Natural gas is an incredibly versatile fuel - as well as being used as an efficient energy source in its own right, for heating, cooking and hot water, it is also a means for electricity production. Gas power stations convert the heat energy from the combustion of natural gas into electricity, which can be used in homes and businesses. With greater operational flexibility and being cleaner burning than coal power plants, more and more gas-fired power stations are being built across the globe and, today, natural gas produces around 15% of Australia’s electricity.
Open cycle or combined cycle?
There are two main types of power stations used to convert natural gas into electricity - open cycle and combined cycle. The most common of the two is open cycle, in which natural gas is burned to produce pressurised gas. This powers a turbine, which is connected to a generator, causing the generator’s magnets to spin and create an electrical current.
In a combined cycle power station, the waste heat from the gas burnt to operate the turbine is used to boil water and create steam, driving a second turbine to produce even more electricity. This allows such power stations to convert as much as 50% of the energy contained in natural gas - far more than the 33% conversion of coal power stations. For this reason, combined cycle gas-fired power stations tend to be used to supply daily baseload power, whilst open cycle stations operate during peak demand.
Benefits of gas-fired power stations
One of the major advantages of using gas to generate electricity is that gas-fired power stations have extremely quick start-up times, which is why they’re often used to meet peak power demands. It takes a mere 10-20 minutes for a gas turbine power station to reach full load capacity, compared to multiple hours for coal power stations and up to two days for nuclear stations.
As a clean burning fuel, gas also produces around half the carbon emissions of coal. Gas starts out with a lower carbon content than coal and the greater efficiency of gas-fired power stations means that it produces up to 60% less carbon. Couple that with the fact that gas doesn’t release some of the toxic substances that coal does upon combustion and using gas to generate electricity is far better for the environment than using coal.