In 2000, Barcelona became the first European city to implement a Solar Thermal Ordinance (STO), making it compulsory to use solar energy to supply 60 percent of running hot water in all new buildings, renovated buildings, and buildings changing their use, independently of whether they are privately or publicly owned. The STO is part of Barcelona’s long-term strategy, integrated in a political and planning framework for climate change mitigation, to achieve energy self-sufficiency in the long term through the promotion of energy efficiency and the use of renewable resources. In addition, Barcelona offers a housing tax incentive for voluntary solar (thermal or photovoltaic) installations, regulated by the Municipal Fiscal Ordinance. The incentive provides a 50 percent tax reduction for four years after installation.

The STO applies to buildings that are intended for residential purposes, health, sports, commercial, industrial, and any other use that entails the presence of dining rooms, kitchens or collective laundries. With the approval of the Barcelona Environmental Ordinance in 2011, the scope was extended to require the use of solar energy (photovoltaics) for electricity generation in the design of new and renovated buildings.

The approval of the STO has created new market opportunities. Requests for the installation of solar thermal systems has increased, and so has the total surface area of solar thermal systems in the city from 1,650 square meters (over 1 square mile) in 2000 to 87,600 square meters (54.4 square miles) in 2010, increasing the licensed surface by a factor of more than 50 times. This has created projected energy savings of over 11,200 MWh per year, and resulted in a reduction of greenhouse gas emissions of approximately 1,970 tonnes (2,171 US tons) of CO2 per year, further contributing to Barcelona’s energy independence. More than 50 other Spanish cities have replicated the ordinance.

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This article was adapted from our latest book, “Sharing Cities: Activating the Urban Commons.” Download your free pdf copy today. This article was co-written by Ana Marques (ICLEI), Toni Pujol (Barcelona City Council) and Emily Skeehan.