Electric trucks could boost South Island farming by powering the grid

As the South Island’s freight volumes are set to rise dramatically over the coming decades, innovative technologies are emerging that could transform how our farming and transport sectors operate — and earn money in the process.

One promising development is the potential for electric trucks to inject power back into the grid, providing a new revenue stream while supporting the region’s electricity system during peak demand.

The South Island boasts an extensive transport network: around 5,000 kilometres of state highways, over 35,000km of local roads, and more than 1,500km of rail lines, connecting farms, ports, and urban centres. Freight moves by road, rail, air, and sea — with major container ports at Lyttelton and Port Chalmers, and vital links to the North Island and international markets.

Freight volumes are projected to increase significantly, with an extra 47.7 million tonnes expected to be transported on our roads by 2042 compared with 2012. This means an additional 1.7 million truck trips per year. However, the South Island’s infrastructure faces challenges including natural hazards such as earthquakes, floods, and landslides that can disrupt freight routes and delay goods markets.

Currently, there is a heavy reliance on road freight, although shifting some freight to rail could improve resilience. In this evolving landscape, electric vehicles (EVs) offer more than just a cleaner way to move goods.

A recent report by Retyna and Concept Consulting highlights how electric trucks could become valuable energy assets for the South Island. The concept, known as Vehicle-to-Grid (V2G), allows EVs to send electricity stored in their batteries back to homes, buildings, or the wider grid when demand peaks—such as during cold winter evenings when energy use spikes.

For electric cars, this could generate an estimated $2,000 per vehicle annually for the electricity system.

For electric trucks, the potential is even greater. Trucks returning to depots in the early evening could supply power back to the grid, generating around $10,000 per truck each year. For example, electric milk collection trucks — which often operate less in mid-winter when milk production slows — could be fully integrated into the energy system. They would provide critical support during winter electricity demand peaks and recharge overnight when electricity is cheaper and cleaner.

This dual-purpose use of electric trucks aligns well with South Island farming realities. It can reduce operational costs for farmers and transport operators, increase energy security in rural areas, and help balance the grid during times of stress.

Additionally, it supports the broader push towards sustainable agriculture and low-carbon transport. With the South Island’s freight needs growing and the risks of transport disruption high, electric trucks equipped for V2G offer a compelling win-win: smarter freight solutions and stronger, more resilient power systems.