Breakthrough Energy Fellows Explorer Grants

Breakthrough Energy Explorer Grants cultivate the early-stage pipeline for innovative climate technologies.

Explorer Grants support research projects that are generally being conducted by a university lab or research entity but require further technical exploration before they would be ready to join the full-time Fellowship. These 12-month, one time grant awards may become eligible for a full-time Fellowship if the technology advances during the grant period.



Ammonia is a key molecule in our society. Through its use as fertilizer, it feeds more than 50% of the world. However, since its production commonly uses fossil fuels as a source of energy and feedstock, it is responsible for approximately 2% of global CO2emissions. For each ton of ammonia produced, three tons of carbon dioxide are emitted, making ammonia production one of the most polluting chemical processes in the world.

AmmPot is developing a single-vessel ammonia production process using exclusively renewable energy, air,and water. This new technology integrates catalytic synthesis of ammonia with its separation via absorption into a single vessel and includes a novel heat transfer approach to increase energy efficiency. As a result, AmmPot enables small-scale ammonia production under milder conditions to cope with the intermittencies of renewable energy, for itsuse as both green fertilizer and long-term energy storage vector.

AmmPot is led by Dr. Collin Smith and Prof. Laura Torrente, basedin the Department of Chemical Engineering and Biotechnology at the University of Cambridge (United Kingdom).


Long-duration storage allows for the use of more variable renewable energy sources (VREs) like wind and solar power by storing energy for a long period and dispatching power at times, such as during the night or on windless days, when these VREs are less available.

Cellcius is developing a potassium-salt based heat battery which can be charged with low-temperature waste heat, store the energy, and later release it as high-quality heat. By using abundant elements and a simple looping system, Cellcius can significantly reduce the overall energy storage costs.

Cellcius is led by Olaf Adan and based in Eindhoven, the Netherlands.

Minus Materials

Concrete is the most widely used resource in the world after water, and the production of cement –the main component of concrete –is one of the biggest polluters on the planet.

Minus Materials is engineering algae that convert CO2 and calcium into limestone for clinker, the binding material in Portland cement. This process exactly replicates traditional limestone, which was created by photosynthetic microalgae forming calcium carbonate shells that eventually turned into limestone deposits, on a much faster timeline and eliminates CO2 emissions in the production process.

Minus Materials is led by Wil Srubar and Sarah Williams and based in Boulder, Colorado.


Removing carbon dioxide already in the atmosphere is essential to achieving carbon neutrality by 2050 and is especially important for combatting emissions from hard-to-abate industrial sectors.

RockFix is developing methods to sequester CO2 permanently by mineralizing carbon into mine waste (“tailings”) to create negative emissions, recover critical minerals, and reduce the long-term liabilities of mine tailings that threaten rural communities. The team’s process involves accessing more calcium and magnesium ions in the mineral separation process to improve carbonation efficiency and scalability. RockFix also aims to empower mining communities to be part of the climate solution.

RockFix is led by Gustavo Marquez, Melissa Zhang, and Allen Liang, and is based in Stanford, California.

Thin Air Fuels

Hydrogen energy has the potential to reduce emissions across many hard-to-abate sectors – from steel and ammonia production to shipping and long-haul trucking.

Thin Air Fuels is developing a system that uses direct air electrolysis to produce green hydrogen directly from the air – even in low humidity. By avoiding condensation and evaporation of water, this system will allow hydrogen production in areas with high renewable energy potential but low water resources.

Thin Air Fuels is led by Dr. Gang Kevin Li and Jining Guo and is based in Melbourne, Australia.

UjuziKilimo Solutions

The agriculture industry currently accounts for 19% of global greenhouse gas (GHG) emissions. Soil and nutrient management systems designed to improve soil health can also aid carbon sequestration and reduce GHG emissions.

UjuziKilimo Solutions is developing an Internet of Things (IoT)-based sensor technology, called SoilPal, to monitor soil macronutrient levels, electrical conductivity, and pH and moisture content. The insights from SoilPal will help farmers optimize agricultural inputs such as fertilizer, seeds, and others and adjust irrigation to minimize water usage and carbon footprint while increasing efficiencies and crop yields.

UjuziKilimo Solutions is led by Brian Bosire, Dickson Ayuka, and Evans Wadongo and is based in Nairobi, Kenya.

Unnamed Redox-Flow Battery

Long-duration storage allows for the use of more variable renewable energy sources (VREs) like wind and solar power by storing energy for a long period and dispatching power at times, such as during the night or on windless days, when these VREs are less available.

Louise Berben is developing a Redox-Flow Battery (RFB) that uses an organo-aluminum analyte molecule rather than the traditional Vanadium as the charge carrier. In addition to being less expensive and domestically sourced, organo-aluminum can be used in non-aqueous systems, which increases the scope of real-world applications.

Louise Berben leads this project and is based in Davis, California.