Controlled environment agriculture (CEA) within industrial-scale greenhouses could make the UK a significant exporter of horticultural produce within ten years, a review of the sector – published by Defra and produced by Camrosh Ltd and the Institute for Manufacturing Engage, University of Cambridge – has concluded.
The Foresight study, compared the relative gains, costs, feasibility, and scalability of current and future ‘industrial horticulture’, including greenhouses and vertical farms. It comes at a critical time for the sector.
CEA has huge potential to increase UK self-sufficiency. It produces 10 to 20 times the volume of food from the same land footprint as field-grown crops while using less than 10% of the water resources required for open field growing, and there is potential to further improve productivity.
The report proposes that the UK has both the climate and the renewable energy resources to be a major global player in low carbon CEA food production. This vision is supported by reports of a decline in field production in other geographies – for example, an EU report predicts Spanish tomato production will fall by 20% by 2030 – indicating that an expansion of domestic CEA would contribute to food security.
However, the sector runs almost entirely on natural gas-fired combined heat and power (CHP) and has been badly hit over the past three years by the increase in fuel prices and by a shortage of labour. This has led to production falling to its lowest level in 30 years, with many producers scaling back out-of-season growing or shutting down permanently.
Dr Bernhard Strauss is Director of Research at technology strategy consultancy Camrosh. In collaboration with IfM Engage, University of Cambridge, he is a co-author on the report. He comments: “The report comes as the CEA sector is at a crossroads on the journey towards net-zero. The UK has a choice: to actively support and build a CEA sector, or risk losing ground and seeing the industry fall into decline.”
The researchers consulted a multi-disciplinary group of experts and stakeholders across the CEA sector, and the authoritative report provides an in-depth analysis of the current situation and the opportunities offered as well as the challenges of a number of alternative and renewable energy supply solutions. In addition, the role of various agri-tech innovations in the sector for reducing energy demand is discussed.
Co-locate with renewables to enable sector to scale
Intelligent Growth Solutions (IGS) is a vertical farming technology company that has recently announced a project in Dubai, which aims to replace 1% of the country’s fresh produce imports. Business Development Manager Andrew Haxton says this illustrates the potential of the sector, if CEA is located close to renewable energy production and it is possible to plug in with a private wire and not rely on the grid. “For the energy producer and the grower, this offers much greater price stability, the key is to scale-up.”
Although strongly emphasising the role of alternative energy sources in the transition to net-zero, the report warns that ‘one size doesn’t fit all’ and advises that the design of an appropriate energy system is strongly dependent on the energy demand profile of the crop and the production facility.
The study uses ‘Marginal Abatement Cost Curves’ (MACC) analysis to present six alternative scenarios of the future to provide illustrations of the technology roadmap required to transform the sector towards net-zero by 2050.
The MACC visualisation technique enables policymakers and industry to make informed decisions about which technologies and measures are most cost-effective in terms of boosting productivity whilst reducing energy usage and greenhouse gas emissions.
Technical solutions already here
The technical solutions that would enable CEA to transition to low carbon production are already available today, the authors observe, so the challenge is no longer technical but rather an economic and political issue, coupled with the need to achieve economies of scale.
Future Biogas is one of the largest producers of biomethane in the UK; Business Development Director Dr Becky Wheeler comments: “At a time of climate crisis, there has never been a more urgent need for cross-sectoral and multidisciplinary collaboration to decarbonise food production and increase food security. With the right economies of scale, policies and regulatory support, the AD industry could play a significant role in supporting the CEA sector.”
Joined-up Government policy needed
The report concludes that many energy efficiency measures – such as installing thermal screens, improving monitoring and control systems, and enhanced maintenance – require low investment and could significantly reduce energy consumption in the short term. However, to transition to a low energy, low carbon future requires joined-up government policy and incentives for long-term investment.
India Langley of LettUs Grow Ltd agrees: “We need a joined up national policy to make investment in renewable infrastructure easier and far more attractive.
“We often think about financial incentives, but an important part of this is planning policy levers around enabling that co-location. It is not uncommon for commercial growers to get planning permission for a new glasshouse but be unable to build because they can’t get planning permission for the solar farm on the field next door.
“There are imbalances in the planning sector that could be addressed to try and tie some of these co-located and valuable opportunities together so that they don’t just get stuck within the system.”
Recommendations from the report include:
Gain economies of scale – efficiencies increase with larger facilities, particularly if co-located close to sources of renewable energy production or when investing in the latest high-tech greenhouse innovations. The UK currently only has 50 large growers with over ten hectares and a further 50 medium-to-large growers. Expanding the land area dedicated to CEA is recommended by independent experts.
Optimise energy usage – Next Generation Growing (NGG) is already the industry standard in the Netherlands, seeing the integration of control systems to maximise plant growth and yield while minimising heat and energy consumption.
Technologies including wireless sensors, vision systems, the Internet of Things, digital twins, AI, and others can provide real-time automated monitoring and continuous adjustment of temperature, humidity, CO2, air circulation, light, nutrient supply, and alerts for symptoms of fungal disease to optimise growing conditions and yields.
Equipment optimisation – the report observes that switching lighting to high efficiency LEDs will reduce energy consumption whilst enabling the potential to ‘tune’ the colour spectrum to maximise photosynthesis and other physiological functions, thereby boosting crop performance.
Renewable energy sources – a number of alternatives are discussed in the report and the advantages and obstacles assessed. A conclusion is that of greatest value are integrated solutions using more than one energy source, where businesses can also generate their own renewables, or hot-wire from a co-located source. More extensive use of renewable electricity for heat pumps in combination with biogas from anaerobic digesters for heating could be another combination to help move forward on the path to net-zero. However, challenges are often not technical, but rather financial, regulatory, or political to get such approaches off the ground at the necessary scale.
Potential technologies include:
- Agrivolatics – growing crops beneath transparent photovoltaic panels, thereby generating energy and food. However, solar power requires battery storage as the requirement is greatest during periods of low irradiation; therefore, the cost and maturity of battery technology is an obstacle at present.
- Anaerobic digestion – decomposition of waste organic material or energy crops to create biomethane. This can be used to replace natural gas for CHP units and boilers and supply CO2 for plants. However, AD production needs skilled staff and economies of scale. Where co-location may not be possible, gas could be sleeved throughout the existing network.
- Hydrogen – this is a complex proposition and viable only at scale once the required infrastructure and markets have become much more mature.
- Heat recovery – transfer of thermal energy using a phase-change fluid or refrigerant gas. Offers matching of cooling/heating, for example to keep a packhouse cool while a greenhouse warm. However, bespoke solutions are often required so the costs for larger installations are high.
- Geothermal – used to some extent in other European countries, such as Germany or Austria, after the Netherlands pioneering its use on a large industrial scale for the horticulture sector with an ambition to provide 65% of its CEA energy demands by 2050. It is a relatively mature technology, however the initiation costs are high, and operations would need to be coupled in most instances with other large power users to make it commercially viable
Consider diversification to increase profitability – there is a strongly growing market for high value medicinal plants, such as cannabis, and the plant-based production of vitamins and other active ingredients; however, these will not contribute to food security.
Precision breeding – gene editing technologies could be used to develop new crops that might thrive in cooler growing conditions, which would reduce energy consumption. Although using this technology to find the traits for commercial and environmental success can be a lengthy process, first successful field trials in the UK have already shown very promising results and its potential for the future.