The world's darkest skies, a treasure trove for astronomers, have been saved from an industrial megaproject in Chile. The proposed green hydrogen and ammonia project, which threatened to cause 'irreparable damage' to the clearest skies in the world, has been cancelled. This decision comes as a relief to astronomers and environmentalists alike, who had raised concerns about the project's impact on light pollution and the performance of advanced astronomical facilities. The European Southern Observatory (ESO) and the Gran Telescopio Canarias were among the organizations that advocated for the preservation of the region's pristine skies.
The project, known as INNA, was set to cover over 3000 hectares in Chile's Atacama Desert, just a few kilometers from the ESO's Paranal Observatory, one of the world's most important astronomical research sites. The ESO's own impact assessment revealed that INNA would increase light pollution by at least 35% near the Paranal Observatory and by more than 50% above the southern site of the Cherenkov Telescope Array Observatory (CTAO). Once built, the CTAO would become the world's most powerful ground-based observatory for very high-energy gamma-ray astronomy.
The ESO's director general, Xavier Barcons, had warned that the hydrogen project would pose a significant threat to the performance of the most advanced astronomical facilities anywhere in the world. However, on January 23, AES Andes, the US power company behind the project, announced that it would discontinue plans for the INNA complex. The firm cited a focus on renewable energy and energy storage as the reason for this decision. This move was formally confirmed when AES Andes sent a letter to Chile's Environmental Assessment Service requesting that INNA not be evaluated.
Barcons expressed relief at the decision, emphasizing the urgent need for clear protection measures around astronomical observatories. He also noted that green-energy projects can be fully compatible with astronomical observatories as long as they are located at sufficient distances away. The director of the Gran Telescopio Canarias, Romano Corradi, shared this sentiment, expressing delight at the cancellation and hoping that global pressure to defend dark skies played a role in the decision.
