Business context
Sector: Devan Plastics - manufacturing. Acquasol - commercial renewable energy and solar development, specialising in floating solar.
Location: Tauriko, Bay of Plenty, with a second manufacturing site in Christchurch.
Scale: Devan Plastics employs about 60 people. Acquasol operates with a small core team and uses specialist contractors and partners for engineering and installation.
Devan Plastics is owned by Jim Barlow, while Acquasol is jointly owned by Jim Barlow and CEO Locky Mulholland
The challenge
Devan Plastics makes water tanks, sewage systems and stormwater holding tanks at its Tauriko site. Its manufacturing operation is energy intensive, using large rotational-moulding equipment and ovens, with significant electricity and gas consumption. Rising retail electricity prices and the end of its contract with its previous electricity retailer pushed the business to consider solar to manage energy costs.
The original plan was to fit around 410 panels, at 460 watts each, representing approximately 189 kWp of solar capacity across the factory roof. Engineering checks found the existing roof could only accommodate about 140 panels, or approximately 64 kWp, well short of what the business needed. Like many existing industrial buildings, the roof had not been designed to carry the extra permanent load of a large solar array.
The solution
Devan Plastics went to market for its next electricity contract and put solar into the tender, approaching six retailers. Ecotricity won the business, offering a competitive import rate along with the best export rate on offer, at 12 cents per kilowatt hour. Devan Plastics' sister company, Acquasol, develops commercial solar projects, with a focus on floating solar, alongside rooftop and ground-mounted solutions. It installed 140 solar panels on the roof of the factory the two businesses share.
To address the remaining requirement, Acquasol is developing options to supply Devan with renewable electricity generated from an off-site solar project. Under the proposed arrangement, that renewable generation would be matched commercially against Devan's electricity consumption through its electricity retailer. This is commonly referred to as "sleeving". Ecotricity would facilitate the retail and settlement arrangements between the generator and Devan. The objective is to provide greater long-term price certainty and secure a component of Devan's electricity supply from renewable generation at an agreed price.
CEO Locky Mulholland notes that much of New Zealand's electricity network was historically designed around electricity flowing from large centralised generators through transmission and distribution networks to consumers. The rapid growth of distributed generation, including solar, means networks increasingly need to accommodate two-way power flows. Connection capacity and approval processes can therefore be a significant constraint for new renewable generation projects. Working through that constraint is a wider system challenge, not just one for Devan Plastics and Acquasol.
Results so far
The rooftop solar system now meets a meaningful share of Devan Plastics' electricity use, even with the shortfall still to be made up. The business consumes about 80 per cent of the energy generated by its rooftop solar system. The system does not include battery storage. Any surplus power, usually generated at weekends when the factory is closed, is exported to the grid. The system supplies about 22 per cent of the business’s total electricity needs. Locky estimates cost savings of about $20,000 in the first year against an investment of $120,000.
Devan Plastics is also investigating additional solar generation for its Christchurch manufacturing operation.
Locky's advice to other businesses considering solar is to establish the building's structural capacity and electricity load profile at the beginning of the process rather than assuming the roof can accommodate the required array. For new industrial buildings, he believes solar, future battery storage and other renewable-energy requirements should be considered during the original structural and electrical design rather than retrofitted later.