 It will take a technological revolution to build the green economy, but this is already under way Much of the technology necessary to create low-carbon prosperity is available or being developed - and costs are falling fast The guestion is whether Britain will be in the vanguard of developing and using it, reaping the rewards in exports and jobs, or whether; as often in the past, it will stumble along behind more far-seeing economies. In this - the second of seven pages sponsored by Shell under the editorial control of the Telegraph - leading figures describe how green technologies are taking root in such key areas as energy, transport, infrastructure and urban living. You can take part in the debate by contributing reactions and views online. By Geoffrey Lean  During its first 15 months, the Coalition Government has been grappling with a series of tough challenges: restoring sustainability to the public finances, rebuilding our economy and delivering our climate change commitments.  Conventional wisdom dictates that supporting economic growth is incompatible with cutting carbon. Like most conventional wisdom, this is way off the mark. But, although reducing carbon on its own is relatively easy, doing so while generating growth and spreading prosperity is a far tougher challenge: one requiring co-operation and commitment from both government and industry.  This is a challenge that this Government is tackling head-on. We are investing in the transport infrastructure and technologies that will help us build a dynamic, balanced economy, while achieving our goals for carbon reduction.  We have announced a major electrification programme to reduce the carbon footprint of our railways. Our plans for a national high-speed rail network would encourage passengers to switch from short-haul aviation to rail, while bridging the north-south divide and spreading prosperity right across the country.  and because, unlike our predecessors, we believe that the enemy is the carbon, not the car, we have also placed Britain firmly in the global vanguard of the green motoring revolution.  Thanks to the ground-breaking Plug-in car grant, which gives motorists a 25pc subsidy of up to ?5,000, new, ultra-low carbon cars are much more affordable.  We have set out a comprehensive electric vehicle infrastructure strategy that identifies how a national recharging network can develop in a way that is targeted, convenient and safe. and, through our ?30 m Plugged-In Places programme, a network ofvehicle recharging points is being established in eight areas across the UK- from homes and workplaces to streets, car parks, retail and leisure facilities - to allow us to learn how real consumers use public charging infrastructure.  Initiatives like this are paying real dividends in terms of growth and jobs. Major companies are now launching innovative low-carbon vehicles in Britain and being a launch market makes the UK attractive as a manufacturing location. So Nissan is building a plant to manufacture its electric vehicles and batteries in the North East - and others will follow.  Meanwhile, Chargema 