Food waste to energy: Auckland scraps converted to gas and fertiliser, but uptake lags

More than half of Aucklanders are not actively using their food waste collection bin, two years since the collections first started.

The programme has converted 62,000 tonnes of organic material to fertiliser and renewable energy for the national grid, but only about 40% of households and businesses that received a bin are actively using it.

Parul Sood, Auckland Council deputy director – resilience and infrastructure, said there is a lot of variability across different parts of the city, but overall, Auckland could do a lot better.

Sood said there is enormous potential for the programme to produce a resilient form of energy, especially at a time when global supply chains are under stress.

She said every peel, coffee ground or mouldy piece of bread that is put into the food scraps bin results in less waste going into landfill and contributes to producing renewable energy.

Sood said, as the food waste is produced locally, we are less reliant on supply coming from overseas, so this is a win-win situation.

She encouraged any Aucklanders who have been slower on the uptake to start using their bins, calling it a “simple change” people can easily make in their own homes.

Auckland Council deputy director – resilience and infrastructure, Parul Sood. Photo / Auckland Council

Ongoing conflict in the Middle East continues to disrupt shipping vessels transiting the Strait of Hormuz, placing a squeeze on oil and other goods, including the raw materials used to produce fertiliser.

Damage to processing facilities across the Gulf States is also destabilising fertiliser production as volatile fuel prices remain a leading topic of conversation for policymakers, businesses and industry groups.

Ecogas general manager Andrew Bedford said energy security is a very real issue in New Zealand at the moment.

The company owns the anaerobic digestion plant at Reporoa near Taupō, which breaks down organic material and turns it into bio-methane and the regenerative fertiliser Fertify, which is applied to farmland around the district.

Bedford said food scraps from Auckland kerbsides could make up between 30% and 37% of the total volume per month.

He said the gas produced at the site is a significant amount when considered alongside household residential use.

Bedford said, depending on demand, the volume on the line can provide all the gas requirements for Taupō and Reporoa.

Last August, Environment Canterbury granted Ecogas resource consent to build another organics processing facility in Christchurch.

The plant has capacity to receive 100,000 tonnes of organic waste every year. It is expected to start commissioning early next year and be fully operational by August.

Bedford said it will convert organic food and green waste into biomass fuel briquettes.

These can be purchased as a drop-in replacement for boiler owners around the Canterbury region who might be using coal or wood chips.

Bedford said these forms of bioenergy are helpful for hard-to-transition industries but said the Government also needs to get involved.

He said he wanted more regulations, in order to move organics away from landfill, and better certainty about protecting energy security for the future.

Bedford said New Zealand cannot delay action and keep relying on short-term solutions.

Energy Minister Simeon Brown. Photo / Mark Mitchell

Energy Minister Simeon Brown said New Zealand has a real opportunity to produce more of its own fuel, including bioenergy.

He said the Government is focused on cutting unnecessary red tape to unlock private investment across a range of fuel sources to deliver a more secure and affordable energy system for all New Zealanders.

Claudia O’Neill is an Auckland-based Multimedia Journalist for Newstalk ZB with an interest in science, health and geopolitics. She holds a Bachelor of Science degree from the University of Auckland and a Postgraduate Diploma in Journalism (Distinction) from Massey University. She joined NZME in 2023.