I am standing on the wind-buffeted tip of the Strata tower, looking out through the blades of what appear to be an enormous propeller, at the London skyline and the green basin beyond. St Paul's cathedral, across the river, seems close enough to touch. It's the kind of view, and the kind of heroically stylised building, you would expect to see in some 1930s sci-fi movie: the perfect place for a hero and a villain to have a rooftop showdown.  At 147 metres, the newly opened Strata is London's tallest residential building. The nine-metre blades I'm standing beneath are housed in one of three wind turbines that crown this new tower soaring above Elephant and Castle, an area of the city not known for flashy penthouses. But Elephant and Castle is undergoing a massive, if slow, transition from a rundown miasma of noisy road intersections, underpasses and vast housing estates into what the Borough of Southwark hopes will be a £1.5bn model of inner-city regeneration.  The plan was first made public six years ago and work is unlikely to be completed before 2020. It's a colossal challenge, as well as an opportunity, and the £113.5m Strata, the first of three skyscrapers planned for here, is a symbol of the dynamism and energy the project demands. And that energy must, of course, be seen to be green. It's early days, but if the turbines work as planned, and aren't too noisy for residents in the pricey penthouses beneath them, they should generate 8% of this 43-storey building's energy needs. This is roughly enough to run its electrical and mechanical services (including three express lifts and automated window-cleaning rigs) as well as the lighting, heating and ventilation of its public spaces, which include an underground car and cycle park.  Strata is the first building in the world to incorporate wind turbines into its structure. Yes, the new Bahrain World Trade Centre in Manama, by the firm Atkins, also boasts three giant turbines, but these are set on steel struts connecting its twin towers, not part of the actual towers themselves. While I can vouch for the strength of the south-westerlies that will turn Strata's blades, whether its turbines will set a precedent for future British towers is less clear: this rooftop was exceedingly hard to construct, almost prohibitively so, every part of it having to be hauled up.  However, what the three fans do, without a doubt, is give Strata a striking profile. Whether you find this exciting, disturbing or simply over-the-top will be down to personal taste, yet it's no surprise the tower has been dubbed the Electric Razor, not just because of its whirling blades but also because of its black and silver lines that seem to pixellate upwards; Boris Johnson, Mayor of London, has called it the Lipstick.  So what do green experts think? "You've got to take your hat off to the design team for delivering a building that captures the imagination," says Paul King, head of the UK Green Building Council. "I doubt wind power will become a common feature in high-rise inner city projects, but without this type of bold innovation, how would we ever know? Developments like this show that sustainability is increasingly becoming mainstream. That's something everyone should celebrate."  Including the 1,000 or so people who have already moved into – or bought into – Strata's 408 flats (each boasting floor-to-ceiling windows). And there is a difference between the two. Nearly every flat was bought off-plan, before construction began, 50-75% of them by investors. This is a shame: the whole idea of the tower is that it should be a guiding light for new inner-city residential development. This is meant to be a home for local people, not a machine for property market profiteering.  Indeed, 25% of the flats, on floors two to 10, are "affordable homes", for those on incomes of less than £60,000 (in central London that kind of money won't guarantee a home of your own); meanwhile, a three-floor pavilion to the side of the tower has been given to council residents leaving the soon-to-be-demolished Aylesbury Estate, a 1960s housing complex seen by most as an enormous failure. Tony Blair made his first speech as prime minister at this estate, in a bid to show his government would care for the poorest elements in society.  To my mind, Strata's big propellers give the building the feel of an airship holding aloft the passenger cabins (or flats) below. Or perhaps it's more like an old-fashioned transatlantic liner with its complement of first-, second-and third-class passengers. I think of this as architect Ian Bogle, of London-based BFLS (formerly Hamiltons Architects), leads me through the tall, narrow lobby to the lifts that shoot silently up to the residential floors.  'You feel like you own the city'  The views are spectacular. Most front doors open directly onto gaping vistas of London, framed by giant windows. They are not for the faint-hearted. Bogle goes to open what looks like a door at the side of a window and I think he might vanish into the ether. As it happens, he's simply opening a perforated screen designed to let fresh air in. "We've tried to get as much daylight and fresh air as possible into the flats," says Bogle. "You certainly feel as if you own the entire city from up here."  Indeed you do. There are magic moments, too: way below, trains race in and out of buildings and seem to pass through the tower itself. It reminds me of the super-modern city drawn by Antonio Sant'Elia, the Italian futurist architect, shortly before the first world war. His Città Nuova was a dynamic, machine-like metropolis through which cars and even aircraft would pass, via openings in the buildings. His imaginings inspired film-makers, from William Cameron Menzie's Things to Come in 1936, to Ridley Scott's Blade Runner in 1982; they also resonated in city developments as dramatic and diverse as the Barbican, the Pompidou and the Hong Kong and Shanghai Bank. And they echo today in these views from the Strata tower, and in its mighty turbines.  But are they just a tokenistic green gimmick? Or will they propel us towards a new urban architecture, one that's cinematically thrilling and ecologically sound? Until its sibling towers rise and the redevelopment of Elephant and Castle is complete, it will be hard to properly judge Strata. Right now, it stands alone, a sleek silver sentinel, towering over the follies of the recent past.
It is the world's first skyscraper with built-in wind turbines. But is London's Strata a green gimmick – or the future? Jonathan Glancey takes to the skies