermittent electricity than any other form of renewable generation providing four spikes separated by four periods of zero production each day. It is often claimed that the predictability of tides is a virtue. This also means we can predict with certainty that this energy source will be a disaster for the public as well as the environment.
This is the key graph:
Figure 10 Summing the generating opportunities shown in Figure 9 creates this picture of tidal lagoon generation for 7 power stations distributed along the best sites on the English coast. The chart is for two days. Rather than showing anything remotely like base-load generation, it shows the most extreme form of intermittency of any renewable generation source with 4 large spikes in generation separated by 4 periods of zero generation each day. By way of comparison, solar has just one spike each day.
Euan’s post is well worth reading in full here.