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
-
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.
- I haven't done any wind surveys.
- 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:
- 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?
- 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.
-
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
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)
|
Highfield | 11 | 22 | 5.5 |
Madingley Hill | 4 | 8 | 2 |
Motorway Junction 12-13, East side | 7 | 14 | 3.5 |
Motorway Junction 12-13, West side | 3 | 6 | 1.5 |
Motorway North of Junction 13, East side | 4 | 8 | 2 |
Motorway North of Junction 13, West side | 7 | 14 | 3.5 |
Total | 36 | 72 | 18 |
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