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Energy Audit – Case Studies

David De Vernon

David De Vernon

In mid-2013, David de Vernon, called me up and asked me to help him with some ceiling insulation, he lived in Somerset West somewhere up the mountain, where they regularly experienced sub-zero temperatures outside in winter while living in an uninsulated house. We helped them out with their ceiling insulation issue and he asked us for advice on renewable energy.

We chatted about renewable energy for many visits and many gallons of coffee later I had enough notes to write a book, so I wrote the book and published it on in 2015. David bought the book and read it well After he put the book down, David sold his house and lived in a small flat while he had a whole new house built. While designing the house with an architect he hired, he incorporated many of the principles written in the book and originally discussed at his home.

The house was built with floor insulation, wall insulation, double glazed windows, a heat pump to heat the hot water cylinder, an induction cooker, 3 air conditioners and all the appliances in the house were new A +++ super efficiency rated. as well as Led lights, thick ceiling insulation and tinting on the sun-facing windows.

Once the house was built we installed 16 x 330-watt solar panels on a 24 kW lithium battery on a 10 kW Victron inverter. The solar and battery runs everything from the oven to the geyser to the air-conditioners.

They opted for an electric heat pump heated hot water and an electric induction stove top to not be bothered by the need to manage gas bottles. They chose to heating the home in winter with air conditioners to not be bothered by the need to manage wood or gas.

Between  David and I, we have effectively created what I believe is the first fully energy-plus home in Somerset West, a house that produces more energy than it consumes over a year.

Since March 2018 they have spent nothing on electricity and have never had a power outage for any reason even though their neighbourhood transformer blew up and left the area without power for a week… twice.

What a time to be alive.

Talisman Tool Hire Strand, Laignsburg and Kleinmond

Talisman Tool Hire Strand, Laignsburg and Kleinmond

In February 2020, we were contacted by Mr. Koos de Villiers of Talisman Tool-Hire in Strand. He had recently built a new building for the Talisman Tool-Hire shop and had prepared the new building with basic infrastructure to go off-grid. This included a borehole, water tanks, a utility room for solar and batteries, a large north-facing roof and efficient systems all around.

We started by installing a 12 kW 3-phase solar PV grid-tie system, connected to the grid and registered to feed back excess power to the city for credit. The project was started in late May 2020 under trying and restrictive conditions of the COVID lockdown. The project was completed in July 2020 when the city them permission to connect and switch on.

From then even in July the system produced almost enough power to run all the operations and the business’s power requirements from the city dropped to near zero during the day. As the days got longer toward summer the system steadily produced more power until Talisman started to make a small profit from selling the excess power.

In 2021 load-shedding became a bigger problem and Mr. de Villiers commissioned Flagship Solar to install a battery and inverter system at his home to cover load-shedding. We were then also given the project to install a battery and inverter system at the talisman in strand. As the load-shedding problem became heavier over the months, we upgraded the system until we ended up with a 15 Kw Victron inverter with 12 kW of solar support and 28 kW of lithium battery.

In the building, there are now four businesses that run without any power outages or loss of production due to unstable or unreliable power. these are Talisman Tool Hire, Hi Services Gas, Campus Solutions and Drawa Wheelbarrows.

The boardroom has also become a favourite asset for Oom Koos to rent out to local entrepreneurs and a community of people and businesses have formed and thrived around the “Talisman Hub”

The client is so impressed with the system that we also did a fully off-grid solar and battery system each at Talisman Laignsburg and Talisman Kleinmond and two other private sites.

The combined flagship Solar systems at the work and private sites have brought joy to everyone involved as both in work and in home life the family is not burdened by power outages, load-shedding or tariff price hikes.

Vannie farm

Vannie farm

In February of 2021, we were contacted by a client on a small farm in Tesserlaarsdal. They lead a modest lifestyle, engaging in subsistence farming and cultivating garlic as a cash crop.

They have 8 small dogs, a beautiful art studio, a very small house near the middle of the land and a fairly large box-shaped warehouse store workshop toolshed all rolled into one near the back. They don’t use much electricity, probably only around 10–12 KWH or units of power per day, let’s say R500 of electricity per month. But it cost them no less than, R8000 in line fees from ESKOM per month to get it there, even though the transformer was paid off, so it wasn’t that.

We conducted a site visit to see what we could do for efficiency before installing solar panels, but they had already covered all those bases and just needed a good system to cover them for load shedding and for the weeks-long stretches of power outages every time the cables got stolen

The farm was connected via a 3-phase power cable, and 3-phase power was distributed everywhere on the farm where it needed to go, although nothing on the farm required 3-phase power to operate. So we specified a 5 kW single-phase Victron inverter with 14 kW of lithium battery and 12 x 460-watt solar panels, which we installed in and on the warehouse-workshop..

We also rewired all the distribution boards so that the farm could run on single-phase power only and powered up everything on the farm. We also supplied them with a 3 kW single-phase generator, which was programmed to load the battery while the farm still ran on the inverter. We also included a changeover kit to run the farm on the generator or a bigger rental generator if the need arose.

We commissioned the system in April 2021, and the client filed with Eskom to remove all the Eskom infrastructure from the farm.

A month later, we followed up with the client, and based on the monitoring that we had done on the system and the usage, we advised the client to switch from a gas stove and oven to an electric stove and oven because they always had too much power and could displace the use of gas.

They also switched from irrigating their farm once a week with the borehole to once a day since the borehole runs on the solar power and inverter system; it doesn’t cost anything to run. They also switched from mowing the lawn with a petrol mower to an electric mower.

Vannie Farm has been off-grid for water, electricity, petrol, and gas since May 2021. They have not paid a cent in electricity since we installed, and their power has never been off for any reason.

The system paid for itself in savings in just 28 months, and it still works like new.