From coal to solar energy. Clean, renewable, practically limitless. It is the perfect example of an energy transition: the town of Holyoke in Massachusetts, where an old coal plant, the Mount Tom power plant, has been transformed into a solar park made up of 17,000 photovoltaic panels with the largest energy storage system in the US state.

The coal plant, owned by Gdf Suez, now Engie, had been operating for at least 50 years, polluting the town's air and causing various respiratory problems, with asthma rates twice those of the rest of the country. But from 2010 onwards, a group of residents working with the association Toxics Action Center began lobbying for the plant to be redeveloped into a solar park.

Power to the people

What made the town's energy transition possible was the activists' ability to engage in dialogue with residents and, above all, with the plant's workers. In this case, they worked alongside the trade union to also develop a plan for retraining workers, so as not to have a negative impact on the community.

After the plant's permanent closure in 2014 — already in crisis due to falling coal prices — the company installed the first solar panels in 2017, and last year the 3-megawatt storage system, which will allow electricity to be supplied to over 2,000 households even at night.

From a coal plant to solar, Holyoke's choice

Today the town's electricity comes 100 per cent from renewable sources, much of it from hydropower. The solar plant has in fact been integrated into the energy mix, and the storage capacity makes it possible to manage peaks in demand — for instance in summer, when air-conditioning use intensifies.

Massachusetts is one of many US states at the forefront of energy and climate policy, despite the well-known positions of President Trump. Last 12 December, Governor Baker signed the Comprehensive energy plan (Cep), a plan that aims to achieve a "clean, affordable and resilient" energy future by 2030.