A New Dawn for Hydroponics – A Low Cost Sustainable Energy Solution
The innovative integration of technologies, delivering low-cost sustainable energy, can significantly reduce the costs of growing food in hydroponic/vertical farms.
Hydroponics and vertical farming (VF) are often seen as a potential solution to the global need to increase food production, but they are currently hampered by high energy and labour demands, high capital and associated emissions.
The UK currently imports a high percentage of food, especially food types which are currently either impossible to grow outside all year round or are just uneconomical to grow undercover, all year round.
This reliance on imports also means our food supply could be affected by changes to the economy or any global incident – as can be seen in the current Coronavirus pandemic.
The ability to economically and efficiently grow this type of produce “year-round” will mean less reliance on food imports, thus improving food security within the UK. There would also be the associated benefits of reduced emissions, lower transport costs and fewer food miles.
The case for wide-scale urban hydroponic/vertical farming is compelling but energy costs – and the potential for these to increase on a regular basis – and high operational running costs are significant barriers to the realisation of this goal.
In addition, within urban areas the demand for electricity, with demand for more EV charging points and power for heat pumps, is constantly increasing. This means it can be difficult to obtain or increase a grid connection and it is never a cheap exercise. Without a secure and consistent low cost OPEX base, vertical farming may never achieve the necessary cost savings needed to develop into the full commercial scale required.
There is however another way, an alternative which can address all of these barriers simultaneously.
At the heart of the solution is a state-of-the-art sustainable energy centre, which can deliver 2MWe (enough to power for about 1200 homes) of clean low carbon sustainable electrical power, along with either 3.5MWth of usable high temperature heat, or cooling, from the thermal conversion of a diverse range of post recyclate (the residue left once recycling has been completed and is usually destined for landfill disposal) wastes and biomass. This heat energy – both high temp heat 250-300˚C and low-grade heat 70-90˚C – could be used in district heating or Hydroponics or used for cooling via an intercooler/adsorption chillers.
The energy centre is able to receive a wide range of waste feedstocks and gasify them into a clean and consistent syngas which can then be used in a gas engine to generate electrical power. In addition the thermal conversion process also generates high temperature heat that can also be harnessed and used. Finally the process also generates CO2 which can be captured and used to enrich growing atmospheres.
This plant is capable of the recovery of more than 60% of the energy tied up in the waste. The technology is already being demonstrated at the Sustainable Energy Centre (SEC) in the West Midlands.
Our low cost sustainable power, heat for growing environments and cleaning (sterilising) and energy for cooling, will deliver a consistent low-cost OPEX base, allowing the sector the opportunity to break out and grow and experiment with new crop types; the current focus is on herbs and leafy and micro greens, as these are “relatively” easy to grow.
Sustainable energy systems have the potential to make it commercially feasible to produce “difficult-to-grow” high-value crops such as strawberries, year-round, in the UK, within carefully managed temperature- and atmospheric-controlled growing environments, all linked to and supported by cheap low-cost sustainable energy.
There are already successful trials of berries being grown in this type of Controlled Environment Agriculture (CEA) in France but they are not yet commercially viable.
A combination of increased yields, reduced water usage, sustainable energy, zero soil usage and the opportunity to be located within urban areas – thus reducing associated food miles – can all provide several key advantages over traditional land agriculture, particularly with respect to reduced carbon-emissions. The crops will not be affected by climate change, local weather, land quality or water shortage issues, and will not therefore be subject to high market price swings. They will provide a consistent quality product at a consistent and steady price for consumers.
KEW is aiming to integrate a range of new innovations in the development of a circular system that uses sustainable heat to purify water used within the system, via an innovative (Intellectual Property protected) boiling system and recover nutrients, thus reducing water and electricity consumption and minimising wastage. The generated heat will also be used to create steam that can be used to sterilise growing areas to prevent crop disease and infection, negating the need to use chemicals and pesticides, and further minimising production costs.
In addition, a system for CO2 dosing, using CO2 drawn from the energy centre process, can be used within growing areas, to enhance the growing environment and positively influence yield.
With the UK in the process of leaving the EU, the agricultural sector is likely to see a shortage of qualified seasonal labour, placing both operational pressures and additional cost on the traditional agricultural sector. Work is also being done to develop a Smart Growing digital-based system. This will use sensors/vision systems and learning algorithms to continuously monitor and improve all of the complex interlinked variables that influence growing conditions, in order to increase yield and product quality. It will also be possible for growers to remotely monitor crops.
The ultimate aim is to increase yields at the same time as reducing costs and emissions, making the commercial expansion of “complex” indoor, year-round food production a viable and attractive option.