Laurence Brahm ("The great green grid", November 28) promotes a massive push by China to invest in so-called "green" energy - including industrial wind energy (IWE) and solar photovoltaics (PV) - to reduce coal use and pollution.
There is globally a crucial need to phase out fossil power and control carbon emissions, but IWE is not part of a sensible solution to climate change. "Free and green" energy is an attractive idea, but, as is being shown worldwide, IWE is not free and not particularly green.
The main problem is that it is not dispatchable ("on demand"), and without efficient, large-scale energy storage (which doesn't exist), can't replace conventional generation from fossil, hydroelectric and nuclear sources.
This isn't "a technological issue that can be addressed through finance and investment", as Brahm says.
Massive green-energy subsidies were legislated in Ontario, Canada. The result, detailed in a 2011 Ontario auditor general report, was a giant boondoggle, with subsidies going to pay other jurisdictions to take excess power when the wind is blowing hard and to generate "windfall" profits for the industry at ratepayers' expense.
More importantly, the billions of dollars squandered on "big wind" did little to reduce carbon emissions.
Wind, and PV, require backup from responsive conventional resources which can come online quickly when the wind dies or the clouds roll in.
In the case of wind, studies have shown that when the conventional fossil fuel generators are kept idling to respond quickly, and are ramped up and down to match the wind's variations, they operate inefficiently and their emissions increase substantially. It is not clear that IWE makes any meaningful dent in carbon emissions.
There are about 1,300 coal-fired power stations on the drawing boards around the globe. The average size of US coal plants is about 240 megawatts.
In order to replace one average coal plant with industrial wind, you need about 720 MW of wind (which generally operates at less than one-third of rated capacity). That's 360 large (2 MW) wind turbines, each sterilising about one sq km area (using Ontario's 550 metre setbacks, which are arguably insufficient). And you still need to keep the coal station running for when the wind dies.
To replace 1,300 coal stations with IWE will require nearly 500,000 square kilometres - the area of Spain. And we will still need to build most of the conventional stations as backup.
Ian Dubin, Kingston, Ontario, Canada