Fonterra Tīrau – Load increase
When New Zealand’s largest dairy company, Fonterra, was expanding their Tīrau operation and wastewater plant, we worked closely with their team from inception to deliver the increased electrification needed to support the expansion.
Our team of highly-skilled network planning engineers worked with Fonterra’s chosen electrical engineering consultant to develop a comprehensive electricity architecture design to achieve the extra 1.85MVA capacity required – bringing Fonterra’s capacity requirement to 7.2MVA.
In our discussions and plans, we also factored in the likely further increase in electrification by Fonterra Tīrau’s operations in the near future – a further 1MW uplift, increasing the total capacity requirement to 8.2MVA.
For Fonterra to achieve increased electrification, we first needed to address the limitation in capacity from our Tīrau substation which supplies the factory and surrounding area. With the load increase at Fonterra, there was an immediate need to install a second power transformer, together with a new high-capacity feeder, two distribution transformers and associated 11kV switchgear.
The installation of a second transformer enabled sufficient capacity to cater for the growing load required at Fonterra. It also increased operational flexibilities to support our scheduled maintenance of the substation transformers, decreasing the need to interrupt customers’ power supply.
The work involved to increase the electrical supply capacity to the Fonterra site included:
• An 11kV circuit breaker added to the end of Powerco’s 11kV board at the dairy factory
• An 11kV bus coupler added to Powerco’s substation’s 11kV board
• A temporary power pole installed at the factory site and 11kV line from the pole to the on-site transformer
• The installation of an 11kV feeder cable from Tīrau substation to new switchgear and a supply distribution transformer at Fonterra
• Extending the Tīrau substation switchyard to allow for the installation of a second transformer together with the installation of 33kV and 11kV circuit breakers
• Fonterra’s onsite works included the installation of a dry-type transformer.
Operational considerations and challenges
Customers’ needs are different, and with this project it was important to be agile in the way we worked. This included adapting the project delivery schedule to meet Fonterra’s need for continuity of power supply during the peak dairy season. This saw the installation of a temporary power pole and 11kV cable connected to a transformer on-site to allow the network upgrade to continue while minimising any disruption to Fonterra’s business operations.
International shipping delays associated with COVID-19 caused challenges, with the need to ensure we had reasonable lead-in times for procurement of equipment, taking in logistics constraints. However, as with all projects of this size, we had robust contingency plans in place should the likes of shipping delays or other incidents led to challenges that had the potential to mean project deadlines were threatened. Despite logistics delays, the project was completed on time.
Capital investment for this bespoke project was contributed by Powerco and Fonterra.
Powerco’s investment was determined in step with its standard capital investment principles. The investment determination was run over five, 10 and 15 year-terms with a preference for 10 years given factors such as the potential variability in production affecting anticipated electricity distribution charges. Modelling of future distribution charges was based on Powerco’s asset based pricing methodology, applying forecast production loading.