Australasian Science: Australia's authority on science since 1938

Burying CO2 Is Cool

By Olivia Kember

Carbon capture and storage is a necessary component of any realistic effort to control global warming.

Using technologies to capture carbon dioxide produced by power stations and industries and pump it back underground features prominently in scenarios for achieving the global goal of avoiding warming above 2°C – yet it remains deeply contentious.

In many of these scenarios, carbon capture and storage (CCS) needs to be applied not just to coal and gas power but to industrial processes like cement production and even bio-energy generation. Bio-energy with CCS (bio-CCS) isn’t just carbon-neutral, it could be carbon-negative. Applying CCS as biomass is combusted or fermented to produce energy largely removes from the carbon cycle the carbon dioxide that the biomass absorbed from the atmosphere.

A recent study by the Potsdam Institute found that without bio-CCS, achieving the 2°C goal becomes twice as expensive, and limiting global temperature rise to 1.5°C becomes impossible. If emissions slightly overshoot our targets, or the climate turns out to be more sensitive than anticipated, bio-CCS can help us recover.

However, CCS is regarded with suspicion by some green groups and fossil fuel industries. Some environmentalists oppose public financing for CCS but support policies that could drive demand for CCS, such as prices and limits on emissions. Fossil fuel representatives welcome public money for research but campaign against policies that would encourage CCS deployment.

Oddly, both sides sometimes agree that CCS is not yet viable, but every aspect of the technology has been proven. There are now twelve operational large-scale CCS projects globally, with a further nine due to open by 2016.

The high cost of CCS is also often cited, but further development and deployment will bring costs down. After trialling CCS on one unit of its Boundary Dam coal power station in Saskatchewan, Canadian utility SaskPower plans to fit CCS to other units. It estimates the next unit will cost 30% less to construct and 20% less to run.

However, these steps forward are nowhere near enough. In a recent report the International Energy Agency warned that “the rate of capture and storage must increase by two orders of magnitude in the next decade” to be on track to the 2°C goal. Without CCS, recently-built power stations would have to close and emerging economies would have to abandon coal altogether – both very expensive and difficult to do. In addition, many industries such as cement production have no viable alternatives to make deep cuts in emissions.

For bio-CCS, perhaps the biggest challenge is to ensure that production of biomass for energy neither undermines food production nor encourages detrimental land-use change. One way is to explore the production of “advanced” feedstocks, such as algae, pongamia and coppicing species.

As one of the developed nations most vulnerable to climate change, it is strongly in Australia’s national interest to advance critical emission reduction technologies. Our fossil resources also provide us with a strong incentive to encourage the roll-out of CCS. Moreover, we have an abundant supply of agricultural residues (one of the more sustainable biomass sources) and a large natural geological storage potential both on and offshore.

Recent modelling by The Climate Institute and Jacobs SKM found that by 2050 the use of bio-CCS in Australian electricity production could remove and displace 63 million tonnes of CO2 per year (equivalent to 1.5 times the emissions from Australia’s current cars), all using current levels of waste biomass. If the technology starts coming online commercially from about 2030, the cumulative savings total 780 million tonnes from now to 2050.

A big question remains over whether the level of bioenergy needed could be produced in a socially and ecologically sustainable manner. These risks don’t mean we shouldn’t consider the potential of bio-CCS or other carbon-removal technologies; they mean we need to work out how to do it properly.

To get there from here we need targeted investment in developing bioenergy and CCS technologies. We also need a reliable reward system for carbon removal, and the best such system remains – despite all the political hot air – a strong, stable carbon price.

Olivia Kember is National Policy and Research Manager at The Climate Institute.