Halifax-based Planetary Technologies has cracked the top 20 finalists for the US$100 million Carbon Removal XPRIZE startup competition, building on a prior, $1 million interim award the company won in 2022.

Founded in Ottawa in 2019, Planetary has developed a system to convert alkaline rocks left over from mining operations into a substance called bicarbonate, which it plans to release into marine environments to counteract ocean acidification and chemically extract carbon dioxide from the atmosphere.

Inspired by the Orteig Prize that Charles Lindbergh won for completing the first transatlantic flight in 1927, the Carbon Removal XPRIZE is funded by Elon Musk’s foundation and drew more than 1,133 entrants.

“It takes a village (and then some) to solve the world's biggest challenges,” wrote Planetary CEO Mike Kelland in a social media statement.

“I'm so excited to be part of this incredible group of carbon removal innovators and to be moving on to the next phase of this competition.”

Planetary’s process is the brainchild of Chief Technology Officer Greg Rau and creates hydrogen as a byproduct, which the company sells, as well as carbon credits. The company’s inclusion in the top 20 shortlist comes less than a month after it cracked the top 100.

“It is an incredible honour to be included, but I want to highlight the geographic and pathway diversity of this top 20 group,” wrote Omar Sadoon, Planetary’s Director of Procurement. “(There are) so many different countries … Then you look at the variety of solutions being brought forward for each of the four categories (Air, Rocks, Land and Oceans) and it becomes clear that climate innovators are just beginning to battle test an array of solutions in the fight against climate change.”

Planetary was also one of the five startups chosen to pre-sell carbon credits to Toronto’s MaRS Discovery District under its Mission From Mars program.

The pre-purchase deals will involve MaRS receiving the credits gradually over the course of the next three years, as the companies work to implement their nascent technologies. Although MaRS did not reveal the value of the individual purchase agreements, it said in a statement it is buying credits worth a total of 84 tonnes of carbon dioxide, roughly equivalent to the production of 19 passenger vehicles.

Nor is Planetary the first East Coast company to make a strong showing in an XPRIZE. In 2021, fellow Halifax startup CarbonCure Technologies was one of two businesses to split the first prize in the initial Carbon XPRIZE, which offered US$20 million to the winners.

CarbonCure's system for curing concrete with carbon dioxide is also being used by Brisbane, California-based Heirloom Carbon Technologies, another of the current top 20, to demonstrate its technology for the judging panel of 70 internationally recognized climatetech experts.

Founded in 2020, Heirloom has developed a system for using limestone to sequester atmospheric carbon. And last year, the two companies jointly said they had successfully sequestered atmospheric carbon dioxide in concrete in what they described as a world first.