A bio-energy expert believes Palmerston North City Council has a battle on its hands to make the beleaguered landfill methane gas project at Awapuni work.
After costing $1.6 million more than planned, and producing only half the gas for electricity generation that was hoped for, City Networks general manager Ray Swadel is asking for another $170,000 to salvage the scheme.
But this month, the council has heard about staff exceeding their delegated powers to approve extra spending above the original $2.6m price tag, and failure to capture more than half the methane expected. One staff member has resigned over the fiasco.
Bioenergy Association of New Zealand executive officer Brian Cox said he was not familiar with the Palmerston North example, but said each project was different and had different challenges.
He said a major challenge was perfecting the art of collecting gas from a landfill that was not designed for it. Some of the projects that were working effectively were landfills that were still being used, rather than closed sites like Awapuni, and they had been lined, piped and filled with gas extraction as part of the plan.
"They would have my sympathy, trying to do their best with a landfill that was not designed for this."
Mr Cox said it was still a challenge to turn great renewable energy ideas into projects that were economic.
"Wind has come of age, but only a few years ago was not considered economic."
He said there were several innovative options the city council could consider that would rescue value from what had already been invested.
One option was to link the gas from both the landfill and the sewage treatment plant so there was enough gas to provide adequate supplies to one of the generators.
That is a proposal Mr Swadel has put to the council. It would cost $100,000.
Mr Cox said storing gas from the sewage treatment plant rather than flaring it was another possibility, but that is not on the agenda.
Other projects used landfill gas to fuel vehicles rather than to generate electricity.
The process of extracting methane from landfills is not new in New Zealand. Mighty River Power was involved in setting up two of the first in Auckland in the early 1990s, but has since sold its interests as the capacity was too small for its business.
There are currently more than a dozen landfill biogas extraction projects operating.
The schemes work by collecting the gas created when compacted rubbish decays, and using the methane as fuel for electricity.
The co-generation plant was part of the Awapuni Sustainable Development Centre opened amid high hopes and celebration by former Prime Minister Helen Clark in 2007.
© 2011 Fairfax New Zealand Limited
