Sunday, 7 July 2013

A Wind Energy vs. Geothermal Energy Case Study: The London Array

On 4th July 2013, Phase 1 of the London Array Offshore Wind Farm, comprising 175 wind turbines and 2 off-shore substations with a capacity of 630 megawatts, was officially inaugurated by the UK Prime Minister

The London Array is an offshore wind farm in the Thames Estuary in the United Kingdom. The project when completed will employ 341 turbines at a cost of around £3,000 million and will be the world's largest offshore wind farm.

Phase 1 and 2 of the project have a nameplate capacity of 1,000 megawatt (MW) and employ 217 turbines. The cost is estimated at £1,800 million. 

Geodynamics, Australia's foremost Geothermal Energy developer estimates that the cost of building one Engineered Geothermal System (EGS) plant generating 50 megawatts, would be in the order of £75 million. If that estimate is accurate, then it would take 20 plants to deliver the 1,000 megawatts of phases 1 and 2, and at £75 million each, the total cost would be in the order of £1,500 million, much less than the £1.800 million estimate for the London Array for the same capacity.

Moreover, EGS plants deliver electricity continuously regardless of the wind (or of the sun) whereas the output of the London Array will depend entirely on the wind. No wind --- no output. And in very high wind conditions, wind turbines need to be shut down!

Engineered Geothermal System

EGS plants require minimum maintenance. What will be the cost of maintaining hundreds of turbines located out at sea? Other than "high", no one knows.

Written by Leonard Berney