Electricity from conventional power plant in Spain is 3100% more damaging to the environment than electricity from renewables, according to a recent report. It is the first time the environmental impact of Spanish electricity production has been quantified so exhaustively. The study was carried out by independent consulting company AUMA for eight Spanish institutions: the state-run renewables agency IDAE, renewables association APPA and national energy laboratory CIEMAT, together with the energy departments of five regions, Catalonia, Aragón, Basque Country, Navarra and Galicia. Data was compiled and processed over four years, comparing the environmental impact of the complete life cycle of seven power sources: lignite, oil, coal, nuclear, natural gas, small hydro and wind. The methodology -- used in similar studies in Holland and Switzerland -- assigns an increasing number of "ecopoints" in proportion to the environmental impact of each energy source. Wind came in second best, just after small hydro (table). Of the 12 impact categories, wind's least favourable ranking is in the heavy metal pollutants category, where it is responsible for 4% of the total produced by all seven sources. The study organisers intend to extend it to incorporate other technologies to provide "a working tool for defining national energy policy and objectives," with a view to the eventual internalisation of energy costs, says María Isabel Monreal, new director of IDAE.