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Another fairy tale about the levelised cost of renewables

Andrew Montford

I recently described UK government’s latest estimates of levelised cost of renewables as “a fairy-tale”. Well, if Whitehall’s effort was Rumpelstiltskin, then the equivalent document from the International Renewable Energy Agency (IRENA), which appeared yesterday, is Jack and the Beanstalk.

Take the operational costs of windfarms, for example. IRENA claims that it’s difficult get hold of hard data on the subject. This is, not to put too fine a point on it, absolute nonsense. Guys, allow me to introduce you to Companies House, where you will find the audited financial accounts for every UK offshore windfarm and at least half of the onshore ones. Hard data, freely available to download!

For offshore wind, having conveniently overlooked the hard data for another year, IRENA appear to be relying on a 2018 modelling study from the US and a remark in an investor presentation from Orsted (science!). They conclude that opex is in the range £50-100,000 per megawatt of capacity per year.

Figure 1 shows what they might have concluded, had they stumbled upon the cornucopia of data at Companies House.

Offshore wind opex data

The data is divided into cohorts depending on the water depth of the windfarm in question. IRENA does not even allude to opex costs increasing over windfarm lifetimes – a trend that is clear in the data. But whichever way you look at it, their values are around half of anything credible.

It’s a similar story on capacity factors. Figure 2 is IRENA’s graph:

Figure 2: IRENA’s capacity factor graph

A few recent UK offshore windfarms have averaged 46% capacity factor over their first few years, but there is a trend to declining output as time passes. This is clear in Figure 3, which again divides the fleet into cohorts, but this time by size of turbine.

UK offshore wind capacity factor data
Figure 3: UK offshore wind capacity factors

IRENA doesn’t allude this issue, so they appear to be assuming no decline in output over windfarm lifetimes, just as our Whitehall bureaucrats did. As a result, when they look at the effect of opex on overall costs, they conclude that ‘O&M costs per kWh have therefore been falling’, and suggesting that a figure of perhaps £13/MWh ($0.017/kwh) might be expected for European windfarms commissioned in the last five years.

Again, let’s see what effect using some real data has on that value, rather than basing it on throwaway remarks in an industry presentation. I’m not sure I detect anything resembling a decline, let alone anything resembling £13/MWh. It looks as though IRENA’s figures are out by a factor of three.

Offshore wind LCOE data - opex
Figure 4: UK offshore wind – opex element of LCOE

Magic beans are probably the only way we are ever going to see costs this low.

Read GWPF’s study of UK offshore wind costs.