How Fast Can Offshore Wind Be Deployed? What Are Its Infrastructure Requirements?

One anti-nuclear argument that’s frequently made is that nuclear is slow to deploy – that renewables can make inroads into carbon production rather faster than can building new nuclear stations. I was recently provoked into taking a look at this, in the context of the UK’s 2020 and 2030 CO2 and Renewables targets, and out plans for nuclear new-build.

The first thing for US readers to understand is that space is at a (relative) premium here in the UK – and hence the options to deploy new onshore wind-farms (the dominant renewables option for us) is limited. We added approximately 500MW of onshore wind in 2009-10 (the last Renewables Obligation reporting period). To all accounts this is likely to slow as resistance to the siting of windfarms increases, and in fact, new accrediations of onshore wind have fallen in each of the last three years (700MW in 2007-8, 600 in 2008-9).

 

On that basis, we’d be well advised to assume at most adding an extra 2500 or so MW by 2020.

Our average capacity factor for onshore wind over recent years has consistently been around the 26% mark. Applying that, we can anticipate average production equivalent to about 650MW.

Let’s assume that EDF get just one reactor up and running in that time (their schedule would have three, so let’s be pessimistic). And, let’s assume it hits the same average capacity factor that Sizewell B has through life, to date – about 88%.

That one reactor gives me 1425 MW average equivalent generation. More than double the amount estimated from onshore wind.

So, rather more progress towards the 2020 goals from the “too little, too late” nuclear option than from wind deployment.

Now, the next thing I’m sure you’ll say is “what about offshore wind”. Well, that’s hardly flying out there – but we’ll ignore that problem too, and simply concentrate on logistics.

We’ll make an easy assumption – we’ll go for a floating system (much faster to deploy than sea-bed mounted systems, especially if we’re assuming moving far offshore). And move far-offshore we will have to, since near-shore potential is ultimately limited.

We’ll assume 5MW units. We’ll assume that the ambition is deploy the same average equivalent generation rate as I’d get from an EPR – 1425 MW. We’ll also assume we’ll beat the current capacity performance for offshore wind in the UK (same source as above) of 27%, by hitting the dizzy heights of 30%.

We’ll need to deploy 950 units.

OK, it’s now 2011. Let’s assume we’re a year in the design, survey etc. for these various schemes, but after that, can push the button at the end of 2012, giving me eight years until the end of 2020.

I need, on average to build and emplace 2.3 5MW units per week. Between friends, let’s call it one per two working days.

Let’s assume a VERY conservative 13 weeks to build the floating platform for each turbine (that’s rather better, btw, than was achieved on much simpler liberty ships in WW2). That’s 65 working days. Allow 5 days at each end for getting the completed unit out and floated, and then the dry-dock cleaned up for the next.

Roughly, I need about 35 working dry docks large enough to build the equivalent of a vessel of several thousand tonnes.

Problem is, there are probably only a couple of hundred such dry-docks worldwide. And about half a dozen in the UK.

So, let’s assume we can build an extra 30 or so in perhaps two years. But, if we need two years, that ups the build rate to about three per week. We’d actually need 40 extra dry docks. Never mind….let’s assume that’s all OK.

But, there’s a problem. I’ve worked offshore, in the north Sea. It’s a b******d of a place for about eight months of the year. Basically, you do the absolute minimum for eight months of the year – don’t even think about trying to emplace a structure other than between March and September, or anything that needs more than about a three-four day period of good weather.

So, we need the ability to manage rather more than two units a week – I need about to emplace 950 units over about six years (having built the dry docks) in about 100 weeks – 700 days. About 1 per day.

Putting an anchored platform for an oil platform in place takes about six weeks at an utter minimum. Lifting the pylon and nacelle for a wind turbine on land needs a week or so, and erecting the blades about the same.

So, about enough anchoring capability to emplace (950*6/100) units at a time – I make it 57. So far as I’m aware, the entire North Sea oil sector supports one or two. We also need to provide floating cranage to life 100 metre length blades onto a 120 metre pylon – about 20 such units. I thinks there’s one or two that service the North Sea oil business.

Quite an expansion, you’ll agree. And that’s just to deliver average generation capacity, in the same time it takes to build a single 1600 MW EPR. One reactor between 2011 and 2020.

So, what’s the actual history of deployment of offshore wind? Well, we’ve yet to emplace a single far-offshore unit. And the record even on nearshore, seabed anchored systems is chequered, to say the least. In 2003, about 50MW. In 2004, much the same. In 2005, about 180MW. In 2006, none. In 2007 about 180MW, and in 2008 back to 90. In 2009-10, we hit about 320 MW. We seem to have nothing due for completion in 2011, then about 2GW is due in 2012, and nothing in 2013. Meaning, it’ll taken us about ten years to install capacity sufficient to give an average ouput equivalent to about half an EPR.

For comparison, France alone built and commissioned about 2 ½ reactors per year through the 70s and 80s. Or, 18 times the rate implicit in the calculations above. The current plans of our three potential nuclear consortia would commission just under 16,000MW from construction of the first unit starting in 2013 to the last starting up in 2025.

I really don’t thing a renewable enthusiast should be making an argument about the slowness of deployment………..

Atomic Insights