Sunday, June 28, 2009

Visualizing wind farms for Cambridge University

I thought it would be a fun exercise to see, on a map, whether we could imagine powering the University of Cambridge from local wind turbines. The University's average electricity consumption is 11.4 MW, and its gas and oil consumption is 8.7 MW. (That's the University departments and offices only, not the colleges.) If we switched our heating over to heat pumps and insulated all the buildings, maybe the total consumption could be covered by 16 MW of electricity. Probably about 72 MW of wind capacity would be required to produce 16 MW on average. That's about 36 big wind turbines of the standard 2-MW size in the photo above, which shows Red Tile wind farm.
This web page contains my notes and the map, which is reproduced below. [Please click on the map to see the whole thing.]

The left side of the map shows West Cambridge, with locations for wind turbines shown by the green and red circles. Exclusion zones are indicated by blue circles. I've assumed that turbines could be put alongside the motorway and that motorway noise would dwarf the turbine noise, so that smaller exclusion zones are appropriate near motorways.
The right hand side of the map shows the Red Tile wind farm to the same scale.
I don't know who owns any of this land, nor have I done any wind surveys, so no-one should take this map seriously.
It would cost roughly £70 million to put up these turbines.
If people don't like the idea of having iconic wind turbines ruining the tranquility of the M11, another option would be for the University to buy a 1.6% share of a new nuclear power station. That might cost £32 million or so.


Unknown said...

So what do you make of this?

David MacKay FRS said...

Hi Tom, Of course the paper reported in the Telegraph is correct. It is saying nothing new - as I said in my book, if you completely cover the countryside of Britain with wind farms then you could get more power than our average power consumption. Obviously if Britain "can live on wind" in this sense then the whole world can too (on average), since the whole world has lower population density than Britain. So now it's just a question of everyone getting real and deciding what fraction of countryside we are actually willing to cover with wind farms, and how we are going to pay for them.
The numbers in that paper, by the way, completely agree with those in my book. They imagine that wind farms would deliver a peak power per unit area of about 8 W per m2, and 4 W/m2 in mountains. Once you take load factor into account, you're down in the 2-3 W/m2 range.

Unknown said...

Thanks for your helpful and detailed reply, David. I have bought your book, but have so far omitted to read it - funny how that impedes the process of learning. Time to get reading... 8-)

osiris87 said...

Well you're a Trinity graduate - perhaps you could persuade Sir Martin to throw some of the college's endowment at this idea. It would be great for any student to be able to boast that their college has its own wind farm.

Luis Enrique said...

Dear Prof MacKay,

I thought you might be interested in this - a just released proposal for global climate policy, from a Harvard Econ who worked on Kyoto for Clinton.

(you might like this too, from the same stable)

Milan said...

The University of British Columbia is a holding a contest where people submit plans to make the university self-sufficient in energy and water use. It looks like quite a challenge.

TucsonAustrian said...

What happens if the wind stops blowing for a while? Backup power must come from somewhere.

I have often seen the giant windfarm near Palm Springs be dead quiet for hours (my mother lives there)

Wind power is a fill-in, but can't be relied upon consistently.

Dream on.

David MacKay FRS said...

"What happens if the wind stops blowing for a while?"
You know, I've been thinking about energy for four years, and that thought never occurred to me! And no-one ever mentioned it before.
Seriously, why don't you read the book? The chapter called "Fluctuations and storage" starts on page 186. Enjoy! David

DanH said...

Generally nice thinking. Three things to watch out for:

- Recent experience with Linton Wind Farm suggests that proposing to put turbines within a kilometre or so of an SSSI turns the public mood quite decisively against you. Some of your sites on the east side of the M11 are quite close to Traveller's Rest Pit - which, ironically, is an SSSI because it contains a detailed geological record of Quaternary climate change.

- Most, if not all, of your sites, are on the territory of a different planning authority from most of the University. That planning authority has 120000 citizens of its own (including, IIRC, your good self) to keep supplied with (hopefully sustainable) energy. You may need to think about how "local" is local enough.

- Current draft UK legislation on emissions reduction, under the title "carbon reduction commitment", proposes to treat the University and the Colleges as a single organization. "University departments and offices only, not the colleges" may not be a relevant categorization.

Milan said...

For those uncertain about the abbreviation, an 'SSSI' is apparently a Site of Special Scientific Interest.

Andrew Smith-Gibbs said...

