Iterate, Refine, Test: Biochar Bricks

Converting invasive plants into a nature-positive local fuel source

Over the last year, the SEPALI Madagascar agroforestry and biochar team has used a CPALI seed grant to iterate fuel "bricks" made from invasive water hyacinth combined with local seeds and cemented with banana glue. These team-developed biochar bricks are now powering specially-designed cookers to reduce charcoal and firewood consumption for dye baths at our artisans workshop in northeastern Madagascar. Next steps: working with local farmers to produce a year's supply of biochar bricks for our social enterprise. And testing the cookers that run on them in home environments to evaluate potential to scale to new users.

SEPALI Madagascar Director Mamy Ratsimbazafy comes together with team members to train local farmers in water hyacinth biochar production in October 2025. (Photo: SEPALI Madagascar)

Problem plants

Invasive water hyacinth (Pontederia crassipes) is a big problem this season in northeastern Madagascar. The non-native plant clogs rice paddies and chokes local waterways. Converting it to fuel takes effort and know-how, but it could be an important win-win for people and nature.

Invasive water hyacinth collected by the SEPALI Madagascar team for biochar brick production. (Photo: Matthew Scott)

From idea to action

Over the past year, the SEPALI Madagascar agroforestry and biochar team has worked to hone a biochar brick design that replaces forest-depleting charcoal and firewood with invasive plants and locally available inputs. One person can produce an estimated 20 biochar bricks per day.

Tsoly from the SEPALI Madagascar team transports handmade invasive biochar "bricks" to dry them in the sun before they are used to fuel cookers to dye silk and raffia textiles. (Photo: Rachel Kramer/CPALI)

Design, refine

The team's new bricks are made from water hyacinth combined with local seeds and sealed with banana glue. They're designed to fit inside the specially crafted stoves in our artisans' workshop. An estimated 1,500 biochar bricks will be needed per year to power the workshop's dye baths, which consume approximately 4 biochar bricks per day.

A water hyacinth biochar-fueled cooker boils a dye bath containing local lichens that give natural silk a yellow color. (Photo: Rachel Kramer/CPALI)

Train

SEPALI Madagascar Director Mamy Ratsimbazafy and the biochar team are now training community leaders in brick production to scale the availability of this new fuel source. Scaling uptake beyond our artisans workshop's needs will depend on fluctuating prices of charcoal and firewood, and the cost of labor to produce the bricks versus participate in other local economic pursuits such as rice paddy work, vanilla, and clove production.

Training local community members in water hyacinth biochar production in October 2025. (Photo: Mamy Ratsimbazafy/SEPALI Madagascar)

Test

Over the coming months, a pilot set of stoves that run on the invasive plant biochar bricks will be tested by a handful of individuals in home settings for daily meal preparation. We'll survey those users' experience before scaling further in 2026. "In 2024, we iterated 6 cookers. In 2025, we will construct 21," says Mamy Ratsimbazafy. With the right funding, the team hopes to begin to scale uptake in 2026.

Grow

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