In recent years, there has been a growing interest in sustainable and energy-efficient solutions to reduce the carbon footprint of the transportation industry, Eamonn Ryan writes. This is Part 2 of a three-part series.

As with any technology, solar-powered refrigeration systems have limitations. Battery sizing, rate constraints, and limited roof space for solar panels in smaller trucks are identified challenges. To address these, NextDrive customises designs to minimise damage risks and optimise efficiency. Hurter acknowledges ongoing technological advancements, emphasising the evolution of battery capacity and solar panel efficiency over the past six years.
Hurter believes that in time all technological challenges will be overcome. “As manufacturers of batteries, we’ve witnessed remarkable progress, especially in battery capacity. Over the past six years, there’s been a 40-45% increase in capacity, with batteries becoming physically smaller. Similarly, solar panels have evolved. We started with 250W (and we now use 420W, as this is what fits well on the trucks) though you get up to 600W now. The technology is advancing in the right direction, making it increasingly viable. For smaller units, it’s already making sense, and we’re conducting testing on larger trucks to determine feasibility. Given that it’s a hybrid system, always with diesel as a backup, it’s about fine-tuning and conducting proof of concepts to ensure practicality and efficiency.”
NextDrive collaborates with major roleplayers in refrigerated transport – Transfrig, as well as retailers such as ShopRite – which through Transfrig have integrated solar systems into approximately 90% of its fleet. Each is tailored to unique needs, and it recently assisted Checkers to roll out its first fully-electric truck. “Solar systems power critical components, showcasing substantial savings, including an annual saving of close to R60-million in diesel costs alone for ShopRite’s fleet,” explains Hurter.
He notes that on average, customers save 4.8ℓ of diesel each day per trailer, with the return on investment for a typical solar logistics investment being 1.4 years from date of installation, based only on diesel savings.
Given the extent of potential savings, he believes all refrigerated transport will ultimately go solar-powered unless physically unfeasible. “The challenges come into play with larger trucks, around 14m in length, where the battery system’s cost becomes economically challenging. Capital expenditure on solar systems must align with a sensible return on investment, factoring in financing. Another challenge is the physical weight of batteries; with larger trucks, it’s essential to consider weight limits on our roads. The concern is that adding significant weight may require reducing the truck’s cargo capacity.”
This is an industry still at the commencement of a growth phase. Regarding competition, Hurter acknowledges emerging players in South Africa-based solar logistics, but considers the current landscape a ‘blue ocean’, and one in which they have a long head-start. However, he anticipates increased interest and competition due to growing tax incentives, making their approach more compelling.
The solar incentive is contained in section 12B of the Income Tax Act, being a 125% deductible on business income tax by investing in solar.
This all means that at the moment, the bulk of NextDrive’s work consists of retrofitting. Consequently, the company specialises in augmenting various refrigeration systems, retrofitting solutions to serve as backups and eventually becoming the primary power source. However, ShopRite has also adopted a standard practice of equipping every new vehicle with its solar system, says Hurter. He adds that successful proof-of-concept trials with Food Lovers Market and in collaboration with Transfrig, have showcased the effectiveness of solar panels in powering three-phase (diesel-electric-solar) systems off the grid for a week without diesel usage.
Traditional diesel refrigeration systems are primarily being replaced by silent nitrogen refrigeration systems. Hurter adds that these units have an operating life of up to 12 years with significantly reduced maintenance and operating costs.