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Jun 13, 2023

Landfill gas could heat Hanmer Springs

Gas from a Nelson landfill could be used to heat Hanmer Springs-sized hot pools,

Gas from a Nelson landfill could be used to heat Hanmer Springs-sized hot pools, a council report says.

At the Nelson Tasman Regional Landfill Business Unit, general manager regional sewerage and landfill Nathan Clarke said the hot pools idea was one of two options that would be investigated to use landfill gas.

The unit manages regional landfills on behalf of Tasman District and Nelson City councils.

Clarke said the York Valley Landfill currently had about 70% of its gas that was not used for productive purposes, so there was a "significant amount of energy" that currently went to waste, sufficient "to run a facility similar to Hanmer".

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The business unit had engaged with an external consultant to look at the best two options for each landfill site, Clarke told councillors.

Of those, two options stood out, he said. One was a cogeneration facility, using the gas to make electricity, and using the waste heat for "productive purposes", such as a hot pools facility.

The other option that the consultants looked at was a renewable natural gas facility - "something that took the gas, cleaned it up and compressed it so that it could be transported to other locations".

This might be used to convert the crematorium from burning diesel to gas, for example.

Staff now wanted to move forward into a business case and look at coming up with one particular preferred option for each site, Clarke said.

"It's probable that we will do both preferred options in detail, to get the numbers around them, and from that then select the preferred option."

Councillors from both the Tasman District and Nelson City expressed enthusiasm about the prospect of hot pools.

Clarke said they had talked to the Nelson City Council parks and reserves team about locating the facility "in or around" the Brook Valley Holiday Park facility, which was "underutilized" and "next door" to the York Valley landfill.

Nelson City councillor Mel Courtney said he was excited about the option, and he imagined the community would be too.

"Yes, it's a fair expense, and it's a long way down the line before we could get to that having it operating, but I could see it would be a great synergy with the Brook Waimārama Sanctuary."

Tasman deputy mayor Stuart Bryant joined in on the reverie, picturing "native bush all round, native birds singing".

The unit manages two landfills: Eves Valley and York Valley, both of which have gas collected then burnt to lower greenhouse gas emissions.

Methane is around 25 times more powerful as a greenhouse gas than CO2, so it is flared to oxidise it and turn it into carbon dioxide.

Over 2021/2022, the business unit installed collection systems, gas wells and flares at the landfills. They also purchased the hospital's landfill gas boiler, which provides around 85% of the hospital's heat.

About 25% of the captured gas produced by the York Valley landfill is piped to a boiler at Nelson Hospital, the rest is flared. Gas produced by Eves Valley landfill is also flared.

A report presented to the Tasman District Council's Strategy and Policy Committee in April showed that of the council's net greenhouse gas emissions for 2021/2022, 59% came from landfill.

The report found that the council's ability to reduce its largest emission sources was "limited".

"It will be very challenging to meet our emissions targets unless significant progress is made towards reducing waste to landfill," the report said.