A research programme at SRUC, Scotland’s rural university college in Edinburgh, is looking to develop a ‘vertical farm’ powered by waste from indoor livestock production.
A feasibility study has already demonstrated that waste bedding from cattle housed indoors can be processed in an anaerobic digester and the resulting biogas used to provide energy for a vertical farm unit – the main aim being to help livestock farmers reach the industry’s ambitions for ‘net zero’ emissions. The study suggests such a system has the potential to capture and use the equivalent of almost 240 tonnes of CO2 per farm per year as well as providing farmers with an additional source of income from the crops produced.
A new grant of almost £3 million from the UK government’s Net Zero Innovations programme will see a demonstration facility built at SRUC’s farm, in partnership with a number of research and commercial organisations including vertical farm system supplier Saturn Bioponics and two supermarkets. The carbon-emission savings that can be made and aspects of the vertical farm’s productivity will be monitored over the next three years. The system is expected to be ready for commercial uptake by the end of the project.
The unit will house 100 of Saturn Bioponics’ vertical hydroponic columns in a small polytunnel. A variety of crops is likely to be tested, starting with a range of leafy greens.
Saturn Bioponics estimates butterhead lettuce grown in its system yields around 7.66kg per sq m per crop cycle. The company estimates heating the unit to a minimum of 5°C from October to April will require the equivalent of 850,000 kW of heat input per ha and says for most crops supplementary light won’t be needed.