Investors Should Look At Naturally Lit Rather Than Energy Hungry Vertical Farming, Says Researcher
19 September 2018
by Gavin McEwan
The energy required for artificial lighting and climate control makes "vertical farming" much less sustainable than its alternatives for local city-grown produce, according to an expert in urban sustainability.
Writing in response to the recent opening of "the world's most technically advanced indoor farm" near Dundee, Andrew Jenkins, a research fellow at Queen's University Belfast's School of Natural and Built Environment, said: "Vertical farming currently requires a lot of energy, which will hopefully decrease over time as companies like Intelligent Growth Solutions make technical advances.
"But for the time being, the practice of vertical farming is still a long way from being a sustainable method of agriculture."
This is because the energy required for vertical farming "is much higher than other methods of food production", he said.
"For example, lettuces grown in traditionally heated greenhouses in the UK need an estimated 250kWh of energy a year for every square metre of growing area. In comparison, lettuces grown in a purpose-built vertical farm need an estimated 3,500kWh a year for each square metre of growing area."
Other urban growing formats using natural light currently offer a less energy-intensive alternative, he said, adding: "I am surprised that more companies are not considering and maximising the opportunities presented by naturally-lit urban environments.
"Although they can’t grow as much food, rooftop greenhouses need at least 70% less energy for each square metre of growing area than artificially lit vertical farms."
Manchester alone has 136 hectares of unoccupied flat roofs, accounting for one-third of the city’s inner urban area, he pointed out.