Can renewables re-power Australia?

Monday, September 7, 2009

"Forget 'alternative' energy — it can't work!" That — and in almost those exact words — was among the messages of an article published in the Rupert Murdoch-owned Weekend Australian on August 8 by journalist Terry McCrann.

Wind power in particular, McCrann assured us, was "useless". And the proof? "In a brief but utterly devastating analysis", McCrann said, "Andrew Miskelly and Tom Quirk tracked the power output of all the now quite substantial wind farms in South Australia, Victoria, NSW and Tasmania for every minute of June. The simply devastating conclusion: when the wind don't blow, it don't blow everywhere at the same time.

"This utterly shreds the claim that if you build enough wind farms nationally the wind will be blowing somewhere. You have to keep fully equivalent coal power up and running, not just when the wind is not blowing, but all the time."

Actually, the above-noted study does nothing to disprove the fact — well demonstrated by studies in the US and Spain — that widely dispersed wind farms with modest back-up from other energy sources can provide round-the-clock "base load" power.

Data collected by Miskelly and Quirk during June 2009 showed the total output of 11 Australian wind farms was close to zero on about six occasions, for a total of about 100 hours.

However, the electricity measured was mostly from large wind farms grouped in a relatively small area in western Victoria and south-eastern South Australia — not far apart and subject to different wind conditions. There was only a small input from NSW wind farms in the study.

Meanwhile, McCrann's claim that wind power needs to be matched at all times by coal-fired power proves just one thing: he knows nothing about energy generation.

When the wind doesn't blow, there are various options for taking up the slack. One is to use hydropower, which can be brought into operation almost instantly. For the most part though, Australian grid controllers prevent outages by using gas-fired power as back-up.

This reserve equipment has to be in place whether you use wind or not, since fossil-fuelled plants suffer breakdowns from time to time. Typically, coal-fired plants are shut down for repairs and maintenance about 10% of the time. This compares with less than 2% for modern wind turbines.

Energy authorities, of course, know perfectly well that a large high-pressure system can bring relatively light winds simultaneously to most of south-eastern Australia. The resulting lulls in wind power can usually be forecast days in advance. That's time enough to take countermeasures — including, in extreme cases, temporarily firing up mothballed coal-burning plants.

However, the most obvious point ignored by the Australian is that wind power is not the only form of renewable energy — it's just the one that's now most developed and cheapest.

Future electrical grids will be much more diversified. Lulls in one renewable energy source can be made up by robust output from others.

Consider wave power. In the strong, constant swells of the Southern Ocean, Australia is reckoned to have the world's largest and most consistent wave energy resource. Along lengthy stretches of Australia's southern coastline, wave heights rarely fall below one metre. That is base-load energy waiting to be tapped.

After a decade of development at Fremantle in Western Australia, Carnegie Corporation's CETO wave technology is now at the pre-commercial stage. Finance is being sought for a demonstration wave farm and negotiations are under way for test sites.

CETO uses the action of waves on submerged buoys to work pistons anchored to the seabed. High-pressure seawater is piped ashore where it powers turbines that generate electricity.

Costs are predicted to be similar to those for wind power at good sites. When demand for electricity is low, the high pressure can be used to desalinate seawater.

Still more revolutionary, arguably, is solar thermal technology that has been developed over more than 30 years by engineers and scientists at the Australian National University (ANU) in Canberra.

Solar and wind power have long been recognised as complementary to one another. When winds during the day are light, the odds are high that the sun will be shining brightly.

Near Whyalla in South Australia, a plant is being built that will further test the ANU designs.

The installation will feature large solar mirrors, able to track the sun and concentrate its rays up to 2000 times. Four 500-square-metre "Big Dishes" will create maximum temperatures of more than 2000ºC, several times hotter than advanced fossil-fuel generating plants.

As well as opening new horizons for solar electricity generation, the equipment has potential for use in ultra-high-temperature industrial processes.

ANU's technology also promises to overcome the dual scourges of solar power — nightfall and cloudy weather. The intense heat of the Big Dishes will be used to heat ammonia to separate it into nitrogen and hydrogen. These two gases can be stored for as long as needed and retain most of the original energy.

Solar power will thus be turned into gas-fired power — available at any time.

The initial stage of the Whyalla project, to cost $15 million, will start operating in mid-2010. About $350 million will then be sought to build a 600-dish, 80 megawatt solar thermal plant.

Estimated electricity costs for the new system have not been released. But the technology appears to have important advantages compared with competing solar-thermal power systems — whose costs are predicted eventually to undercut those of fossil fuels.

The Big Dishes have been designed for cheap mass production and the ammonia process is described as suitable for large-scale solar fields of 500 megawatts or more. The potential for using the dishes with other high-temperature processes could also be an important factor helping to cut costs.

Not only might this world-leading technology allow Australia's vast solar power resource to be used to replace fossil fuels, but it could also become a big export earner within a few years. Certainly, it seems a better investment than "clean coal", which is to receive hundreds of millions of dollars in federal funding.

Curiously, ANU's Big Dishes remain little-known, even among renewable energy enthusiasts. The main Murdoch publication in South Australia, the Adelaide Advertiser, has referred to them in only a few small, cursory reports.

The Australian, so far as this writer can tell, has published nothing. But considering the close ties between the Murdoch empire and the coal industry chiefs, that is not so surprising.