See original Daily Telegraph article at:
(Obviously a) ignoring mismatches between supply and demand whic h can be dealt with in a variety of proven ways
and b) obviously you wouldn’t in fact build them in one square, (this is just for illustration) but rather in lines only about 2 deep.
A 5 MW turbine rotor diameter is 126m ( from the Repower website http://www.repower.de/index.php?id=12&L=1 )
According to Martin Alder, Optimum Energy, a wind farm owner and developer:
Across wind turbine spacing = 3 x dia (Assume tower to tower)
Down wind turbine spacing = 5 x dia
According to Colin Palmer, of Wind Prospect, a leading wind farm developer, load factors of 30 – 35% onshore, and 40% offshore are readilly achievalbe.
So assume 33%.
Take a 70 mile by 70 mile square. This equals 112 km by 112 km
So downwind, turbine spacing (tower to tower) will be 126 x 3 = 378m. Thus in 70 miles / 112 km we can accommodate (112 x 1000 / 378 ) +1 = 297.3 towers (allowing half blade length to protrude out of area at edges).
Similarly, cross wind, we need 5 x 126 = 630 m. Thus in 70 miles / 112 km we can accommodate (112 x 1000 /630) +1 = 178.8 towers (again allowing half blade length to protrude out of area at edges).
Thus a 70 mile by 70 mile square can accommodate 297.3 x 178.8 = 53,157 turbines..
At 5 MW each, these will generate at peak 265.7 GW.
Assuming reasonable sites and a 1/3 , 33% load factor, this will generate on average 79.73 GW.
Note: The issue of matching a variable supply to a varying demand, and what do do when there is no wind, is dealt with in numerous articles on the Claverton Web Site, and this compressed note from Dr Mark Barrett – it is a an issue that can be dealt with at an affordable price with perfectly well known and exisitng methods:
from Dr Mark Barrett:
” Matching demand and supply can be done with:
1. Demand interruption, fuel switching
2. Storage heat/elec /chemical in fridges, EVs, HW tanks, CHP heat,
pumped storage, existing hydro, chemical fuels etc etc.
3. Dispatchable renewable (biomass, hydro…) and fossil
4. Transmission (ie European Supergrid) connecting large geographic areas, as a diversifier and facilitator
Route is to develop 1-4 on least cost path. Retain existing fossil and build more if
necessary (e.g. open cycle gas turbines). but maybe not least cost.
This is discussed and modelled in my work and Gregor Czisch’s, though there are
many details to resolve and the 2050 system is impossible to predict, not
Renewable electricity system: Feasibility of a high renewable electricity
Barrett, M. 2007, A Renewable Electricity System for the UK. In Renewable
Energy and the Grid: The Challenge of Variability, Boyle, G., London:
Earthscan. ISBN-13: 978-1-84407-418-1 (hardback).
Dr Mark Barrett, Principal RCUK Academic Research Fellow
Energy Institute, University College London
Room 227, Wilkins Building, North Cloister
Gower St, London WC1E 6BT
Site : www.bartlett.ucl.ac.uk/markbarrett/Index.html
Tel UCL: +44 (0)20 7679 2593
Tel Mobile: +44 (0)7837 338297
Tel Home: +44 (0)1206 542596
Skype: MarkAlexBarrett (Mark Barrett)
Dr. Gregor Czisch has intesnively studied integrating large scale wind generation into Europe:
Dissertation: Szenarien zur zukünftigen Stromversorgung
Low Cost but Totally Renewable Electricity Supply ..
Effects of Large-Scale Distribution of Wind Energy ..
Global Renewable Energy Potential and Approaches to its Use