Chris de Freitas: Coal's the best answer to electricity shortages

COMMENT

For supporters of renewable energy, the holy grail of producing the bulk of the country's electricity needs from so-called clean sources seemed like an impossible dream this week when Meridian Energy scrapped the $1.2 billion Waitaki River hydro scheme.

The failure of Meridian's Project Aqua and lack of legislative support for it is more proof that the Government has no viable policy for ensuring available supplies of energy. In fact, it has clearly decided to limit its options for security of supply.

We are still some way from a full-blown energy crisis but time is eating away its margin of comfort. Our great reliance on natural gas and its looming shortage will drive energy prices steadily upwards.

At the same time, the Government is facing a moratorium on new coal-fired electricity generation, so that New Zealand can meet its commitments to the Kyoto Protocol, which some people believe is not necessary.

Nuclear power is off the agenda for the time being, so we are left with solar and wind. But are these realistic options?

For remote communities, solar and wind power are now more economic than small fuel generators, or the extension of the electricity grid or gas mains at great cost. So there are some niche markets, the best examples of which are wind-powered water pumps to extract water from wells to fill remote drinking troughs for livestock or the water tanks of isolated homesteads. But that is different from use for substantial power generation.

The reason is simply that wind power is uneconomic. For example, British energy critic Dr Richard Courtney points out that the price of wind-powered electricity in Britain is about £50/MWh, compared to market rates for other electricity sources of about £15/MWh.

The results from experimental wind farms along the Pacific coast of the United States are further evidence. Originally these were connected to the larger power networks but they contributed only a limited amount of power and were not cost-effective. Most eventually fell silent as tax deductions ran out and subsidies died away.

Wind farms generate electricity only when they are working, which is only when the wind is not too strong or too weak. But electricity is needed all the time and conventional power stations must provide this when the wind farms are not operating.

Thermal power stations cannot simply be switched on and off. They use the heat from burning coal, oil or gas to superheat the steam from boiling water that is fed to turbines which produce electricity. Given the time to gear up, back-up power stations are operated on working stand-by so they can immediately provide electricity as demand for power increases, or if power from other sources fails.

Dr Courtney says that because of this the use of wind farms does not replace thermal power stations. It requires these stations to operate on spinning stand-by so they can immediately provide electricity when the wind farms stop because the wind speed has changed too much.

Simply, most wind farms provide additional fluctuation to electricity supply, and additional back-up is needed to compensate. Each wind farm increases the risk of supply failure by the amount of its output.

Another problem is that wind farms are environmentally unfriendly. By default they are very visible and excessively noisy. Each wind tower needs a large concrete foundation, a complex of numerous towers and a network of service roads for maintenance. And the level of bird kill from the whirling blades of the turbines is astronomical.

Late last year, the Washington Post reported from California: "The freezers at the US Fish and Wildlife Department in the Sacramento Valley are overflowing with the decapitated and mangled bodies of golden eagles, kestrels and red-tailed hawks, victims of the whirling blades of wind turbines. Scientists estimate as many as 44,000 birds have been killed over the past two decades by these towering machines in the Altamont Pass, east of San Francisco."

Offshore wind farms have similar environmental effects, and the British Government has stipulated these must be a minimum of 8km offshore and, in some cases, as much as 11km from land.

Faced with declining reserves of natural gas, it is now more important than ever that the Government look for ways to promote plentiful and diversified sources of domestic energy. While we search for cost-competitive renewable energy resources, our most obvious natural strength is abundant coal.

The Government must promote development of electricity production from clean coal technologies. We cannot, as a nation, walk away from such an obvious choice for energy self-reliance and should take all reasonable measures to advance its use.

* Chris de Freitas is an associate professor in geography and environmental science at Auckland University.


Electricity