A small residential development in Wanaka is going solar, in what may be a first for this district.

Solar panels and batteries will provide the primary source of energy for each of the 26 homes in The Terrace development and they will be linked together to essentially be operating their own mini power grid.

Each home will be fitted with an average of 20 photovoltaic panels and a battery with a 10kw/h storage capacity. But instead of each house having its own connection point to the grid, there will be just one connection point to the grid between all houses, allowing homeowners to share and trade energy between houses in The Terrace.

“Something like this hasn't been done in the Wanaka region before,” Wanaka Solar founder Dean Dunning said. “I think it’s going to be smart and will showcase this type of solar setup which should be able to be replicated elsewhere.”

Dean explained the detail of the concept: If we take a look at a single house, the solar on the roof will meet the daytime electricity needs, but any excess solar energy would go into the battery for use at night time or higher load periods. If the battery is full and there is still excess energy, then this will go out onto a mini grid, a commercially setup battery storage facility, which then distributes electricity to another house within The Terrace requiring energy.

With a regular stand alone solar equipped house, “excess energy would be exported to the grid for about 8c/unit; your next door neighbour could then buy this energy for 30c/unit. The Terrace model avoids this, as any excess power will go straight to your neighbour and your neighbour’s excess will come to you”.

“The model will be set up so it is financially beneficial to everyone living there,” Dean said. “The cost of power will be lower as excess power from your neighbour can be sold to you at a cheaper rate than you would buy from the grid.”

The Terrace project will also build resilience into the systems, so homeowners are protected from power cuts. “Every house will have its own battery; the systems we are using will automatically change over to back up power in the event of a grid failure,” Dean said. “The solar will continue to provide power and charge batteries which we think will be a valuable asset, as we live in an earthquake-prone region.”

Dean said he was working with an Auckland based company EMH Trade which has this model and platform working on some sites in the North Island.

He said the local climate is “absolutely amazing for solar energy 75 percent of the year” with only the winter months, particularly June and its regular inversion layers, providing only minimal sunshine hours. But this system will compensate for that by purchasing electricity at spot prices, taking advantage of cheaper rates, and storing the energy in batteries.

Dean said in general the demand for solar capabilities in residential homes in this district has expanded significantly in recent years. He said around 70 percent of his contracts were retrofitting established houses but, increasingly, more new builds were getting on board with solar.

The Terrace is being developed by David Reid alongside his major Alpine Estates residential development on land between Heritage Park and Aspiring Retirement Village. David said the plan was to have the first six homes in The Terrace under construction this year, and added the solar project was only one element of The Terrace’s sustainability intentions.

“As we are essentially controlling the building of about 26 houses … we have the ability to think outside the square with regards to sustainability,” David said. In addition to the solar mini-grid concept solar “we are looking at rainwater harvesting to ensure we have an additional water supply.”

PHOTO: Supplied