The Vatican is well versed in conversions, but there probably hasn't been something on this scale since its very own St Paul was on his way to Damascus: the world's smallest country has announced it is to spend €500m (£441m) building Europe's largest solar power plant.

Once the 100-megawatt plant opens in 2014, the Vatican will become an electricity exporter to Italy supplying enough power for the needs of 40,000 households. It is latest in a string of pronouncements by the Holy See – or should it now be known as the Holy E? – that suggests it is serious about improving its environmental legacy. (Although still no word yet on how it aims to tackle global overpopulation through its policy on forbidding the use of contraception. Or on whether it's having second thoughts about the wisdom of launching Vatican Airlines.)

Last year, 2,700 solar panels donated by the German company SolarWorld were installed on the roof of the Paul VI auditorium. SolarWorld executives have also recently talked about the notion of building a low-carbon, electric popemobile, which a Vatican spokesperson described as a "brilliant idea". Although the new solar project will go to public tender, SolarWorld's chief executive officer Frank Asbeck is reported to have said: "We're quite confident we'll get the job." Well, the Catholic Church has always been big on rewarding loyal devotion.

Perhaps the Vatican's most noted environmental announcement, however, was made last year when Bishop Gianfranco Girotti, the head of the Apostolic Penitentiary, updated the cardinal vices – the seven social sins – by stating that Catholics "offend God not only by stealing, taking the Lord's name in vain or coveting your neighbor's wife, but also by wrecking the environment". Let's hope that hell and eternal damnation can be avoided, then, by all this recent good practice when it comes to environmental stewardship. (There is one supplementary question I have about hell, though: if the damned are to be burned once the torturing is over, can they at least be classified as biomass?)