In 2020, Celine Umurenzi was part of a project that aimed to connect some rural off grid areas of Bugesera District on solar mini-grid for them to get electricity.

At the foundation of the project, she had to collect the needed information for its development, spending most of her time navigating through the district.

In doing so, Umurenzi unearthed challenges that residents were facing, which included lack of a convenient means of cooking as well as a source of electricity.

"In those areas,” she explains. "Children were spending over three hours fetching firewood and by the time they would get home, it would already be dark yet they didn’t have electricity.”

Umurenzi brooded over a solution that could unravel the issue. She was aware that different improved cook-stoves were already in place, but their solution couldn’t handle the two challenges simultaneously.

"I wanted to develop a solution that could provide cooking energy and electricity,” she said, adding that her mind compelled her to carry out research and found out there was a way to produce electricity from the heat a cook stove generates.

She also learned about reports that show that Rwanda is among countries with a high rate of households who cook over an open fire jeopardizing their health, causing widespread deforestation, and burdening women and girls with hours of unpaid labor.

The biomass energy strategic plan by the Ministry of Infrastructure (MININFRA) 2019-2030 reported that 87 per cent of Rwandans use biomass as their primary energy for cooking whereas the fifth Integrated Household Living Survey (EICV5) reports that 49 per cent of all Rwandans still rely on unclean sources of lighting energy sources like firewood and lantern kerosene lamps.

This prevailing reliance on open fire cooking in rural Rwanda can be attributed to the slow adoption linked to the affordability of existing improved cook-stoves and their functioning features while the reliance on unclean sources of lighting energy is associated with the high costs of available clean energy sources.

With that in mind, Umurenzi went for a Master’s Degree in Renewable Energy and Energy Efficiency at École de Technologie Supérieure | Université du Québec, Montreal to look for advanced skills and knowledge to develop Candela Model 1: A Novel Electricity Generating Biomass Cookstove through Candela Tech Ltd, a startup she co-founded with Jean Claude Itangishaka.

"The stove generates heat and we use a thermoelectric generator to convert that heat into electricity,” she said.

Thermoelectric generator usually turns waste heat into usable power by taking advantage of a heat source and a cold sink. They are ideal for remote locations that are off grid but have a heat source.

In the development of Candela model 1, the generated electricity powers the fan facilitating the forced air draft stove independently of other sources of electricity, hence removing the barrier of disseminating the stoves in off-grid rural areas.

Umurenzi said the electricity generated by the stove exceeds 10 watts and enough to power the fan facilitating the complete combustion of biomass pellets and light led lamps substituting the use of kerosene lamps made in tin cans in rural areas.

She added: "The stove also has a functionality of generating electricity, giving users who ordinarily don’t have electricity access, the facility to charge their phones or plug in the LED lamp attachment.”

As for today, the stove’s raw materials are tree shavings, but according to Umurenzi, they want to use other types of organic waste to produce cooking energy.

"Several attempts to disseminate improved cook-stoves in rural areas have been made, but this one presents the bottleneck to being dependent on other sources of energy such as DC batteries that facilitate the complete combustion of biomass fuels,” she said.

Achievements and future plans

Umurenzi has developed a prototype of the stove, Candela Model 1, and five of its units are being used by five families in Bugesera District.

The innovator was among 15 others who secured $90,000 to scale up their projects through the phase 1 of Rwanda Innovation Challenges for Academia-Industry Research and Development Collaboration (RIC-R&D) Grant. The grant is spearheaded by the National Council of Science and Technology (NCST).

Umurenzi said she plans to equip Candela Model 1 with a 10W thermoelectric generator recycling heat inside the stove into electricity allowing the user to light their homes in off-grid areas.

Through Candela Tech ltd, she also seeks to develop the cook stove with complete combustion, reducing 90 per cent of indoor air pollution caused by unclean cooking and kerosene lamps.

That, she said, will reduce the time women and children, especially girls, spend preparing the meals of their families from 6 hours to 1 hour and enable them to participate in other income generating activities of their families.

She said they also want to increase revenues for the end-users (especially women) from spending more time on income generating activities and savings by using improved cook-stoves.

She disclosed that after designing the final version and having it on an international standard, they will kick off mass production and avail the products on the market.