Department for Environment, Food & Rural Affairs (Defra)  

Industrial sustainability experts from IfM Engage have collaborated with policy experts from Camrosh to deliver a report on current and future energy technologies deployed in food production, commissioned by the Department for Environment, Food and Rural Affairs (Defra).

The study explores ways to decarbonise controlled environment agriculture (CEA) whilst keeping it profitable and workable, so that growers can supply high-quality food to the British market in environmentally and financially sustainable ways. It also provides robust findings to inform investments in CEA and the associated technologies and infrastructure, highlighting that the right methods can help CEA contribute to greater food security and the UK’s net zero goal.

British agriculture comprises both traditional water intensive growing methods in open fields and horticultural operations such as controlled environment agriculture (CEA), some of which are highly energy intensive. The scope of the Defra report was to explore the potential to improve the sustainability credentials and feasibility of the latter. CEA is an umbrella term that covers several different horticultural sub-sectors characterised by their separation of crops from the natural environment, and their ability to control parameters like temperature, humidity, nutrients, and light. Glasshouses and polythene tunnels are the most well-known examples, but other types of set ups such as indoor and vertical farms are also emerging. While CEA is high yielding, water and land efficient, and historically allowed for cheap food production, it is energy intensive, and in the UK predominantly runs on natural gas-fired technologies. The findings suggest that CEA can contribute to greater food security, food affordability and the net zero goal when the following recommendations are followed:

• Energy efficiency measures should be encouraged throughout the sector, with a focus on integrating low/zero carbon energy supply systems into new CEA builds. The necessary technologies already exist for low carbon CEA and are largely proven.
• Support, including from policy mechanisms, is required for CEA to move forward in a low carbon manner. This presents a significant opportunity for the UK, and can have a positive impact on both local and national economies.
• Recommendations should be put in place now to facilitate the long investment horizons of CEA, typically 20-50 years. Current investments will impact the state of food production in 2050.

Background

Decline in numbers of CEA growers

Due to recent higher energy costs, in 2022, production from the sector reached its lowest level since recordings began 30 years ago. But because CEA has so many potential benefits – among them the ability to boost British food security and affordability – Defra recently commissioned a report on the gains, costs, feasibility, and scalability of current and future industrial horticulture models. The work was carried out by Dr Diana Khripko and Dr Samuel Short from IfM Engage and Dr Bernhard Strauss and Dr Pantea Lotfian from Camrosh, and the report was published in December 2023.

“Defra’s agri-food evidence programme supports the productivity, environmental sustainability, risks and trade-offs of farming systems. This study was commissioned to provide context around opportunities and barriers to the sustainable growth and development of the horticulture sector. Whilst it is clear from the report that there is no silver bullet, the information and data collated and disseminated will be of great use as the sector looks to further decarbonise, whilst facilitating further resilience and productivity opportunities.”                                                                                                        Statement from Defra, 2023

Carbon-intensive infrastructure

As it is, the CEA sector has a considerable carbon footprint for its size, but the technologies it builds on do not inherently yield high emissions. Over the last couple of decades, growers in CEA have overwhelmingly relied on combined heat and power (CHP) energy generation in line with established policy. CHP is an energy-efficient technology that even allows many growers to sell electricity to the national grid. Carbon dioxide from the combustion process is often extracted to enrich the atmosphere in the growing operations by boosting photosynthesis. But at present, deployed CHP is primarily fuelled by natural gas and releases a great amount of captured carbon dioxide into the atmosphere. The challenge, therefore, is to ensure that the energy used to meet CEA energy demand comes from renewable energy sources by deploying low-carbon technologies, and that its supply is reliable. The report aims to clarify what the current energy demand of the sector is, what their requirements on deployment of alternative energy technologies are, and identify how current and future needs can be met.

Data used in the study were primarily retrieved from Defra, the Climate Change Agreement (CCA) scheme from National Farmers Union (NFU), and from publicly available documents such as academic articles, grey literature including white papers and government documents, and industry reports.

“One of the key challenges in defining energy transition pathways at the sectoral level lies in the requirement for a systems-thinking approach. The selected approach and underpinning tools need to enable a holistic evaluation of how altering the ecosystem, such as through incentivising a scaled-up adoption of a new technology, will influence and reshape the sector as a whole. Further level of complexity is given by a large number of stakeholders, who have different capabilities and interests that can benefit the transition. Consequently, formulating a methodology that fosters their buy-in to the final outcome by involving them in a multi-stage consultation process was crucial for the overall success of the project,” says Diana.

