While Europe redefines its energy matrix, local innovation is finding ground-breaking solutions where nature and technology converge. In this scenario, Ávila has become a living laboratory for one of the most promising techniques in current climate engineering: carbon mineralization.
Smart Green Minerals is a project driven by the city of Ávila involving the City Council itself, the Catholic University of Ávila (UCAV), and a large multinational company based in the province. This three-way initiative aims to permanently sequester carbon dioxide (CO₂) through an enhanced weathering process. In other words, to turn it into rock.
A process with a strong RD&I focus that is framed within a broader transformation of the European energy model, where other technologies, such as renewable hydrogen, are called to play a key role in long-term decarbonization.
The initiative began to take shape in May 2025 with the application of basalt powder —a crushed silicate mineral rock— in different areas of Ávila. Upon coming into contact with water and CO₂, this material accelerates a natural geological process that transforms carbon into stable minerals.
"We spread basalt powder on several roundabouts to measure the impact in urban environments. When it comes into contact with water, it binds CO₂ molecules and permanently sequesters them in the rock geologically," explains Jaime de Jaráiz, president and CEO of LG Electronics Spain.
In a first phase, the project was executed on four roundabouts of the city, divided between control plots and test areas, where initially a kilogram of basalt per square meter was applied. After verifying that it did not generate visual impact or alterations in the urban environment, the project expanded its scope in January 2026 to another four roundabouts, where the amount of material was increased to between three and six kilograms per square meter.
For now, researchers insist that it is still too early to talk about definitive results. "The enhanced weathering process takes time, and results should be observed after at least twelve months," notes Jorge Mongil, director of the UCAV research group. According to Mongil, the third sampling conducted after six months shows "slight increases in the soil's inorganic carbon content, as well as in carbonates."
The impact measurement is carried out through periodic soil analysis before and after the application of the basalt. The protocol includes four samplings: one prior to application, one immediately after, one six months later, and a last analysis upon reaching one year.
The city as a space for innovation
Ávila has thus become an open-air laboratory where it is possible to test whether this technology can work under real-world conditions. Beyond its environmental application, the project also explores a circular economy aspect. Part of the basalt used comes from TREMISA, a company in Ciudad Real that was already generating this material as a waste in the production of aggregates for asphalts.
"Smart Green Minerals turns this waste into a resource," explains De Jaráiz, who also highlights the possibility of replicating the model in other Spanish cities. Project development also required introducing technical adjustments throughout the process. After detecting that the initial increases in carbon were moderate, the researchers decided to increase the amount of basalt in new plots.
Ávila as an international benchmark
Ávila thus positions itself as a pioneering city in Spain in the urban application of mineral carbon sequestration, a technology that is gaining ground internationally. However, in Reykjavik, since 2007, the company CarbFix has managed to capture CO2 and permanently bury it in rock: How? It dissolves the carbon in water to then inject the resulting solution into underground basalt rock formations. This method accelerates the chemical reaction by releasing calcium, magnesium, and iron from the basalt, which combine with the carbon to form solid minerals. It thus mimics a natural reaction that would normally take millennia to occur, achieving 95% mineralization of the gas in a process of just two years, according to the results of the pilot project published in the journal Science.
Since 2019, the Zurich-based Swiss sustainable technology company Neustark has been working on the accelerated mineralization of carbon by injecting CO₂ into granules of recycled concrete sourced, for example, from the demolition of buildings, roads, and urban infrastructure. The gas is introduced into these crushed materials within controlled industrial facilities, where it reacts with the minerals present in the concrete and transforms into limestone within hours or days, becoming permanently sequestered.
Meanwhile, similar initiatives are also emerging in the United States, albeit using different methods. The California-based company Heirloom, founded in 2020, opened the country's first commercial Direct Air Capture (DAC) plant on November 9, 2023, in Tracy, California. Its technology accelerates the natural process through minerals derived from limestone that, due to their structure and porosity, are capable of absorbing CO₂ directly from the air. Once captured, the gas is concentrated for permanent under-ground storage or for use in industrial materials such as concrete. Currently, the plant has an initial capacity to remove up to 1,000 tons of CO₂ per year, according to the company's records.
While cities and companies around the world seek ways to advance decarbonization, Ávila has chosen to turn to soil as part of the solution. Thus, through innovation, parks, gardens, and urban spaces could also become active allies in further driving decarbonization.
