Irish climate tech startup Silicate is gearing up to undertake its first trial of enhanced weathering technology in the United States.

The Sligo company claims to possess cutting-edge technology capable of permanently removing carbon dioxide from the atmosphere and sequestering it in the world's oceans for tens of thousands of years.

The trial will involve spreading 500 tonnes of crushed waste concrete over 50 hectares of farmland, an area equivalent to 120 football fields, near Chicago. The milled concrete will then break down in the soil over the course of a year, kick-starting a process known as 'enhanced weathering'.

Essentially an accelerated form of natural chemical weathering which typically takes millions of years, enhanced weathering dissolves rocks into bicarbonate, isolating carbon dioxide from the atmosphere. This bicarbonate is transported into rivers and the sea, where it either remains in dissolved form or becomes locked into the seabed. 

An unconventional solution

Silicate takes this approach to the next level. The firm pulverises silicate rocks into powder, creating a higher reactive surface area and then spreading this dust on farmland. The key innovation is using concrete instead of rocks, capitalising on one of the world's largest waste streams. 

Silicate sources leftover concrete from construction entities and processes it before offering it to agricultural land, free of charge. Not only does this technique remove carbon dioxide, but it also enhances soil health and crop productivity.

How does the firm make money, you ask? Silicate measures the amount of carbon that has been removed and sells an equivalent amount of carbon removal credits to large corporations looking to reduce their own footprint

“We believe our approach of using returned concrete to both improve the productivity and carbon removal potential of farmland could be game-changing, as it is low-cost, it is safe to apply to agricultural land, and uses an abundant material that is easy to source,” said Silicate’s CEO and co-founder, Maurice Bryson.

The company expects its US trial to permanently sequester up to 100 tonnes of carbon dioxide from the atmosphere. The pilot program will also serve as a test of the technology's effectiveness in the American Midwest, where soil conditions differ from those in Silicate's native Ireland. The technology has already demonstrated "huge promise" in Ireland.

A promising future for climate tech

The startup estimates that its technology could have the capacity to remove between 50 and 100 million tonnes of carbon dioxide annually in this region alone. To put this into perspective, a typical passenger vehicle emits approximately 4.6 tonnes of carbon dioxide annually.

If the results of the US trial are favourable, Silicate is poised to expand its operations across Illinois and the Midwest, further accelerating its mission to combat climate change. 

The trial, funded by prize money from the THRIVE/Shell Climate-Smart Agriculture Challenge, will be closely monitored using LI-COR soil gas flux measurement devices provided by Shell. This monitoring will continue for the full one-year duration of the testing. 

This innovative approach to carbon removal underscores the vital role of startups and technology in addressing one of the world's most pressing challenges.