12.4 TECHNOLOGY

12.4 TECHNOLOGY

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TECHNOLOGY

Boundary Dam pioneers CCS for power plants

By Tony Zhang, Senior Adviser – Carbon Capture, Global CCS Institute

Victoria has significant brown coal reserves with the potential to supply energy to Victoria for centuries to come. Brown coal has been providing power for Victoria for almost a century and still provides the majority of Victorian base load power, with an installed capacity of around 6.75GW.

However, brown coal being an immature coal and close to the surface, contains large amounts of water, often in the range of 48–70 per cent by weight. To quote a veteran boiler engineer in Latrobe Valley, ‘we need to burn the coal to dry the coal to burn the coal.’

Extra energy is required to vaporize the water contained in brown coal. As such, the brown coal power generation efficiency is often comparatively low, often in the range from 20–35 per cent. Such low thermal efficiency leads to a high carbon footprint.

Brown coal power stations generally emit more than 1 tonne CO2 per MWh. Owners of brown coal power stations have invested significantly to maintain and to upgrade the boilers, turbines and other ancillary systems. For example, the Hazelwood Power Station has in recent years completed the upgrade of two units, including installing two new generation turbines, which increases the efficiency of the two units significantly. These power stations, with the new upgrades, can be kept operational for a long time.

Carbon capture and storage (CCS) has the scale and application to enable the power sector to produce base load with significantly reduced emissions. The IPCC Fifth Assessment Synthesis Report, released in November 2014, notes that without CCS the cost of meeting global climate goal could be nearly 140 per cent higher (compared to scenarios with CCS), indicating CCS is an important component of a portfolio of technologies to combat climate change.

What many don’t know is that CCS is now operational at large-scale in the power sector. The world’s first application


of CCS at large-scale on a power station went live at SaskPower’s Boundary Dam facility in Canada in October this year. This project will capture one million tonnes of CO2 per annum.

Two more CCS projects in the power sector are under construction in the United States and are planned to commence operation in 2016 – at the Kemper County Energy Facility in Mississippi and the Petra Nova Carbon Capture Project in Texas. The Kemper County facility will capture around three million tonnes of CO2 per year, Petra Nova around 1.4 million tonnes per annum.

The Boundary Dam plant uses lignite (brown coal) as its fuel source, as will the Kemper County facility. The fact that the first two CCS projects to become operational in the power sector happen to be based on brown coal is based on a range of factors, an important consideration being the commercial competitiveness of the brown coal feedstock.

Continued deployment of large scale projects will improve efficiency and cost of CCS technology. We are already seeing this in action, with CCS demonstration in the power sector gaining valuable design, construction and operational experience by ‘learning by doing’.

Being a first-of-a-kind project, Boundary Dam’s operator, SaskPower, has stated that a capital cost reduction of up to 30 per cent is achievable for its next CCS project. The world’s power industry is taking a close interest, in particular how the savings, commissioning procedures and standard operations can be applied to projects elsewhere.




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