Swansea Bay tidal lagoon, what is its real cost?

The Swansea Bay tidal lagoon debate tends to focus on its cost. The figure usually quoted is £168/MWh for the feed-in tariff or ‘strike price’ needed to enable it to go ahead. If you were wondering where this number came from, how it was derived, and whether it is still correct, then you’ve come to the right place.

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Rebooting marine energy. One year on.

A year ago I wrote a blog post entitled Rebooting Marine Renewables. Its centrepiece was an analysis of the electricity generated by wave and tidal-current plant in the UK as revealed by ROCs and REGOs. Now seems like a good time to update it by taking a fresh snapshot of the data to see what has happened since then. To keep this article short and sweet please read the original post for background and context. The most relevant part is where the graphs of the data are shown.

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An attempted reconstruction of Tidal Lagoon Power’s ‘New Power Cost League Table’

Tidal Lagoon Plc (TLP) has recently published a document called ‘The New Power Cost League Table’ that compares the cost-effectiveness of different electricity generating technologies according to a new measure they have devised that they call ‘lifetime consumer cost per MWh’. Figure 1 shows the league table.

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Why you shouldn’t use the triangular distribution

The triangular distribution is popular in risk analysis because it seems to naturally embody the idea of ‘three point estimation’, where subjective judgement is used to estimate a minimum, a ‘best guess’ and a maximum value of a variable such as the cost of an item or the time taken to accomplish a task. It looks mathematically simpler than many of the standard distributions and could be regarded as the simplest probability density function that embodies a random variable with a given minimum, mode and maximum. Because of this, you may be tempted to think of it as the distribution that involves fewest assumptions and that it is therefore the one to use when you don’t know what the real distribution is. Its Wikipedia article says ‘… the triangle distribution has been called a “lack of knowledge” distribution’. Although the article gives no reference for this assertion, and I’ve never seen it explicitly stated anywhere else, it sounds plausible and I do think it represents the main reason people use the triangular distribution.

The problem with this idea is that it isn’t true. Read more

…another thing

On rereading my previous post, ‘Rebooting marine renewables’, it occurred to me that it is mostly about why the technologies need to be ‘rebooted’, and not about how it should be done. It was already too long by the time I got to that bit and I just wanted to finish it off as quickly as possible. I think, therefore, that it would be worthwhile expanding on this point, as it’s actually the most important part of the whole thing. Read more

Rebooting marine renewables

Last Monday evening (8 February) I watched an online broadcast of a lecture entitled ‘Marine Renewables – Crossing the Valley of Death’, given at the Institution of Civil Engineers in London by Clare Lavelle, who is head of energy consulting in Scotland for Arup. Before that Clare worked for Pelamis Wave Power and before that for Scottish Power on its wave and tidal projects. Her presentation was very much a statement of the standard wave and tidal narrative that if only the government would spend enough money the technology would succeed. She even name-checked Professor Salter’s conspiracy theory and the one about how the UK lost its world lead in wind energy to the Danes. Read more