Cutting carbon, cutting energy: The journey at Backsberg
In 2006 Backsberg Estate Cellars became the first carbon-neutral winery in South Africa and only the third in the world.
Reflecting on the road he has travelled in achieving and maintaining carbon neutral status, estate owner Michael Back recalls that the magnitude of the task first became evident once the initial carbon footprint audit was completed.
“We engaged a chemical engineer from Johannesburg to do a carbon footprint audit. We looked at everything from our gate to the customer’s gate. We measured everything that left the estate and everything that arrived at the estate. We looked at emissions irrespective of where they came from in the operation. We also looked at where wine is going to in terms of transporting it, travel to promote it and so forth, everything,” explains Michael. “It was a daunting task, but we realised that we had to develop a baseline first, in order to really drive carbon emissions reduction. Moreover, energy should come from a renewable source, or be generated from waste. We went for the low-hanging fruit first.”
Low-hanging fruit included simple yet effective interventions, like replacing all light bulbs with energy-efficient fluorescent lights and installing polycarbonate skylights to let in natural light.
Installing clear polycarbonate panels and fluorescent lights has helped to reduce energy consumption at Backsberg Wine Estate.
Part of the audit looked at the amount of manufactured steel – which has a massive carbon footprint – used on the estate, and that drove the decision to buy smaller bakkies and tractors. Michael still drives the same Ford Bantam bakkie he bought back in 2006. “It’s done about 250 000km, and it’s still going strong,” he says.
Another early initiative was the lyre vineyard trellising system, which Michael first saw during a visit to Spain. The rows are planted 3.6 metres apart and alternate vines are trained in opposite directions, hence the term lyre. Although not suitable for all areas, this approach results in a greater canopy area per hectare. It results in a significant reduction in operating metres per hectare because there are fewer rows in the vineyard, which reduces the tractor operating time for performing mechanical functions in the vineyard. “It gives you more running metres of canopy per hectare, and less running metres of tractor road, which translates into lower fuel consumption,” says Michael. The savings are significant over the life of a vineyard.
The lyre trellising system, pioneered in Spain, results in more running metres of canopy per hectare, and less running metres of tractor road, which translates into lower fuel consumption.
With conventional 2.5m row spacing, assuming a speed of 4km per hour, using 4 litres per hour of diesel over 4 000 running metres per hectare, a tractor will use 4 litres of diesel per hectare.
In the lyre system, 3.6 metre row spacing gives 2 700 running metres per hectare, which means tractor time taken at the same speed and diesel consumption rate is 40 minutes, which will use 2.7 litres of diesel per hectare. Assuming 10 trips through each hectare per year, this equates to 13 litres less diesel per hectare per year, which over the 20-year life of a vineyard amounts to a reduction of 2 600 litres in diesel consumption per hectare. “Obviously we can’t just rip up established vineyards in order to implant the lyre system, but as we replant in the normal course of events, we will do so,” says Michael. Backsberg currently has 22ha under the lyre trellising system, and is replanting an additional 3ha this winter. Over time the majority of vines will be converted to the lyre system.
Temperature control during the red wine fermentation process is critical, and conventional systems, which circulate coolant around the fermentation vessels, are energy intensive. Michael calculated that cold water drawn at a suitable depth from the farm's dams could do the same job as a refrigerant-based cooling system, but using much less energy. But since then, Michael has implemented an even more energy efficient cooling system. “We’ve partially switched to using a biomass furnace, which runs on waste wood chips from a local sawmill, to generate chilled water through a heat exchange process,” he says. “It’s not a commonly applied technology, but it holds huge potential. Also, it is not reliant on sunlight for the creation of process heat.”
This biomass furnace, which runs on wood chips from a local sawmill, generates chilled water through a heat exchange process, which is used to control fermentation temperatures in the wine cellar, at Backsberg wine Estate.
A later and more significant change was the decision to raise all fermentation vessels in the cellar, which entailed building what amounts to a mezzanine level in the cellar. “By raising the fermentation vessels in the cellar, we can move wine largely using gravity. This translates into a reduction in electricity, since we’re not pumping grapes or wine. Not pumping translates into gentler treatment of the wine,” says Michael.
Raising the fermentation vessels in the cellar at Backsberg Wine Estate, allows wine to be moved largely by gravity, which translates into a reduction in electricity, and less pumping translates into gentler treatment of the wine.
Eleven years down the track and Michael is still on the same journey he started in 2006. He talks about his “playground,” an area set aside on the farm, where he is constantly experimenting and coming up with new initiatives to become even more energy efficient.
As a result, there is much more under way on the farm, and perhaps the most exciting initiative, as yet in its infancy, is Michael’s plan to make Backsberg entirely energy self-sufficient – with prickly pears.
This field of prickly pear bushes is part of a 10ha plantation that will provide feedstock for an anaerobic bio-digester, which will make Backsberg Wine Estate energy self-sufficient.
“We’re going to put in an anaerobic bio-gas digester,” explains Michael, “and the feedstock will be prickly pears. Not the fruit, but the fleshy leaves, which have a very high calorific value.”
The process generates mostly methane gas as anaerobic organisms digest the feedstock – in this case prickly pear leaves – in a closed system which excludes all oxygen.
“The methane gas can be burned to generate process heat, or it can drive a gas turbine to generate electricity,” says Michael. “The gas can also be liquefied and stored, or sold. Unlike sunlight, feedstock for a digester is available all the time, not only when the sun shines.”
On the question of how much Backsberg has reduced its energy consumption on its 11-year journey, Michael says: “It is almost impossible to reduce to a simple number the measure of the energy savings we have achieved, because our business has grown over the 11 years we have been on this journey. We are using more energy now than when we started, but if we had not implemented the changes that we have, we’d be using significantly more energy than we now are.”
“I’m an open-source kind of person. I’m happy to share what I’ve learned on my journey. Anybody who wants to come and visit the farm and see what we’re doing, is welcome to do so,” Michael concludes.
The Western Cape Government and City of Cape Town launched the Energy Security Game Changer in 2015 in order to ensure that the Province has a reliable, diverse and low carbon supply of energy. This is being achieved through creating an enabling environment for the uptake of rooftop solar PV, encouraging energy efficiency and the installation of efficient water heaters, and promoting a diversity of energy sources in the province, including wind, solar, and natural gas. The Province is challenging every person in the Western Cape to contribute to an energy-secure, greener future.