Famous entrepreneur Elon Musk is funding ideas to reduce greenhouse gas emissions by funding algae farming and artificial limestone production.

SpaceX rocket company and Tesla electric vehicle developer are sponsoring $100 million XPRIZE carbon removal competition. This competition will look at the most promising ways to reduce the atmospheric carbon dioxide.

Friday’s announcement of the 15 early-phase “milestone round” winners was a great boost for teams looking to continue and scale up their work. Each team will receive $1 million.

“What we have said is that you haven’t given us one million dollars; what you’ve done is catalyzed investments in this technology,” stated Mike Kelland, CEO at Planetary Technologies. This milestone winner seeks to increase ocean’s ability to absorb carbon dioxide through controlling seawater’s rising acidity.

The $80 million final prize money will be distributed in three years. However, the milestone winners are not necessarily in the lead or in the best position to win it. Anyone can still participate in the contest that was announced one year ago and possibly get a piece of that money until Dec. 1, 2023.

The winner or winners will have to demonstrate that they can remove 1,100 tonnes (1,099 metric tons), of carbon dioxide each year. They also need to show how much it would take to remove up to 1 million tons (1,1 million metric tons) annually and a pathway to removing billions more tons per year.

The work submitted for the grand award will be validated by an independent party, which is not the participants or XPRIZE. It will be announced on April 20, 2025.

XPRIZE awarded $5 million to student teams in the carbon removal project category last fall. The milestone winners announced Friday offer a range of methods to remove carbon dioxide using artificial methods and by allowing nature to do most of the work.

Planetary Technologies doesn’t look up at the sky, but instead down at the ocean to reduce atmospheric CO2. Canada’s Dartmouth, Nova Scotia-based company plans to use leftovers from metal mining to increase the ocean’s ability to absorb the greenhouse gas.

Kelland stated, “If we ignore the ocean — let’s say we try to do this on the land, and we’re trying store it in ground — it’s just not going to happen.” That’s the opinion of many scientists who work in this field.

8 Rivers Capital in Durham, North Carolina, believes ocean chemistry is a good example of what can be replicated. The winner company will trap atmospheric carbon dioxide within calcium carbonate crystals. This is similar to how seashells and limestone are formed by the gas.

Adam Goff, spokesperson for the company, described the process as poetic in a certain way.

“The calcium cycle regulates the earth’s CO2 over many millions of years. Goff stated that we are speeding up this natural cycle.

Global Algae is a California-based company that cultivates algae for rain forest restoration. Mark Hazlebeck (a principal in the family-owned business) said that algae could be more efficient and profitable than cattle ranching, soy and palm oil cropping currently on cleared rain forest land.

Hazlebeck stated that “We are actually creating more oil, and protein, while we’re also reforesting.”

The announcement of the prize comes as the United Nations Intergovernmental Panel on Climate Change continues to warn in increasingly dire terms about the danger of rising global temperatures including worsening heat and storms.

“We need more, more and deeper emission cuts, as well as more reliable and validated carbon removal strategies. Marcius Extavour is chief scientist and vice-president of climate and environment at XPRIZE.

XPRIZE is a technology promotion group best known for a 2004 contest encouraging the development of a private-funded, reusable spacecraft. Two teams who demonstrated that they could trap carbon dioxide in concrete and make it profitable from smokestacks won a $15 million XPRIZE prize.

In a 2021 chat with Musk, Peter Diamandis , XPRIZE founder/executive chairman, stated that even if we stop CO2 production it’s likely still not enough. “We need mechanisms to extract CO2 from the atmosphere, and oceans. These don’t exist at the moment.”

Musk responded that the risk of climate catastrophe could be “dire” if higher greenhouse gas concentrations continue to rise alongside human population growth.

Musk stated that it was probably an unwise experiment to conduct. “Right now we only have one planet. Why take that risk, even if there is a 0.1% chance for disaster? It’s crazy.”