A project of the Antenna Foundation
Constant power cuts were a problem for the Gacha Foundation in western Cameroon. With the new DConnect® solution from innovenergy® and the Antenna Foundation, there is finally continuous electricity – and it is fully ecological! In Africa, of all places, an emerging continent full of opportunities, this state-of-the-art technology is being implemented for the first time as a pilot project.
Cameroon has a very low electrification rate of less than 23 %. The people who are connected to the electricity grid struggle with regular power cuts. Many small businesses and NGOs therefore rely on emergency generators for their daily work. This is not only ecologically questionable, but also leads to high costs for those concerned with constantly poor availability of electrical energy. Due to these problems, more and more companies in Africa are opting for off-grid photovoltaic systems. Although the prices for solar systems have dropped massively in recent years, the storage of the electricity generated is still a weak point. Lead-acid and lithium batteries are widely used, but they pollute people and the environment both in production and disposal. Current inflation and difficult procurement conditions due to disrupted supply chains also make lithium batteries difficult to buy.
The Swiss salt battery storage systems from innovenergy® are increasingly proving to be a real alternative. On the one hand, they are environmentally friendly, and on the other hand, they have a very long life expectancy of 15 years or more. The special thing about these eco-batteries is their robustness even under extreme environmental conditions such as heat. That is why salt batteries are very predestined for use in Africa.
Foundation Gacha is located on a hill in Bangangté and there are two different circuits. On one side of the hill there are many administrative buildings as well as a library, a museum, some workshops and a children's house. On the other side of the hill are other buildings such as a hotel, a restaurant and vocational training facilities for metalworking and a carpentry workshop. The two electricity circuits run separately and were each powered by their own diesel generator when the main electricity failed. These power problems greatly affected the Foundation's operations.
Already at the beginning of 2019, a larger solar system was to be installed at Foundation Gacha, but there was no suitable storage technology for hot Africa. Lithium batteries were out of the question due to their lack of safety, especially in high outdoor temperatures, and their lack of robustness. Lead-acid batteries were also not a solution due to their short lifespan and toxic waste. Salt batteries are the ideal solution, which is why this project came to fruition in 2020.
The technical design was created by the staff of the Antenna Foundation and the company innovenergy AG. They were supported by technicians from the local partner «African Solar Generation» (ASG) in Cameroon.
In the first half of 2021, the photovoltaic system with 61 kWp was installed by the staff of the Fondation Gacha as well as the local solar company ASG. The two salt battery storage tanks, consisting of two blocks with once ten and once four salt batteries, were installed in November and December 2021 by the technicians of Antenna and ASG. The photovoltaic field is located about one kilometre from the battery sites and supplies the two battery storage units via a corresponding DC link. The entire system went into operation at the end of December 2021 and has been working flawlessly ever since.
A DC link was installed as a connection between the solar system and the two battery stations. The decision for a DC link is mainly based on the fact that inverter losses should be avoided.
A solar charge controller (MPPT) is installed at the output of the photovoltaic system, which keeps the output voltage constant at 850 VDC and thus supplies the DC link with energy. The distance to the first battery block is 250 metres. Here there is a 10 kW Trump DC/DC converter that converts the 850 volts from the DC link to 48 volts battery voltage, as well as three 15 kVA Victron inverters to supply power to the building loads.
After that, the DC link extends another 750 metres to the second battery block and second building complex. Here there are three DC/DC converters and the same configuration of inverters. The two groups of buildings are not connected to each other on the AC side. The total storage capacity of salt batteries is 134.4 kilowatt hours.
The surplus solar energy is not fed into the public grid because the Cameroonian electricity grid is far too unstable and it is very difficult to obtain a feed-in permit.
The following objectives were set for the project:
- Successful planning, installation and operation of the solar system with salt batteries as storage and functioning DC link at Foundation Gacha in Bangoulap, Cameroon.
- Training of the local solar company African Solar Generation (ASG)
- Start of multiplication of the project
All goals were achieved!
Successful planning, installation and operation of the solar system with salt batteries as storage and functioning DC link at the Foundation Gacha in Bangoulap, Cameroon
At the Fondation Gacha, a 61 kWp photovoltaic system has been built in combination with 14 salt batteries. The diesel generator and the public grid remain connected to the new system. However, the aim is to use them as little as possible. The goal is to be able to operate the entire plant as self-sufficiently as possible in the future.
Training of the local solar company African Solar Generation (ASG)
During construction, four students from the CMPM (Université de Montagne) helped with the construction of the DConnect® system and were able to gain practical experience. In parallel, training was provided by Fima innovenergy AG in Switzerland. Originally, it was planned that Cameroonian technicians from the ASG company would travel to Switzerland for training. Due to travel and visa restrictions during the Covid 19 pandemic, only the two European employees were able to undergo training in Meiringen. These two then passed on their knowledge to the eight Cameroonian technicians and engineers.
Start multiplying the project
The demand for environmentally friendly and above all robust batteries is very strong. The local partner ASG has already started to install batteries for smaller photovoltaic systems. These are two banks, a private French company, a farm and a hospital in Cameroon.
Other salt battery storage systems have been installed in Ghana. The Antenna Foundation and ASG are in contact with NGOs and local solar companies in various African countries that are very interested in salt battery storage systems and DConnect®. Together with an investor, 26 salt batteries were pre-ordered and delivered and installed in November 2022.
The project in the Foundation Gacha in Cameroon is a complete success. Not only were specialists trained on site, but further projects were implemented and interested parties were won. The hunger for energy in Africa is greater than ever. The increase in fuel prices has not only shaken the Western world, but even more so the developing countries. Those without oil reserves are particularly hard hit. Photovoltaics remains THE renewable energy with the greatest potential for such countries. However, clever storage solutions are needed: Lead-acid batteries have had their day and lithium batteries are becoming more and more expensive and are now difficult to obtain due to the growing e-mobility. Salt batteries for stationary systems, on the other hand, are becoming increasingly popular due to their robustness and environmental sustainability. The salt battery storage systems and the intelligent DConnect® system from innovenergy® are not only predestined for Africa, but also for Europe's grid requirements.