The power of sustainable design

Substations transform voltage from high to low (or the reverse), as well as performing other important functions. Traditionally, their construction has used materials that have negative environmental impacts, including reinforced concrete and polyvinyl chloride (PVC).

The Windsor Substation project in Hastings, was seen as an opportunity for Unison Networks to drive transformational change within the electrical distribution industry. Key to the success of this project was the collaboration between Unison Networks, Charissa Snijders Architect and Tricia Love Consultants.

The project was the first infrastructure building in the world to embrace the onerous sustainability principles of the Core Living Building Challenge, an international sustainable building certification. It was selected as the best option to help Unison Networks achieve its goal to create a blueprint for more sustainable substations to be built in Aotearoa New Zealand. The project team liked the fact that the Core Living Building Challenge was an entire philosophy of design. It also requires buildings to be tested over the following year to prove their construction and performance meets the design goals.

As part of the initial design phase, a Life Cycle Assessment was used to assess the direct and indirect carbon impacts associated with the construction and operation of the building, over its lifetime.

The building has strong environmental credentials:

• 209% reduction in embodied carbon for primary materials compared to a typical substation.
• Constructed using locally sourced materials as a priority, including 40 salvaged hardwood power poles from the 1950s. The team endeavoured to use products with zero Red List materials. Red List building materials contain chemicals designated as harmful.

Red List materials(external link) — International living future Institution

• 75% improvement in energy efficiency compared to the baseline substation. The design included the building being fully wrapped in insulation to help minimise fluctuations in temperature and allow us to shift from conventional air conditioning to a simpler mechanical ventilation system.
• Net positive with 3,315 kWh sent back to the grid.
• Additional resiliency through the use of dual 110V DC lithium ion battery energy storage.
• Captured rainwater and 30,000 litre storage tank supplies all water needs.
• 48.5% of materials sourced locally from within 2000km of site.
• 99% of construction waste by weight diverted from landfill.

During the 12-month performance period the building was monitored for energy consumption and energy production. The building produced 10,056 kWh and consumed 6,741 kWh. This provided a net Energy Use Intensity of 40.31 kW/m2.

In July 2022, the Windsor Substation was named winner of the Low Carbon Future Award at the New Zealand Energy Excellence Awards.

Project: Windsor Substation
Owner: Unison Networks Limited
Collaborators: Tricia Love Consultants, Unison Contracting Services Limited, LHT Design Ltd Consultants, Gemco Construction Ltd, South Pacific Landscapes, Hastings District Council, Xlam CLT panel providers
Architect: Charissa Snijders Architect
Main contractor: Unison Networks Limited
Date of completion: January 2022