Planet Thanet?

Decades after agricultural developments in places like the Netherlands, it has been announced (http://www.guardian.co.uk/environment/2008/jun/11/greenbuilding.food) that the UK is finally to have a major development involving hydroponically-grown plants in Thanet (Kent). The 'Thanet Earth' development will include 7 huge greenhouses (each 140m long and 8m high with its own rain water reservoir and power-generating station) on more than 90 hectares fine agricultural land. The crops (including tomatoes, cucumbers and peppers) will be suspended from the ceiling, so they can be tended and harvested at waist height. The plants will be 'rested' in the late afternoon but will be subjected to bright lights (workers will need sunglasses) from midnight onwards. The development (funded by a consortium of Dutch growers and the UK's largest fresh produce supplier) is intended to increase the 'UK's' crop of salad vegetables by 15% over most of the year (by providing 'perpetual summer'). Thanet Earth appears 'green' as it is planned to be independent of local water supplies for about half the year, to limit visual impact of light at night, to contribute power to the national grid and to push some of the carbon dioxide generated by burning gas into the greenhouses for the plants to use in photosynthesis. In another sense, however, these features are largely driven by economic considerations. The developers suggest that other sites in the UK suitable for such developments (in terms of sunlight as well as gas, electricity and transport links) are strictly limited and do not expect such activities to dramatically increase. The burgeoning increases in the costs of gas and water may further slow similar exercises. Although such developments might appear capable of generating food efficiently on a smaller acreage of land than traditional agriculture (perhaps giving scope for other land use), the economics suggest that they will not feed an endlessly increasing world population. The resources (in terms of what you have to put in) are still ultimately finite.