Energy management

Coal seam methane, followed by electricity and diesel, are the dominant contributors to Rio Tinto Coal Australia's emission profile.

Addressing coal seam methane requires adoption of new technologies, which is included in the designing for the future section of our Climate Change Action Plan.

Rio Tinto Coal Australia's energy management objective is to improve energy use at our operations, projects and in the supply chain, and embed efficiency processes into our systems.

Our energy management programme is designed to address, understand, prioritise and reduce our energy use.  A major project is currently being implemented to meter electricity and fuel use of all equipment and facilities that consume at least 10 per cent of our energy.

In 2007, the Rio Tinto Coal Australia energy management programme reported avoided emissions of 15,500 tonnes of CO₂ equivalents. Programmes which contributed to this included:

• Coal & Allied sites saved almost 8,000 tonnes of CO₂ by using two per cent biodiesel.
• Installing more efficient engines in heavy mining equipment has allowed Rio Tinto Coal Australia to lower the amount of fuel consumed by its equipment and reduce carbon emissions as a result.  This work has had the added benefit of increasing the life and reliability of the equipment.  The engine repowers across the business saved over 4,000 tonnes of CO₂ in 2007.
• 370,000 litres of diesel and 980 tonnes of CO₂ was saved at Mount Thorley Warkworth through effective mine design focused at reducing haulage distances.
• Nearly 600 tonnes of CO₂ was saved when process pumps were changed out with high efficiency variable speed drives at the Hunter Valley Operations coal handling and processing plant.
• Installing timers and daylight sensors on lighting plants around Blair Athol Mine, Hunter Valley Operations and Mount Thorley Warkworth avoided producing more than 250 tonnes of CO₂.
• In 2007, Rio Tinto announced that its Brisbane offices would be moving to a new building in 2010.  The building will have a six-star Green Star Sustainability Rating and a five-star Australian Building Greenhouse Rating, reducing Rio Tinto's energy use, energy costs and greenhouse emissions.

Read our feature story on how we are replacing engines to reduce greenhouse gas emissions.

Results

Energy use

In 2007 we set voluntary targets for the amount of energy used to produce a tonne of product coal.  For Coal & Allied the target was 0.179 gigajoules (GJ) per tonne of product and Rio Tinto Coal Australia Queensland 0.109 GJ per tonne of product.

While a number of operations reduced their total energy use compared to 2006, energy use per tonne of product coal in 2007 was above target.  Coal & Allied operations used 0.249 GJ per tonne of product and Rio Tinto Coal Australia Queensland operations used 1.56 GJ per tonne of product. 

The amount of coal we produce is the major influence for the amount of energy we use and emissions we produce per tonne of product. Our 2007 results were largely due to lower than planned coal production because of severe weather events as well as port and rail constraints. Our operations are designed to efficiently remove large volumes of material and, therefore, decreased coal production does not generally result in decreased emissions per tonne of product, due to reduced economies of scale.

Greenhouse gas emissions

In 2007 we set voluntary targets for the amount of greenhouse gas emissions produced per tonne of product coal.  For Coal & Allied the target was 86.4kg of greenhouse gas equivalents (CO₂-eq) per tonne of product and for Rio Tinto Coal Australia Queensland 25.2kg of CO₂-eq per tonne of product. 

Compared to 2006, most of our operations reduced their total greenhouse gas emissions in 2007.  However, we did not achieve our targets.  Coal & Allied operations produced 89.8kg of CO₂ per tonne of product and Rio Tinto Coal Australia Queensland operations 28.2kg of CO₂ per tonne of product.   Like energy use, these results were due to lower coal production brought about by severe weather events as well as port and rail constraints.

Read Blair Athol Mine's results

Read Kestrel Mine's results

Read Hail Creek Mine's results