Abandoned coal mines across the UK could be brought back to life as huge underground farms.
According to work being done at the University of Nottingham in the UK, unused coal mines could be re-purposed and used as underground farms. With the ever-declining demand for coal around the world, there are over 150,000 coal mine shafts that are abandoned in the UK alone – but they might soon be given new life in the form of ultra-efficient indoor farms.
Subterranean farms is an alternative approach to large scale crop production, which its advocates say improves food safety, yield and cost efficiency. President of the World Society of Sustainable Energy Technology, Prof Saffa Riffat, believes the scheme would be a cost-effective way of meeting the growing need for food.
Though it might seem counterintuitive, coal mines are actually an “almost perfect” environment for farming. These underground tunnels naturally maintain consistent temperatures, and they are unaffected by weather changes, seasons, or the unexpected symptoms of climate change. Furthermore, vertical indoor farms use up to 95% less water than regular land farming and no pesticides.
In the UK there are over 1,500 redundant coal mines, and in China, there are over 12,000 abandoned coal mines (0.6 million m3).
In a former air-raid tunnel in London, scientists Richard Ballard and Steven Dring are testing their plans for future underground farms, and they are already seeing immense potential in their work. The repurposed World War Two bunker is currently providing healthy vegetables to supermarkets of the Clapham Common neighborhood, all while avoiding the dynamic – and sometimes harmful – weather conditions that most farms encounter on the surface.
Thanks to the success of their undertaking, the concept is being expanded to abandoned coal mines in the UK. The proposal has already garnered support from scientists and economists alike, as they foresee this venture as a means not only to provide a sustainable harvest, but as a measure that would create jobs in areas that have lacked economic stability since the closure of the mines.
“A lot of hill farmers in Wales are living hand to mouth so anything that helps diversity and brings a new form of income would be very welcome,” Land Trust Chief Executive Euan Hall told BBC.
Research regarding the new farming technique shows that, given the proper allocation of resources and farm design, coal mine farms can successfully generate up to ten times more food than surface level farms. This means that less land would need to be allocated to farmland, which would in turn drastically reduce greenhouse emissions and deforestation, as agriculturalists could use carbon-capture technology to trap and utilize the crop’s natural CO2 emissions.
Crops would either be grown in water or suspended in the air and sprayed with water and nutrients. The technique could also result in the revitalization of many species that are endangered by farming practices.
A variety of crops could be grown in the subterranean farms using hydroponic planters, which feeds plant root with nutrient-rich water. Coloured LED units would enable photosynthesis in the absence of sunlight. In an underground environment, groundwater could be used directly or water could be condensed from ambient air.
Carbon dioxide (CO2) is required for plant photosynthesis, and the subterranean farms will use CO2 capture and release systems, as these spaces are well suited to carbon storage.Use of carbon capture systems has the added benefit of reducing CO2 concentration in the environment, as additional carbon is adsorbed in materials in the subterranean space.
A spokesperson for the Coal Authority said it was "open to considering new ideas" as part of its innovation strategy. "I wish I had thought of this idea when they were making all the miners redundant. We may have been able to offer them an alternative job."
He added: "As an organisation, we constantly review new ways to develop our mining legacy in an effort to minimise remediation costs, generate income from by products and create a future for these important and unique areas".