The scope of the report is to "outline how Australia’s gas supply and infrastructure can be a national advantage as our energy mix continues to evolve."
Summary report: Decarbonising Australia’s gas networks https://t.co/ExfzLTjH4T #ausenergy #gas pic.twitter.com/fSLT6VmcHj— Energy Networks (@EnergyNetworkAu) December 18, 2017
The reports author's missed the option being explored across Europe: make us of Australia’s gas supply and infrastructure as an energy storage system.
This new purpose for Australia’s gas supply and infrastructure has the potential to make a substantial contribution to the economy. For instance, a proposal for a multi-billion dollar development of pumped hydro energy storage "Snowy Hydro 2.0" is years away from becoming a reality. The gas supply infrastructure can begin providing this function almost immediately.
The report describes three technologies under the heading "Decarbonisation Pathways" -
- Biogas production – Biogas consists of methane and is already produced from municipal solid waste.
- Hydrogen: Hydrogen can be produced from natural gas or through electrolysis. Hydrogen creates opportunities for clean energy for households, businesses or transport and can also generate zero emissions electricity using fuel cells or gas turbines.
- Carbon capture and storage (CCS) refers to the process of producing decarbonised hydrogen from gas, coal, or biogas to remove carbon dioxide from the carbon cycle.
Biogas can be produced from a great many carbon-containing materials such as farm crop waste, municipal waste, sewage sludge, animal waste and timber waste. In each case about half the carbon combines with hydrogen from water in the mixture to form methane and the remaining carbon combines with the oxygen "left over" from the creation of methane to form carbon dioxide.The fourth technology that isn't mentioned in the Gas Vision 2050 report tackles both of the above issues:
The result is a gas that is about 50/50 methane and carbon dioxide. The carbon dioxide needs to be removed before the methane is suitable for injection into gas supply pipelines.
Hydrogen can be produced using surplus renewable energy to split water by electrolysis. This is a method of energy storage. Hydrogen may be injected directly into gas supply lines, but the proportion can be no more than 10 percent by volume.
Waste materials containing carbon can be reacted with hydrogen. In this process ALL the carbon is converted into methane and NO carbon dioxide is created. So there is nothing to separate from the biogas before it can be injected into natural gas pipelines. The 10 percent limit on the proportion of hydrogen that can be safely mixed with natural gas is no longer an issue...The biomethane produced via this pathway is achieving two purposes:
- It is replacing natural gas with carbon-neutral biogas.
- It is storing renewable energy in the form of methane for use as required.
This needn't be a permanent part of a zero-emission energy system. While battery capacity investment is ramping up, excess wind and solar power can be stored and distributed as hydrogen and/or methane in the existing natural gas system.
Burning natural gas in heating appliances will eventually be discontinued, but for now, a large number of these appliances are being used. It will be some time before they are all replaced.
Small distributed gas-fueled electricity generation can be up to 60% efficient. These do the job that batteries and pumped hydro will eventually do - when enough of them have been built.
Farmers can replace coal seam gas industry by manufacturing methane from crop waste that is combined with hydrogen made to store renewable energy.
When there are enough batteries and pumped hydro storage to eliminate the need for natural gas energy resources in Australia, this bio-methane can be used as feed stock in chemical industries to replace coal seam gas. It can also be exported as LNG, substituting for Australia's coal and coal seam gas energy exports.
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