As Sappi’s Divisional Nurseries Manager, Wynand De Swardt supervises the supply of more than 55 million plants each year, about 44 million of which are planted on Sappi plantations.
Under his leadership, these nurseries today are heated during the winter months with clean, green solar power. The project is just one of many accelerating our journey to decarbonisation at Sappi.
Q: Why, in a country like South Africa which has so much sun, does the nursery need to be heated?
A: Heating at the nursery is required for root initiation, faster rooting and improved hedge growth during winter months. During the scoping process of the rebuild of Ngodwana Nursery, we investigated alternative green solutions to generate heat and shift away from fossil fuels.
Q: What was the solution?
A: We eventually settled on solar thermal heating which is 100% green and is designed as a standalone ‘plug-in’ to the nursery heating reticulation network.
Q: Can you provide a brief explanation of how the solar system works?
A: The heat is collected during daylight hours by 216 solar evacuated tube systems and stored in an insulated 300 m3 water storage tank for reticulation to the nursery’s hot ring main pipe. The solar thermal collectors comprise solar evacuated tubes that collect solar radiation from the sun, combined with a manifold on a steel frame. Water temperatures of 70°C are achieved and stored for circulation through the three rooting and two mother plant (hedge) structures.
Q: How much energy does the system provide?
A: The system delivers an average of 4,000 kWh per day during winter months – a total of 488,000 kWh over winter months with a solar radiation average of 4.8 kWh/m2 per day.
Q: Could you sum up the benefits?
A: There are so many great ones! From reducing our operating costs to being carbon neutral with 100% green energy for year-round heating. The blueprint for this system can be rolled out to Sappi’s other commercial nurseries and, in fact, is already in place in our Forestry Research Centre.
It accelerates our journey to decarbonisation, and ability to reach our SDG #7 target to increase our share of renewable and clean energy.