Tapping biogas latest cost-saving solution

While there is nothing new about biogas – the product of the age-old anaerobic digestion process – the case for collecting the methane-rich gas to generate heat or energy is picking up pace as an avenue for energy cost savings.

CST Wastewater Solutions Managing Director Michael Bambridge said rising electricity and waste disposal costs are slowly but surely improving the business case for biogas projects in Australia, with the results of a recent executive survey showing record openness to sustainable alternatives. 

CST recently interviewed more than 60 senior executives in production, engineering and sustainability industries and found over 90% disagreed with the statement that sustainability is “never likely to be profitable”.

“Most groups we spoke with agreed the time is right for wastewater-to-energy projects,  with the technology well developed in other countries,” Bambridge  said.

“There is now growing enthusiasm that waste-to-energy projects could be developed with financial realism, rather than purely government handouts.”

In Australia, bioenergy makes up just 0.9% of all electricity generation, and biogas accounts for just a quarter of that figure – 0.2%. 

There are an estimated 155 anaerobic digestion facilities, including landfill, now generating biogas across the country, which fed predominantly by sewage sludge and landfill, followed by industrial waste and agricultural waste.

A recent Australian Academy of Technological Sciences and Engineering report found biogas generation and electricity co-generation from sewage and waste becomes financially viable once a treatment plant reaches typical mid-range size (50ML/d).

However, biogas production beyond on-site needs remains for the most part financially unattractive, with feed-in tariffs at around four to eight cents a kWh.

“Access to the grid can be bureaucratic and costly, as well as time-consuming,” Bambridge said. 

“It makes more sense to use the biogas for your own benefit than try and put it into the grid where you are getting a poor return.” 

Bambridge said one way to ensure biogas project viability could be to adopt the Asian model of community digesters.

“Digesters shared by a number of industries may need to be adopted, particularly in high value food regions,” he said. 

“With the multiple and consistent wastewater streams from these food regions, local community digesters would allow Australia to start to achieve its wastewater-to-energy potential.”

To read about biogas in more detail, see the in-depth feature in the latest issue of Current magazine.