Powerco continues biomethane journey

North Island energy distributor Powerco has completed two feasibility investigations into upgrading biogas to biomethane for use in its gas network.

In April 2024 Powerco launched initiatives with Manawatū District Council (MDC) and Midwest Disposals to conduct technical analysis and engineering design at the Manawatū Wastewater Treatment Plant and the wider Manawatū Resource Recovery Park, and Bonny Glen landfill respectively.

Those assessments have now been completed and both conclude the projects are technically feasible.

Powerco is now proceeding into Front End Engineering Design (FEED) with MDC, and continues to evaluate options with Midwest Disposals.

The energy distributor is exploring producing biomethane as a low-emission, renewable alternative to natural gas.

Next steps in Manawatū

At the Manawatū site the feasibility assessment has concluded that producing biomethane is both technically and financially viable.

Powerco’s Head of Renewable Gas, David Hendry says the project is now moving to Front End Engineering Design.

“We’re now moving into Front End Engineering Design. That means we’ll start the design and detailed commercials of the plant that would upgrade the biogas produced on site to biomethane, as well the reticulation to connect it to our gas network.”

“That process will help us to refine our project costs, and support our final investment decision which we hope to make at the end of this financial year.”

MDC is continuing to design and build the Feilding Trade Waste Separation System, which will separate the treatment of industrial and domestic wastewater.

However David says securing feedstock at scale remains the key challenge.

“Getting enough organic feedstock from the Lower North Island via long term contracts into the Manawatū Resource Recovery Park to produce sustainable volumes of biogas is key to making this project viable. We encourage anyone interested in collaborating with us to get in touch.”

Evaluating options at Bonny Glen

At Bonny Glen producing biomethane is also technically feasible, but more evaluation is needed before a decision on next steps can be made.

David says there are two key challenges to the project.

“The Bonny Glen site is remote so the capital and logistical requirements to transport the biomethane need to be considered.”

“Also, future waste profiles and the variable nature of landfill gas generation – it varies depending on the composition and volume of the initial feedstock - means we would need to plan carefully if the project were to be viable long-term.”

A positive step

Overall, David says the feasibility assessments are a positive step for Powerco’s biomethane aspirations.

“Biomethane is already successfully flowing to gas customers in countries like Denmark – so the technology is available and proven. Aotearoa has the right feedstock to produce it here, too.” 

“Through these assessments we learned a lot about how we would produce biomethane, and we’re keen to keep going. There’s still a long way to go, but this was an important step on our journey.”