Mark Diesendorf: Simple strategies can save our world

Adelaide Advertiser
Friday 8/6/2007 Page: 20

NEITHER coal, with the capture and burial of carbon dioxide, nor nuclear power could make significant contributions to reducing Australia's greenhouse gas emissions before 2025. Yet, urgent action is needed to combat global warming. Fortunately, a mix of efficient energy use, solar hot water, renewable sources of energy and natural gas could achieve large reductions in emissions before 2020.

Australia's biggest single source of greenhouse gas emissions is electricity generation and, in particular, coal-fired power stations. Any strong action to reduce emissions must include an immediate ban on new conventional coal-fired power stations and also on major renovations of old coal stations. So-called "clean coal", a term devised by the coal industry's spin doctors for the capture and underground burial of carbon dioxide, will not be commercially available until well after 2020.

But global warming is accelerating and we must act now to achieve a 30 per cent reduction in Australia's emissions by 2020 and 80 per cent by 2050. We already have the technologies to achieve the first target at a reasonable cost. Sadly, neither the Federal Government nor the Opposition has accepted a reduction target for 2020. Neither has made a commitment to implement policies that could even stop the present growth in emissions. Furthermore, no state government or opposition appears to be serious about ceasing to build dirty coal-fired power stations.

The cheapest and fastest to implement are the myriad technologies and measures for using energy efficiently. In the home, they include: insulation of roof, hot water tanks and (if possible) walls; draught sealing in winter and cross ventilation in summer; gas heating; fluorescent lighting; shading of northern and western windows in summer; fans and evaporative coolers for summer; energy-efficient appliances.

Both energy efficiency and solar hot water are best encouraged by government regulations and standards. To encourage efficient residential energy use, governments should set mandatory energy ratings and energyperformance standards for existing homes as well as new homes.

Wind power, the cheapest of the "new" renewable sources of electricity, could supply 10 per cent of Australia's electricity by 2020 and 20 per cent by 2040. Contrary to the claims of the coal and nuclear industries and their politician supporters, wind energy from several geographically separated sites is moderately reliable and can substitute for some coal power. It may need partial back-up from gas turbines. Since the back-up does not have to be operated frequently, it can be treated as reliability insurance with a low premium.

A slightly more expensive renewable energy source is bioenergy from the combustion of organic residues of existing crops, such as sugar, wheat and plantation forests. Both wind energy and bioenergy need carbon pricing to make them economically competitive with dirty coal power.

The combination of efficient energy use, solar hot water, gas, wind and bioenergy will be much cheaper, much lower in emissions and much faster to implement than the Federal Government's favoured scenario comprising rapid growth in demand, coal with carbon dioxide burial and nuclear power.

We must also be developing those renewable energy technologies that are still expensive, but have huge potential. These are solar electricity, bioenergy from dedicated crops and hot rock geothermal, which together could supply half of Australia's electricity by 2050.


Dr Mark Diesendorf teaches at the Institute of Environmental Studies, University of New South Wales. He was in Adelaide this week to launch his latest book, Greenhouse Solutions with Sustainable Energy.