Dannevirke solar farm project has change in direction

A floating solar farm is being considered for Dannevirke.

A solar farm which was initially proposed for under-utilised land is now being proposed for one of four wastewater ponds.

Peter Wimsett, Tararua District Council strategy and district development manager, spoke on the proposal at the October council meeting.

An evaluation had been done on several sites, and in a presentation earlier this year it was stated that one of the sites being looked at was under-utilised land near the Dannevirke Transfer Station.

However, at a following meeting, a local resident had brought up concerns over the land, saying it had been acquired by council through the Public Works Act.

A floating solar farm, on one of four wastewater ponds, was now being considered.

Rangitāne o Tamaki nui-ā-Rua chairwoman Mavis Mullins said the floatation came about because of the resident’s concerns.

“They didn’t want any further land used for any activity other than what it was taken for and we agreed with that.”

Mullins said the floatation was relatively new but it was proven.

Wimsett said the project was ambitious and it wasn’t often solar panels were put on top of water.

“The trick here is that they are trying to operate as a pond for wastewater and collect electricity from sunlight so they’re kind of competing because there’s biological activity that goes on in these ponds that need UV for the bugs to do their thing.”

He said they’d chosen that particular pond because it was the fourth pond at the end of the line of the processing and the intention when it was built was to be the overflow of stormwater inflow.

The panels would be see-through so the UV would still get through.

“It’s really the floating pods that are going to stop that sunlight getting through, so roughly 20% are the solar panels of that 40% area and 20% are the actual pods so we’re going to get decrease in the amount of light reaching into that particular pond and so our engineers are just assessing that so these are the detailed considerations that we’re just working through presently.”

The project had a major deadline of March 31, 2025 for the build to be completed and for at least 70 customers to be signed up to a new retailer that would benefit from surpluses made from the council paying for the electricity.

“This is why it’s seen as a procurement of electricity contract rather than a council build,” Wimsett said, noting that it wasn’t council taking the risks in building it.

He said Rangitāne, or the charitable trust, would be paid by council as an electricity supplier and any excess would be delivered to the power grid.

Mullins said the Ministry of Business, Innovation and Employment, which had provided a grant for Rangitāne to pilot a solar farm, was comfortable that they had moved in the right direction.

Councillors asked several questions around unintended consequences and risk management and it was explained in detail how those things would be anticipated and managed.

Council chief executive Bryan Nicholson reminded councillors that the purpose of the report was to provide an update in terms of the change of direction, but there was still quite a bit of work to do in the background.