Solar Obligation in Barcelona: Pioneers in Europe

The Barcelona Solar Thermal Obligation was the first of its kind adopted in a large European city. The first version entered into effect in August 2000. The revised version was approved in February 2006. Main changes are that the regulations now apply to more buildings and that the solar fraction was increased.

The obligation applies to new buildings, buildings undergoing complete rehabilitation and to those undergoing a change in use. The Catalan example has been adopted by more than 50 cities and municipalities in Catalonia and in the rest of Spain. Among these are the provincial capitals Madrid, Sevilla, Granada, Burgos, Pamplona and Valencia.

Before passing the law, 1,650 m² solar collectors had been installed in Barcelona. This corresponds to a surface of 1.1 m²/1,000 inhabitants. Until December 2005 solar panels with a surface of 31,500 m² were installed (22 MWth). In 2008 it was 40,095 m² (25 m²/1,000 inhabitants). The Barcelona Energy Improvement Plan (PMEB) sets the goal that about 96,300 m² of solar collectors should be operating in Barcelona until 2010.

This article was written by Ina Röpcke, a German journalist and solar thermal expert.


City / country


Barcelona / Spain 




Ordenanza Solar

(Barcelona Solar Thermal Ordinance) 




To promote and regulate the installation of low-temperature systems for collecting and using active solar energy for the production of hot water for buildings


(use solar energy to supply 60% of their running hot water requirements) 


Date when law passed


July 1999


Date when law came into effect


original version: August 2000

revised version: February 2006


Target group


  • new buildings or constructions
  • complete rehabilitation of buildings or constructions 
  • change in the use of the whole building or constructions 


Buildings covered are those intended for the following use: residential, health, sports, commercial (in special cases), industrial (if hot water is needed for the industrial process or if showers are to be installed for the staff), and in general any other use that entails the presence of dining rooms, kitchens or collective laundries


Special requirements


When planning the solar thermal system, the following minimal solar contribution has to be considered: 


  • Domestic hot water: the values specified by the obligation, according to the various demand levels (from a minimum of 60 %), for a reference temperature of 60 °C: general if the auxiliary source of energy is heating oil, propane, natural gas or other gas (general gas), or the Joule effect if electricity is the auxiliary source 
  • Industrial process heat at up to 60 °C: 20%. 


  • Covered swimming pools: 30 % 


  • uncovered swimming pools: 100 %




A complete exemption is allowed in the following cases: 


  • in buildings where it is not possible to cover more than 25 % of the hot water demand by solar thermal (in the non residential sector this exemption is valid only if the daily demand that can be covered by solar is not higher than 90 MJ) 


  • in non residential buildings with a daily hot water demand lower than 20 MJ


The solar fraction might be reduced in case 

  • the building has not sufficient access to the sun
  • of refurbished buildings if the previous configuration creates architectonical barriers 
  • the surface is not sufficient for the installation of solar panels
  • other renewable energies, cogeneration, waste or free heat are used for hot water demand. In these cases the solar system has to cover only the remaining demand for hot water. 



Last review of this tabloid


27 August, 2008


Further information




Barcelona City Council

Environmental Department Mr. Toni Pujol
Pl Sant Jaume, 1
08002 Barcelona, Spain
phone 0034 - 93 - 402 70 00




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