On Renewables Without the Hot Air Estimnates of Off-Shore Wind Generation

[danieldwilliam]

Further to a converation elsewhere I've re-skimmed some Renewables Without the Hot Air estimnates on offshore wind. WOTHA estimate of usage is 195 kwh per person per day. Estimate of shallow offshore wind production is 1 kwh per person per day and deep (25-50m) offshore production at double that, 32 kwh /day / person. Total is 48 kwh /d/p.

Shallow area 40,000 km2 with energy denisity of 3W / m2. 1/3rd of shallow waters to be used. Some vague mumbling about shipping and fishing getting int he way.

Based his assumptionson 3MW turbines. 7MW seems standard now. I reckon we'll see 10-12 as the standard in a few years. Not sure what that does to the energy density by area but it can't hurt.

I've always thought his modelling of the economics was niave in that it did not allow for things to become feasible once the cost started falling. When something becomes cheaper to do than the alternatives it all gets done.

I reckon you could double the estimated output by increasing the turbine size, tower size and increasing the area. That gets you to 98 kwh /d/p.

Use of floating turbines in 50m+ deep waters should get you to double that 98 kwh /d/p or about 200 kwh per person per day.

Building all of this is not a trivial economic or engineering task. I think building solar PV in Morocco and shipping the power north will prove cheaper and quicker.

Comments

[andrewducker]

Thank you!

So the figures look much better than he thought because the technology has greatly improved.

(Shame he's not about to update the book)

[danieldwilliam]

I think he would consider me to be too optimistic. However, the tech has moved on in terms of the size of the turbines and towers.

I'm not sure what exactly was driving his decision to only include 1/3rd of the available sea area. Shipping lanes and fishing but I don't think there was much thought beyond "hey, shipping and fishing will need some space".

The real change in my mind is the floating offshore wind technology at eg Hywind.

My model for these things is that new ways of doing things start costing eye-watering multiples of the alternatives. With a bit of development you might start seeing a way to getting the cost down to a mere order of magnitude more. If there are not any fundamental barriers implicit in the physics the cost reduction becomes a function of learning curve effects, scale economies the interactions with adjacecent enabling technology. Once you get yourself on the cost reduction path you are likely to come out at as cheaper than the existing alternative over time.

So key barriers are fundamental barriers in the physics and whether the investments required by earlier adopters to get the technology on a cost reduction path are ever going to be worth it.

CCS for me fails the two tests because it's difficult to see a way of burning fossil fuels and sequestering the carbon that releases more usable energy than just sourcing it from solar PV and even if you could solar PV is almost certainly going to chase you down the cost curve.

Off-shore floating wind passes the first test. There doesn't seem to be a physical limits that stop us building the turbines we would want. Looks like the technology is on a beneficial glide path for costs.

I still think solar PV and big cables will end up being cheaper.

It is a shame he's not around to update the book. I'd be interested to see if his fundamental thinking changed in light of the different economics.

[hilarita]

There's probably also some assumptions about leaving space for birds and not disrupting too much of the maritime environment.

[danieldwilliam]

He talks a bit about birds but I didn't notice an explicit assumption about them.

But he's generally taken quite a conservative line on assumptions -which is fair enough given that others have probably taken too optimistic a set of assumptions.