A broad range of energy efficiency measures were reviewed in the study, including:

• Maintenance and operations management (enhanced routine maintenance and repair, and operations monitoring and control systems);
• Equipment optimisation (high-efficiency pumps and motors, high-efficiency boilers/other thermal energy generation, improved ventilation and cooling systems);
• Building/glasshouse structure and materials (system insulation, thermal screens, novel glazing technologies, and closed/semi closed glasshouses);
• Energy storage (diurnal thermal energy storage, and seasonal thermal energy storage solutions);
• Enhanced crop production (Optimised LED lighting duration and wavelengths, CO₂ management, and selective crop breeding/genetic modification).

Evaluated energy generation and conversion technologies included CHP and boilers fired by alternative fuels, electrically powered technologies such as heat pumps and electrical boilers as well as heat recovery from waste heat and geothermal sources. These technologies were assessed on seven factors: technical feasibility, commercial feasibility; environmental performance; organisational requirements and capacity; suitability of existing policy, regulatory and fiscal incentives; societal value creation potential; and societal, consumer and retailer acceptance.

In following, the team evaluated the carbon saving potential and associated costs across the CEA sector for the priority energy efficiency measures and energy generation and conversion technologies. The report also provides insights into the alternative solutions for the provision of carbon dioxide.

Findings

Decarbonising the energy supply

Some CEA technologies require only a tenth of the water of conventional agriculture, but a great deal of energy to perform what the sun does naturally, so the key to more sustainable CEA lies in decarbonising the thermal and electrical energy supply it relies on.

The energy technologies needed already exist, so the report recognises that the obstacles to widespread use are overwhelmingly economic and political. The UK is ideally situated with access to renewable energy and necessary technology to become a major international player in the field, so growers need strong policy support to reduce the individual risks they run by investing in these growing technologies.

Clear policy needed for guidance

At present, the report recognises that there is no one-size-fits-all solution to decarbonising the sector. Different technologies require different solutions and infrastructure to meet electrical and thermal energy needs of the individual CEA operation, and policy must reflect this need for flexibility and facilitate for it. As an example, vertical farming requires less energy for heating than glasshouse-based CEA, and with a warming climate, the needs of the sector will start to include cooling as well as heating.

Attracting and encouraging CEA technology investment

Despite dwindling numbers overall, certain CEA technologies, in particular indoor and vertical farming, are growing in popularity for investors who perceive the practices as innovative technology ventures rather than agricultural techniques. In the UK, the authorities’ policy-encoded pledge to reach net zero by 2050 works as a driver for investment in sustainable practices. The policy framework for sustainable agriculture and horticulture, however, is too vague for many growers and investors to see CEA as a safe choice. They are hesitant to take the risks involved in adopting novel technologies without support and policy guidelines in place, hence the recent exodus from the sector.

If investments are made in CEA technologies that run on renewable energy, the report paints a positive picture of what role the UK CEA sector can play on the path to net zero. CEA can produce 10 to 20 times as much food on the same geographical footprint as traditional agriculture, and free up land for rewilding and other environmentally advantageous purposes. The technologies can also reduce the risk of crop failure due to environmental influences and they provide consistently high yields of food. To fully reap the benefits of decarbonisation, the report authors urge action now. Investment timelines in CEA are 20-50 years, so current policy will influence the state of British food production at the 2050 deadline for net zero.

“This study was based on extensive interaction with the industry to obtain real-world perspectives on the challenges and opportunities facing the sector,” says Dr Sam Short. “Low-carbon technologies exist and are already proven today, and we observed a willingness in the industry to embrace transformation, but there is a considerable lack of clarity and there are funding challenges on the pathways forward. This report provides insights to assist both industry and policymakers in enabling a wider deployment of low-carbon controlled environment agriculture.”

Dr Diana Khripko continues: “One of the radical differences in moving away from fossil fuels towards a low-carbon energy system is that there is no one-size-fits all technology or solution, not even within one sector such as CEA. A future-proof and effective transition pathway therefore requires a strategy that is flexible enough to embrace legacy and existing low-carbon technologies, and potential future breakthrough innovations to align different industrial practices and their specific requirements to locally available renewable energy sources.