For years discount retailer PEP Africa has been struggling with unreliable, expensive, or no electricity supply in many of its stores across sub-Saharan African countries. The company spent an inordinate amount of money on diesel generators to keep the power on for many of these stores. A recent pilot project with Rubicon Energy, supported by Rubicon Analytics, proved so successful, that the company has rolled out solar and battery back-up power to 70% of its stores in Nigeria, Mozambique, Angola and Zambia.

The client’s requirements

PEP Africa needed a cost-effective solution to provide full power to stores that didn’t have access to grid power or diesel for generators, and back-up power for stores that used grid power. It wanted to limit its use of diesel generators as much as possible. The solution needed to be able to power, at a minimum, the stores’ main equipment including lights and plugs, alarm system, point of sale terminals and network infrastructure. It needed to be robust enough to withstand harsh conditions in remote rural areas. Because many of the stores are so inaccessible, PEP Africa needed to be able to monitor and manage the power remotely.

Furthermore, as PEP Africa has a fully-fledged installation team that is capable of implementing electrical, solar, and energy storage projects, Rubicon was asked to provide product training so that this in-house team could roll out the solution at scale.

The solution

After speaking to numerous suppliers, PEP Africa chose Rubicon in August 2019 to provide solar and battery power for a Cape Town pilot store made from six containers. For four months the store functioned on the solar power alone for up to eight hours per day without any problems. Because the pilot went so well, the containers and solar power equipment were disassembled and moved to the Zambian town, Kasumbalesa. There the store has been operating for nearly a year on solar power integrated with a lithium battery alone.

The success of the Zambian store secured the roll out of the same solar and battery equipment to 135 stores - more than half of PEP Africa’s existing brick and mortar stores in sub-Saharan Africa. PEP Africa’s priority was to use solar PV power for all stores that had roof access, and battery back-up for grid powered stores without place to install solar panels.

Rubicon Analytics’ divisional head for energy, Campbell Smith said: “What you basically have is a fully off-grid system in most cases, which is also fully automated, and is cost effective.”

Solar photovoltaic panels: Canadian Solar 360 Watt solar PV panels were used for this project. The solar modules and mounting structure used for the PEP Africa stores is easy to un-install, and in the case of containerised stores, can put into the containers and moved to a new location if needed.

Studer inverter technology: Rubicon used Studer Xtender inverters in the stores which used solar PV power. These inverters are comprised of a few components which act as the ‘brain’ of the system. The inverter has a controller unit which communicates with a Studer charger which is connected to the solar panels and battery. The system includes an automatic switch over function which allows it to automatically switch between solar, battery, generator and grid power as needed, without a store manager having to intervene.

When there is no sun and the batteries run flat, the system automatically switches the store to grid power, if available, or generator power – a relatively new technological capability. The ability to communicate with generators is a unique function, which other inverter manufacturers don’t offer. The conditions in which the generator will automatically turn on can be changed remotely and customised for each store.

Blue Nova lithium batteries: Rubicon went with Blue Nova’s 8kWh lithium battery packs which  are charged by solar chargers via the solar panels.

Tesla Powerwalls: The Tesla Powerwall 2 has been installed at some of PEP Africa’s Angolan stores and in one store in Lusaka, Zambia. The Powerwalls are fully-integrated, rechargeable AC battery systems. The 13.5kWh lithium-ion battery packs can be used with, or without solar power. The Powerwall has a large battery storage, and an in-built inverter and cooling system. It can be installed outdoors or inside, on the floor or mounted to a wall. It’s relatively small given the large amount of battery storage it has, which makes it perfect for stores which don’t have much space to store battery packs.

PEP Africa’s senior maintenance manager Jeanne Valentyn said the store manager in Lusaka hadn’t even noticed his store had been running off the Powerwall rather than grid power for more than 14 hours. “I asked him to check the data and that’s when he realised the municipal power had been off all day and they had been trading as though nothing had happened.” Smith said that this is a huge achievement.

Both the Studer and Tesla systems used in the PEP Africa stores are modular systems which can be upgraded at a later stage or integrated with different types of power later on. For example, solar PV can be added to a battery back-up system in the future.

Monitoring: The systems that have been installed at the PEP stores can all be monitored, configured, and programmed remotely through an online portal.

Client feedback

PEP Africa has 50 stores in Nigeria and will save R180,000 per year, per store on maintenance, fuel and generators once the roll-out is complete. In Angola, 90% of PEP Africa’s stores were running permanently on diesel generators. The company looks to save R250,000 per store, per year for its 63 Angolan stores.

Because so many of the stores run on diesel generators, PEP Africa will be able to pay off the new equipment within the first year of its use.

Valentyn was impressed with the solutions and support PEP Africa received from Rubicon. He had the following to say:

“We got support, guidance and inhouse training from Rubicon. Campbell travelled with me to Angola for additional support with a technician and we did training onsite. What stood out for us was having these guys available whenever you need them. They’re always there to assist. And if they can’t do it they’ll get someone else who knows the system to help.”

“If you crunch the numbers it’s a lot of money saved and it’s happy customers. The store managers are my customer and keeping them happy means keeping the lights and power on for them and boosting their sales.”

“For the last few months, it’s been better news than before because now the stores are able to trade 24/7.”

“We did a test run in Cape Town and the outcome we got was phenomenal.”

The future

Based on the results of the initial phase of the project PEP Africa decided to use Tesla Powerwall technology for all future grid-connected battery installations. They were impressed by the Powerwalls’ physical specifications, ease of installation and modularity.

PEP Africa, supported by Rubicon Energy and Rubicon Analytics, has already started rolling out 46 Tesla Powerwall 2 units in its Angolan stores. It takes only two hours to install a Powerwall compared to other battery systems which take up to two days to install and commission.

The rapid deployment of the Powerwalls will ensure that PEP Africa won’t experience any downtime in trading in Angola. In the future, these can be upgraded by adding integrated solar PV solutions to take the stores completely off grid.