From time to time, new technologies are proposed to help us use even more of Australia’s abundant coal.
Many of these technologies are designed to reduce emissions, either by drying the coal or capturing its emissions as it is burned. Other forms convert coal to cleaner burning fuels, such as synthetic diesel or methane.
For brown coal power stations, use of this technology promises to lower power station CO₂ emission levels to 0.8 or lower (from the 1.2 tonnes of CO2 per MWh put out by a typical brown coal operation). The vision being put forward by government and industry on the back of this promise is that this technology could help to increase our exports. Apart from the promised economic benefit, how real is the promise of lower levels of CO2?
Bodies such as the Intergovernmental Panel on Climate Change (IPCC) have suggested we need to limit atmospheric CO2 concentrations to around 450ppm if we are to avoid dangerous climate change. At current CO2 emission rates, we could reach this level by 2040, or even earlier if the global trend towards coal continues. Since 2000, global coal consumption has increased by 50 per cent, while in China consumption has more than doubled.
Australia is the world’s largest exporter of coal. Government figures say brown coal resources in Victoria are over 400 billion tonnes; 65 billion tonnes is located in the Latrobe Valley with the economically recoverable portion, the reserves of the resource, estimated to be around 33 billion tonnes. If consumed today, Victoria’s coal resources alone could emit sufficient CO2 to reach the IPCC target of 450 ppm. The reserves of the Latrobe Valley alone have the potential to contribute at least two years’ worth of global CO2 emissions.
Because it can take more than 50 years to reduce the CO2 emitted to the atmosphere by a factor of 2 (and around 500 years by a factor of 4), emitting the same amount of CO2 more slowly via lower-emitting technology is likely to make little difference to the climate change problem since it is the total amount in the atmosphere that matters.
Globally, the potential to increase atmospheric CO2 emissions is even greater. Despite the claims of peak oil and declining reserves of fossil fuels, remaining reserves are sufficient to drive atmospheric CO₂ concentrations to unprecedented levels. One estimate of the combined global fossil fuel reserves suggests they are equivalent to almost 100 years supply at the current rate of consumption. When estimates of the total resource base are added, this jumps to more than 1000 years, due primarily to the global resource of black coal.
A further problem we face is the increase in energy consumption which results from population growth. In Victoria, for example, population is expected to grow from 5.6 million to 7.3 million over the next 20 years. To maintain CO2 emission reductions, technological development and its deployment must keep pace with changes in demand. This is made more challenging by the very long operational life of much of this technology.
One benefit of low emission technology is that it might give us the time to further develop the zero-CO₂-emitting energy technologies that we must ultimately use, particularly those based on renewable energy. In a financially constrained world, where giving money to one project means taking it from another, achieving the right balance between these two approaches is no easy task. Many of the newer renewable technologies on offer are yet to be used on a large scale, and much of the technology being proposed for coal, particularly CO2 capture and storage, is still under development, or at best, yet to be demonstrated commercially.
Unless the push to develop cleaner coal is balanced by a greater push to implement zero emission renewable energy technologies, the risks associated with climate change will continue to grow.
Damon Honnery is Associate Professor, Department of Mechanical Engineering at Monash University.