£32m to provide 16MW mean power from a new nuke? Given a 90% load factor, that's £1.8m/MW for nuclear. Sadly, that really doesn't match real world prices - which are more like £10m/MW. For 16MW mean power @ 90% load, that's £178m/MW over forty years, whereas wind turbines would cost £140m (2x£70m over forty years), even using the low capacity factor you've used, and assuming zero end-of-life value for the turbines (whereas, in reality, over 90% of the material could be sold for reuse).

Florida Power & Light are spending US$17bn just to construct 2.2GW, which works out around £4.8m per MW. Decommissioning costs in Britain are currently running at £73bn and rising, for what, around 14GW of nuclear? So that's another £5.2m/MW. But that's only an interim estimate, as we still haven't worked out what to do with that waste. And then there's all the fuel and operational costs.

There are no significant insurance costs, obviously, because no one in the world will insure against a meltdown. Is it really worth paying an extra £38m+ just to have all that fun with nukes, and all their unnecessary risks and environmental damage?

And, as we've discussed before, nuclear would have much higher greenhouse gas emissions than wind, too. So, nuclear fails on cost, climate change, and strategic risks. Oh, and of course, whereas the wind turbines could be built and operational within 3 years, and a 9 month payback time to recover the energy used in construction; nuclear would take 10 years to build, 2 years or so after commissioning to get up to peak capacity, and 5-7 years to pay back its intrinsic energy cost.

TucsonAustrian, as you're interested in how grids can manage perfectly well with a lot of power coming from wind turbines, check out the book Renewable Electricity and the Grid - in short, the variability of wind is perfectly manageable technically and economically.

Brian O' Hanlon said...

Talking about visualisation of things quite large, the Greenpeace publication on solar energy is definitely worth a download and a good look.

For instance, South Africa whats to replace 2 no. coal fired plants with renewable generation by 2013. Basically a nice round target figure of 10,000 gwh in the next 4 years produced using renewables.

I was looking at the energy breakdown for South Africa and comparing it to Ireland. It is very different. The sheer vastness of South Africa tells in the fact the residential energy consumption doesn't take over so much of the pie chart as it does in Ireland. The industrial energy usage in South Africa is huge. Transportation, it being a huge country again is very significant. Agriculture too accounts for 4 per cent compared with only 1 per cent in Ireland.

DanH said...

Investments in renewable (or, more generally, decarbonized) energy need capital funding. Hence, it's interesting that paragaraphs 18-21 of the recent annual report of the University Board of Scrutiny suggest that this is an exceptionally favourable time for the University to borrow money through bond issues.

DanH said...

Upthread, I said

Most, if not all, of your sites, are on the territory of a different planning authority from most of the University. That planning authority has 120000 citizens of its own (including, IIRC, your good self) to keep supplied with (hopefully sustainable) energy. You may need to think about how "local" is local enough.

I notice that this has just started to become a live issue between the two planning authorities. Fortunately, all quite amicable at the moment. Let's hope it stays that way.

mechovator said...

Like this discussion. Learned several aspects related to wind turbines including technical as well as financial. Are the designs of wind turbines changing, or is this technology already mature? What are the current research topics at CU related to design of wind turbine?

Helen Highwater said...

This article about a wind farm in southern England reminds me of the following. If one googles "EEA map wind speed at hub height" one finds an interesting document called Europe’s onshore and offshore wind energy potential. About a fifth of the way down, map 2.2 (average wind speed 2000-2005 at hub height 80m onshore) shows surprisingly that the home counties do very well, better than most of the rest of the UK. Even the upland areas don't do that well. Further evidence is that the only proper wind farm in the regions encompassing London and south east of England is Little Cheyne Court near Dungeness nuclear station, and it achieves 28% load factor, same as the Scottish long term average.
At the same time, we’re told that Scotland is the Saudia Arabia of Renewables and that is why we are getting more Wind capacity per unit land area compared to further south .
But considering the information in paragraph 1, and that the southern parts of Britain already have a good grid infrastructure and have large population centres nearby, shouldn’t they be building wind farms in Surrey and Sussex instead of Sutherland? After all, the southern parts of Britain from the Midlands southwards has 40% of the land area but only 19% of the wind turbines. They also consume 62% of the electricity. Also, excluding the very biggest cities, electricity use per capita generally increases as you move further south in their area despite the warmer climate. And it might save yet another Beauly-Denny line. So, shouldn’t our southern neighbours be doing their bit?