Even with the increasing penetration of renewable energy in Australia’s power sector, fossil fuels still contribute 68% of Australia’s total electricity generation. Fossil fuels in the power sector predominantly consist of coal, natural gas (primarily methane) and oil (diesel and fuel oil). Coal alone makes up 47% of the total 272 TWh of electricity generation in Australia. However, to produce electricity using fossil fuel sources, large volumes of water are often required which can be a major issue in a dry country like Australia.
Coal
Forming the largest part of the power sector in Australia, coal mining and power generation from coal fired power stations requires a lot of water. Coal mining and coal fired power stations in Qld and NSW use 383 billion litres of water a year, with the power stations alone consuming about 160 ML per year. Coal mining is a water intensive mining operation and requires about 650 Litres of water for every tonne of coal produced. The water at coal mines, which is sourced from surface and groundwater, is used mainly used for coal processing, dust suppression and vehicle washdowns.
A typical 1000 MW coal fired power station, which requires about 9000 tonnes of coal a day, uses up to 2.5 GL of water per year. However, most of the water (around 75%) is used for cooling. Dry cooling, where cooling towers are replaced with air cooled heat exchangers, can be used to reduce the water use at coal power stations but results in lower electricity generation and higher carbon dioxide emissions per volume of coal. The reliance coal power plants have on a constantly available source of water means they are charged up to 12 times the wholesale price of electricity to ensure a consistent supply, making water efficiency essential.
Natural Gas
The second largest fossil fuel source in the Australian energy market (at 19% of total) is natural gas. Gas power plants in Australia are a combination of thermal gas (which use gas consumption to power steam turbines) and reciprocating gas (which can use unconventional gas sources like landfill or coalbed methane gas to drive a reciprocating engine). Water is consumed to produce natural gas through a process known as fracking whereby water is pumped into a tight rock formation to release the natural gas bound inside. Water use varies per well but is usually in the range of 10 to 20 ML of water to release the formation. Typically this water is taken from surface or groundwater sources although increasingly non-potable water is also being used.
Natural gas power plants are much more water efficient than coal power plants using approximately 20% of the water that coal power stations require as the cooling requirements for natural gas power plants are lower. Replacing existing coal plants with natural gas plants in the US between 2008 and 2014, has led to a reduction of the total withdrawal of water by the power sector.
Oil
The final fossil fuel source used in the Australian energy market is oil, usually in the form of fuel oil or diesel, which makes up only 2% of the total market. There are power stations using oil based turbines in Victoria, Western Australia, South Australia, Queensland and New South Wales. Water is used to refine crude oil into diesel and fuel oil. A typical refinery will use 1.5 times the water as the amount of oil refined but water use will largely depend on the refineries configuration. The overall water consumption of an oil-based turbine is similar to that of a natural gas turbine.
Moerk Water understand the complex water needs of the power sector. Contact Moerk Water today to find out how we can support you.
