Biogas: smells like a solution to our energy and waste problems | RenewEconomy

Biogas: smells like a solution to our energy and waste problems

Print Friendly, PDF & Email

Could what we flush down the toilet be used to power our homes?

share
Print Friendly, PDF & Email

The Conversation

rsz_image-20150113-23795-uzyxie
The Western Treatment Plant in Werribee, Victoria, largely powers itself using biogas – a by-product of sewage treatment. Jason Patrick Ross/Shutterstock

 

Could what we flush down the toilet be used to power our homes? Thanks to biogas technology, Australia’s relationship with organic waste – human and animal excreta, plant scraps and food-processing waste – is changing, turning waste into a commercial source of renewable energy.

A recent report suggests that Australia produces about 20 million tonnes of organic waste per year from domestic and industrial sources. This in turn accounts for a large portion of national greenhouse gas emissions. Manure from livestock industries alone accounts for 22 Mt of carbon dioxide equivalents.

Organic waste, when broken down by bacteria, produces a methane-rich “biogas” that can be used to generate electricity and heat.

According to one estimate, if all the organic waste from Australian domestic, industrial and agricultural industries was treated in biogas plants, it would have the potential to produce around 650 megawatts of electricity. That’s enough to power almost one million Australian homes.

How it works

Getting the process right can be tricky but the science is simple: fill an airtight tank known as an anaerobic (oxygen-free) digester with slurry made from biological waste, then let the bacteria get to work to produce a methane-rich gas that can be used to generate electricity and heat.

Nope, it’s not a giant golf ball. This container in Scotland is storing biogas, ready for energy production. Greener Leith, CC BY-NC

Use what you need to power your pumps, motors and circuitry, and sell the rest back to the grid so that in as little as five years you recoup what you’ve outlaid on your biogas plant.

Renewable energy provided 14.8% of Australian electricity generation during 2013. Bioenergy totalled 7% of this, with biogas contributing to about 2.0% of the share of total renewable electricity capacity. In comparison, wind stands at 26% while solar power is 11%. The bioenergy industry expects biogas could be more important than solar, and as important as wind. The remainder of Australian bioenergy comes mostly from the combustion of sugarcane waste, also known as bagasse.

The majority of biogas plants in Australia – upwards of 50 – are associated with municipal waste treatment facilities. Commercial operations include Melbourne Water and Sydney Water, which use sewage as their biogas feedstock.

Low-cost options emerge

The slow uptake of the technology, particularly in the intensive livestock industries, has been due to the difficult financial environment, policy uncertainty and grid connectivity.

Covered anaerobic lagoons, sometimes called ponds, are the preferred type of digester for Australian agricultural industries – they are a low-cost option which performs well under our warmer conditions with minimal maintenance.

The technology has attracted a lot of attention in the pork industry over the past 10 or so years with Berrybank near Ballarat and Blantyre Farms at Young using piggery waste as their major feedstock.

Abattoirs, dairies and poultry farms are also investing in biogas technology as they look for a means of solving their waste and odour problems as well as reducing their carbon footprints, not to mention their electricity and natural gas bills.

A biogas plant in Austria. rohkraft.net

 

 

The uptake of this technology has produced significant energy savings and environmental improvements for red-meat processing plants such as the JBS Dinmore facility and the AJ Bush Beaudesert rendering plant, both located in South-East Queensland.

The recent installation of covered anaerobic lagoons by Oakey Beef Exports and Darling Downs Fresh Eggs demonstrates the huge potential to adopt biogas technology in one of Australia’s key livestock-producing and food-processing regions.

ARENA puts Australia in global talks

Interest in using biological feedstock including manure has encouraged the Federal Government’s Australian Renewable Energy Agency (ARENA) to fund Australia’s involvement in the International Energy Association’s (IEA) Bioenergy Task 37: Energy from Biogas.

This funding, secured through the industry-funded body Bioenergy Australia, means Australia can sit at a table of global representatives to look at what is going right and what is going wrong in biogas production systems around the world.

Part of Bioenergy Australia’s involvement in Task 37 is to look at which Australian industries are hurting the most through waste disposal problems and huge power bills, and where it is feasible for biogas to turn that around.

If we get it right, biogas could be making a significant contribution to Australia’s Renewable Energy Target (RET) to deliver a 20% share for renewables in Australia’s electricity mix in 2020.

Bioenergy Australia’s aim is less concrete: that by 2020, bioenergy will be recognised and widely adopted as a sustainable resource in Australia.

The ConversationSource: The Conversation. Reproduced with permission.

Print Friendly, PDF & Email

4 Comments
  1. john 6 years ago

    Good luck with the message to regional councils full of real estate agents and no vision people who think development is a new road to some new suburb to be developed by the said councillor or associate.
    The usual solution is to burn off the methane without turning it into power, and claim credits for emitting co2 not methane.

    • Harry Verberne 6 years ago

      But the best solution that is not the denialist solution is to do what the article suggests. And there is plenty of scope for that.

  2. Vic 6 years ago

    Apparently a lot of the damage being done to the Great Barrier Reef is caused by fertiliser run-off from farms situated adjacent to the coast.
    It seems to me we could extract a lot of this nitrogen out of the rivers by maintaining aquatic plant farms near the river mouths, using floating plants like water hyacinth, duckweed, azolla and salvinia. These plants could easily be harvested on a continual basis and fed to anaerobic digesters to produce carbon neutral biogas, with a by-product of liquid fertiliser that could be sold back to the farmers that cause the nutrient problems in the first place. This is an example of what a sustainable industry might look like.

    Perhaps a digester could be located on Curtis Island with its product used as a supplementary feed source for the LNG plant. Alternatively, the aquatic plant farms and digesters could be thought of as a “front end” for gas fired “peaking plants” delivering clean electricity at times of highest demand.

    Interestingly, Queensland ALP is now promising to spend $100 million (should they be elected) to try and address the issue of fertiliser run-off.

    “Labor said it would also reduce nitrogen run-off by up to 80 per cent in key catchments by 2025 and form a high-level taskforce to determine the best approach to meeting targets.”

    Fortune favours the brave ?

  3. Jan Veselý 6 years ago

    Biodigesters are proven technology. Germans have about 5 GW of them, in Denmark has one almost every farmer.
    But it is not cheap when you just produce electricity. You have to have use for the heat and the digestate.
    And also you to set incentives to use organic waste, no specially planted crops.

Comments are closed.

Get up to 3 quotes from pre-vetted solar (and battery) installers.