Tomatoes inspire innovative green energy scheme
A tomato grower in Hertfordshire has found an environmentally sustainable way of heating his three acres of greenhouses, providing carbon dioxide for additional tomato growth, and producing sufficient electricity to power his local village.
Whilst most companies’ electricity use – often inefficient electricity use – results in emissions of carbon dioxide into the atmosphere, tomato growers need the carbon dioxide, and waste much of the energy by-product. Carbon dioxide is estimated to increase crop production by 20 to 30%, providing tomatoes with a greater resistance to temperature extremes and other stresses, better growth at low light intensities, better root/top ratios, less injury from air pollutants, and more nutrients in the soil as a result of greater nitrogen fixation.
Originally, Guy and Wright used gas burners hung up inside the greenhouses to produce carbon dioxide, but has since moved on to low sulphur kerosene boilers that also generate heat for the greenhouses. In the summer, the hot water produced by the boiler was stored in 100,000 storage tanks, and then pumped around the greenhouses at night. Around a quarter of the UK’s tomato growers use similar systems.
Now, Jones has converted the boiler to a gas turbine-driven combined heat and power plant, using ducting to pump heated air around the greenhouses. The air from the turbine is so clean that it would pass even California’s strict environmental regulations, he says.
And there is no danger to workers from the elevated levels of carbon dioxide, says Jones, as the computer-drive system prevents the level rising above 2,000 parts per million.
The bonus is that the turbine generates sufficient electricity for 500 homes, an idea suggested by electricity company Green Energy UK.
“I had planned to use the carbon dioxide we need for the tomatoes and some heat for our own use and was going to sell the rest to three businesses in our village, Green Tye,” said Jones. Following discussions with Green Energy, he changed his mind, and since the launch on 31 January, has become the UK’s only tomato grower producing green electricity.
There appears to be interest from the local village, particularly as Green Energy is offering shares in the company to its first 100,000 customers. “It would be nice to have some local customers,” Jones said to edie, welcoming the news that four villagers have expressed serious interest in taking up the Green Energy scheme.