They say that it always pays to read the small print.
And, when it comes to anything to do with renewable energy, it is also wise to read between the lines.
For instance, the other day, I came across this puff piece about the the Celtic Sea floating wind project on the Pembrokeshire Herald’s Facebook page:
“The UK Government-backed plans could generate up to 4.5 gigawatts of electricity—enough to power more than four million homes—while creating over 5,000 skilled jobs and attracting billions of pounds in investment.”
The word could is doing the heavy lifting here because the 4.5 gigawatts refers to the maximum output of the whole array when running flat out, without letting on that it will have a capacity factor of somewhere between 40% – 50% and will produce nothing at all in still conditions.
So it would be more accurate to say that the Celtic Sea scheme will generate electricity equal to the consumption of 2 million homes, but that it will require back-up from a dispatchable source such as gas or nuclear during calm weather.
The 4.5 gigawatts (4,500 megawatts) capacity scheme will require 300 15 Mw Vestas V236-15.0 MW turbines.
This project is supposed to be up and running in time to meet the government’s 2030 net zero target, and the mathematicians among you will already have worked out that, as that is just 260 weeks away, it will require the erection of more than one of these 200+ metre monsters every week.
Indeed, it is difficult to imagine the scale of these machines with each blade longer than a football field.
Vestas’ own website gives the picture:
The turbine model V236-15.0 MW from Vestas features a capacity of 15 MW and a 236-meter diameter rotor with hub height of about 145 meter, highest tip of 263 meter.
And we are being asked to believe they can manufacture, transport to site and erect one of these leviathans on a weekly basis.
Having shone a light on the output of these machines, we can now turn our attention to the promised jobs and investment.
The blurb doesn’t make it clear whether these 5,000 jobs are permanent, or just for the construction phase, but as this is close to fifty times the number required to man Pembroke Power Station which has a similar output, we can assume it is the latter.
It should always be remembered that jobs are a cost and paying all those additional people to generate the same amount of power would seem like a rather expensive business.
Unfortunately, the size of investment which is said to be billions of pounds is also rather vague.
However, as billions implies that it will be at least two, we can do some preliminary sums on that basis.
Given an 8% rate of return + a 2% maintenance cost on a two billion pound investment would carry finance costs of £200 million a year, and, given a lifetime of 30 years, the amortisation of these assets would cost another £66 million annually and that’s before we get our teeth into the cost of decommissioning all this kit at the end of its useful life.
And, of course, if billions means something more than two, the sums will need to be adjusted accordingly.
And, if it was 5,000 permanent jobs at £40,000 a shot, that would be another £200 million and, as they say, before you know it you are talking serious money.
All this helps explain one of the abiding mysteries about electricity generation: why is it that the countries with the highest proportion of “free” renewables in the mix also have the highest electricity prices?
Energy analyst David Turver claims the answer lies in the huge capital cost of harvesting this “free” energy.
According to Turver we spend £6-8 billion annually on purchasing gas for electricity generation and that is dwarfed by the financing costs on the circa £250 billion capital expenditure needed to replace gas-fired generation with wind turbines and the upgraded grid to handle their output.
It is easy to fall into the trap of thinking that wind and solar are free while forgetting that gas and coal, themselves, cost nothing. The cost is in harvesting these “free” resources and building the devices that turn them into electricity. And, as the energy density of fossil fuels is so much higher than that of wind and solar, the equipment required to harvest them is correspondingly less expensive.
Tangled up as it is with the Second Law of Thermodynamics, energy density is one of the most difficult concepts around.
One way to think about it is that a cupful of petrol will be enough to propel your car up to the top of Dredgeman’s Hill. Once up there you have a ton weight on wheels that can be run back down again to do more or less the same amount of work that the cupful of petrol did in the first place. Or, to put it another way, chemical bonds have much greater energy density than gravity.
Alternatively, you can consider the relative value of a kilo bag of sugar in your kitchen cupboard and ten tons of the stuff evenly spread over a ten acre field.
With all that in mind, we can, perhaps take a more realistic view of the words of Secretary of State for Wales Jo Stevens MP.
According to the press release, Ms Stevens said:
“Floating wind technology is at the forefront of the green energy revolution, offering an exciting opportunity for Wales to lead the way in developing this innovative technology. This is an incredible leap forward for renewable energy and a major economic opportunity for south and west Wales.”
Of course, there is nothing particularly innovative about any of this technology, but, even if it turns out to be a complete turkey, the inward investment will provide a much-needed boost to the Pembrokeshire economy.