What is Alcoa doing about Climate Change?
Alcoa is committed to working constructively with the Australian Government to ensure the issues and challenges faced by the alumina and aluminium industries, under a price on carbon emissions, are well understood. We continue to consult with all our stakeholders, about these challenges, including the community, our workforce, business organisations and relevant unions.
In Australia, Alcoa is reducing greenhouse gas emissions through energy efficiency, productivity improvements and new technology. In 2003, we achieved our target of reducing global direct greenhouse gas emissions by 25% from a base year of 1990. Since 2003, we have further reduced global direct greenhouse gas emissions to 44% below 1990 levels.
Alcoa has made significant efficiency gains in both direct and total emissions per tonne of product (GHG intensity). Direct greenhouse gas emissions are those released directly, while indirect emissions are those that result from power stations that supply energy to be used in production or manufacturing, such as a smelter. Both direct and indirect emissions are added to calculate total greenhouse gas emissions.
Alcoa has reduced direct greenhouse emissions per tonne of production:
- aluminium smelters – by 65% from 1990 levels
- alumina refineries – by 21% from 1990 levels
- aluminium rolling operations – by 23% from 1990 levels
We have reduced total greenhouse gas intensity per tonne of production:
- aluminium smelters – by 20% from 1990 levels
- alumina refineries – by 16% from 1990 levels
- aluminium rolling operations – by 20% from 1990 levels
Carbon Capture Technology
Alcoa’s global Technology Delivery Group, based at Kwinana in Western Australia, has developed ‘Carbon Capture’ technology that uses carbon dioxide (CO2) to treat bauxite residue. The process delivers significant greenhouse benefits by locking up CO2 that would otherwise be released to the atmosphere, as well as other environmental benefits in the management of bauxite residue.
Our first Carbon Capture plant is currently in operation at Alcoa’s Kwinana Refinery. The plant uses waste CO2 transported by a pipeline from a nearby ammonia plant and locks up around 70,000 tonnes of waste CO2 a year – equivalent to taking 17,500 cars off the road.
The Carbon Capture process has potential application for the global aluminium industry and we plan to install the technology at our refineries around the world, using waste CO2 from Alcoa refinery powerhouses.
Reducing perfluorocarbon (PFC) emissions is a key focus of Alcoa’s smelting operations’ climate change strategy. PFC emissions are produced by anode effects in the smelting process. Anode effects are caused by low alumina levels in smelting pots and are a major source of direct greenhouse gas emissions from aluminium smelters. Our smelting operations in Victoria have reduced PFC emissions by over 85% compared to 1990 levels. The Portland and Point Henry smelters are working to further reduce emissions through continuing improvements in process control and equipment.
Alcoa and Alinta have partnered to create cogeneration power units at Alcoa refineries. The plants produce both electricity and heat from the same fuel source, delivering greenhouse benefits. Gas-fired cogeneration is the most thermally efficient and greenhouse-friendly non-renewable energy source.
There are currently two cogeneration units operating at the Pinjarra Refinery. Cogeneration is around 75% energy efficient, compared with 30-50% for other power plants operating in WA. A year’s electricity from each cogeneration unit saves around 450,000 tonnes of greenhouse gas emissions each year compared to a similar sized coal fired plant – equivalent to taking 112,000 cars off the road. In addition, the cogeneration plants reduce Alcoa’s refinery emissions by 270,000 tonnes per year through more efficient steam generation – equivalent to taking a further 67,000 cars off the road.
Two Open Cycle gas turbine power plants commenced operation at Wagerup in October 2007 to supply reserve capacity to the market and may be converted to cogeneration units to meet future Wagerup steam requirements. Cogeneration plants at the Pinjarra and Wagerup refineries could save over 1.8 million tonnes of greenhouse gas emissions when compared to coal fired electricity generation. This is equivalent to taking 450,000 cars off the road in Australia.