Biogas - The Energy Wonder That's Under Our Noses
February 4th, 2020
What is biogas?
Biogas is produced from the anaerobic, oxygen-free digestion of organic matter. Various sources of organic waste can be used as feedstocks for the anerobic digestion process. These include industrial waste from food industries, agricultural waste, sludge from wastewater treatment plants and biowaste from households, communities and small-scale commercial and industrial activity.
Biogas is typically composed of 50-70% methane, 24-45% carbon dioxide and small quantities of other gases. It can be used directly onsite for local heat production using a boiler or it can be converted into heat and electricity using a combined heat and power unit. Electricity can be consumed onsite or exported to the grid, while heat can be used in local industrial processes.
Biogas can be turned into biomethane via an upgrading and purification process to separate methane from other gases, which can be used for cooking, heating and hot water. Biomethane can be further compressed or liquified to be used as vehicle fuel.
In addition to energy production, the anaerobic digestion process also produces the digestate, a nutrient-rich material that be used as a fertiliser and applied on agricultural land instead of chemical fertilisers.
Strong decarbonisation potential
Biogas is a renewable, dispatchable and local source of energy that can contribute to decarbonising multiple sectors across Australia’s economy. Under the Paris Agreement, Australia is working towards an emissions reduction target of 26-28% below 2005 levels by 2030. Biogas has the potential to contribute 12% to Australia’s abatement task.
The combustion of biogas is considered carbon neutral and can be used to replace fossil fuels for electricity and heat generation. Biomethane can be directly injected into our existing gas infrastructure, presenting an opportunity to decarbonise our gas consumption. This also allows energy to be stored in the gas network and despatched when required, particularly supporting intermittent solar and wind. Also, further compressing or liquifying biomethane can provide a clean fuel for transport. Behind electricity generation, the two largest contributors to Australia’s emissions are direct combustion of fossil fuels for industrial processes and transport.
Overall, there are opportunities to reduce emissions across the biogas value chain. The decomposition of organic waste releases methane, which is a greenhouse gas that is many times more potent in the atmosphere than carbon dioxide. Capturing methane emissions from landfill, animal waste and wastewater treatment plants for biogas production can also reduce Australia’s emissions.
Linking Power, Gas, Transport and Agriculture
Australia’s electricity generation sector is already decarbonising due to the boom in renewables facilitated by the Large-scale Renewable Energy Target (RET). Last year, Australia celebrated meeting the RET of 33,000GWh of renewable energy by 2020, which translates to 23.5% of Australia’s total electricity generation. However, more work is required to reduce emissions across the economy. While wind and solar will continue to be part of the carbon abatement story, renewable gases, such as biogas and hydrogen, present an opportunity to achieve deeper emissions reductions.
To date, the conversation about renewable gas in Australia has focused heavily on hydrogen. In November last year Australia’s energy ministers agreed to the National Hydrogen Strategy, which sets out the long-term vision for a competitive hydrogen industry in Australia by 2030. Critically, the combination of biogas and green hydrogen is a powerful solution to support the power sector’s decarbonisation efforts as well decarbonising the transport, gas and the agricultural sectors.
Benefits for Waste Management
In addition to carbon abatement, waste management is another pivotal challenge for Australia. The status quo of using and disposing items cannot continue sustainably. Across all levels of government there is a push to reduce the amount of waste being sent to landfill and a focus on circular economies. A circular economy maintains the value of products for as long as possible to reduce waste and improve environmental, social and economic outcomes.
By using locally produced waste as inputs and generating biogas and digestate as outputs, the overall biogas value chain is representative of the circular economy. Creating new value for waste can also support local economies and regional communities, creating jobs and offering new incomes sources, particularly for farmers. Typical income sources include revenue from waste treatment, savings from onsite consumption and sale of the digestate.
Despite these opportunities, Australia’s biogas industry is still emerging. Australia already has several types of feedstocks that can serve as an input to the anaerobic digestion process at its disposal. In 2017, there were only 242 biogas plants in Australia, half of which were landfills collecting landfill gas. A significant amount of this biogas is flared, rather than being used to its full potential as a renewable energy source.
In 2016-17, electricity generation from biogas was around 1,200GWh, representing only 0.5% of national electricity generation. Australia’s biogas potential is equivalent to almost 9% of Australia’s final energy consumption, or one-third of the country’s gas consumption. This is comparable to Germany’s production. Germany is a world leader, contributing 50% of European production – which is about 50% of global production. So, Australia’s potential is quite significant. Also, there are currently no biogas upgrading plants for biomethane production in Australia.
With only a small biogas industry, Australia is not taking advantage of the potential to reduce Australia’s emissions by an estimated 9 million tonnes per year. This could make a sizable 12% contribution to Australia’s cumulative abatement task of 395 to 462 million tonnes of emissions to achieve our Paris Agreement target.
Ways to Grow our Biogas Industry
So how do we grow a biogas industry in Australia? Biogas production has been driven by different objectives in different countries. In addition to reducing emissions, these include addressing landfill issues in the UK and Denmark, supporting renewable energy in California and Germany, improving residential access to energy in China, promoting alternative transport fuel in Sweden and supporting the agricultural sector in France.
Despite different and complementary objectives, countries with successful biogas industries have all employed some sort of policy support for industry growth. Common themes include renewable gas targets, feed-in tariffs for export of electricity generated by biogas or biomethane, additional investment support in the forms of grants and soft loans, support mechanisms targeting specific feedstocks and prohibition or restrictions on the disposal or underutilisation of organic waste.
Greater policy support for biogas is required in Australia to realise biogas’ potential. Most notably, the absence of a national target for biogas production is a barrier to industry growth. To ensure strong and sustainable development of a biogas sector in Australia, biogas projects need to be financially viable.
The introduction of the RET helped bring down costs of renewables projects by driving investment in solar and wind technology. The National Hydrogen Strategy stopped short of recommending a similar target for renewable gas.
Setting a renewable gas target(s) – even non-binding, aspirational targets – would help kick-start projects and build momentum for biogas in Australia and incentivise green hydrogen projects.
Report Spells out Opportunities for Biogas
In 2019, ENEA Consulting released the Biogas Opportunities for Australia report for Bioenergy Australia with support from ARENA, Energy Networks Australia, Clean Energy Finance Corporation and the International Energy Agency.
In addition to recommending a target(s), the report recommends a consultation to understand how existing policies could be adapted and new ones could be designed to support biogas, the introduction of waste management strategies to support feedstock quality and quantity for biogas production.
- Encourage plant operators, particularly landfill operators to maximise biogas use.
- Explore use of biomethane as an alternative vehicle fuel to assist with the decarbonisation of Australia’s transport sector.
- Improve regulatory clarity for digestive material as an agricultural fertiliser.
- Simplify approval processes for renewable gas projects.
Mendo Kundevski is principal of ENEA Consulting.
This article was cited from: http://tinyurl.com/ujvw3vs
