Wind turbine locations near Cambridge?

This document contains a map and a few thoughts about the potential of locations near to Cambridge for wind power.

Some immediate disclaimers

  1. I work at Cambridge University. But I'm just an individual drawing circles on a map, for fun - I haven't a clue who owns any of this land, and none of this document has anything official to do with the University of Cambridge. I do think it would be fun if Cambridge became a leader in energy systems, reaching the UK's energy targets 15 years early, say.
  2. I haven't done any wind surveys.
  3. Cambridge is not a fantastically windy spot, by British standards, so someone wanting to make highly-profitable windfarms now should probably look elsewhere.

Motivations

Some reasons for encouraging thinking about wind turbines near Cambridge:
  1. Eventually, maybe everyone will have to have wind turbines in their back yard, including people in non-super-windy locations, so why not start planning now?
  2. There has been talk of spending local money on significant works of art, to act as icons, gateways to the East, or Fens, or some such. A sweep of fine wind-turbines might make a nice iconic sculpture, and could have an occasional useful function from time to time.
  3. If an organization wants to have "zero-carbon" electricity, maybe it should actually build some new zero-carbon facilities. Building such facilities locally makes a stronger statement, even if building them in Scotland might have made more power.

A map and an explanation

map of West Cambridge
I've placed three groups of wind turbines on this map.
The collections satisfy a few constraints. First, to avoid shadowing, turbines may not be placed too close to each other. The red circles have radius 200 metres and indicate satisfactory exclusion zones for turbines with a diameter of 82 metres. As you can see from the map of Red Tile wind farm (at the same scale, on the right), real wind farms sometimes have 82-metre-diameter turbines closer to each other than 400 metres. The green circles have a radius of 100 metres. (Red Tile's turbines have a capacity of 2MW each.)
Second, I've slapped tentative 500-metre and 1000-metre exclusion zones around significant collections of buildings. [Some conventions say that a 2000-metre exclusion zone is required around all dwellings. If we went that far then almost no wind farms could be built in England.]
My feeling is that a good place to put wind turbines is alongside motorways. Wind turbines would struggle to be heard over the roar of traffic, so objections to turbines on grounds of sound levels would probably be hard to sustain. Where I have put turbines alongside motorways, I have tended to use a 500-metre exclusion zone rather than 1000-metre.
Of course motorways are not ideal for power production: better for production are hilltops. Therefore the other two sites drawn on this map are on the hills to the north and south of Coton.

Predicted output

Red Tile has a load factor of 25%. Presumably motorway-hugging turbines near Cambridge would not do quite as well - unless perhaps they were mounted on taller towers. Perhaps the hilltop turbines would do better. For simplicity let's run with 25%.

Number
of
turbines
Capacity
(MW)
Average power
produced
(MW)
Highfield11225.5
Madingley Hill482
Motorway Junction 12-13, East side7143.5
Motorway Junction 12-13, West side361.5
Motorway North of Junction 13, East side482
Motorway North of Junction 13, West side7143.5
Total367218

Comparison

The University of Cambridge (not including the Colleges) used 99.5 GWh of electricity in 2006-7. That corresponds to an average power consumption of 11.4 MW. (The university also uses power in other forms, for transport and heating for example. Here's the heating data. The gas and oil consumption of the University was 76 GWh in the same period (average power, 8.7 MW).)

If the University were to erect roughly 30 wind turbines, the average power output could cover its current electricity consumption.

36 such turbines would cost roughly £72 M.

Some frequently asked questions

"Drivers would not be able to safely control their vehicles near such intrusive large turbines"
Drivers who become mesmerized by wind turbines should not be allowed to drive.
"Wind turbines will spoil the view of the countryside from the motorway"
Oh, poor darlings! When they start driving vehicles that don't ruin the tranquility of the countryside, I will be delighted to listen to their concerns.

David MacKay