Finding the perfect solution to the latest energy price increases very much depends on the individual glasshouses and business, but savings can be made by making small changes, Adrian Tatum asks industry suppliers what growers can do to ease financial pressure on their business.
Kathryn Smethurst, Horticulture and Indoor Growing Manager for Priva in the UK says glasshouse growers have been hit by the ‘perfect storm’. “Almost everything you can think of that they use has risen in price. There isn’t just energy prices but so many different pressures-Brexit, labour, fertiliser prices, the price of steel etc. We are seeing a slight improvement now in comparison to early in the year, but not by much. Growers have had to make difficult decisions, to have the heating on, to turn the lights on or not even crop at all.”
She advises growers that one thing they can do to make some small changes is check their control systems on a regular basis. “It is small margins but right now every small change can help. By checking and tweaking existing control systems some savings can be made which can still maintain a high quality and profitable yield. Cloud based applications like Priva Operator can help in this by giving growers the flexibility to monitor and adjust settings on the go.”
She also says that Priva has worked hard in recent times to improve and complement the energy management strategies in the Connext climate computer. Examples of this are improved buffer and lighting control to ensure reduced gas and electricity consumption. Our consultants can also advise on the use of temperature integration over 24h, the use of screens, temperature balance in different compartments and which sensors are available or necessary to create the most efficient energy control. “Implementing small changes along with delivering tighter controls and reviewing things like the installation and screening can help as well,” adds Ms Smethurst.
“The other thing we are being asked to do is deliver more integrated systems, so we are future proofing for the next generation of growing techniques and to deliver further efficiencies. Projects using sustainably sourced heat (like heat pump technology), electricity, and waste CO2 from industry are growing in popularity.
Now is the time for Government to be really helping with these type of projects, because they are not only more efficient and lower carbon, but are the future of the industry. The sector needs to become more resilient when it comes to energy usage, because volatility in the markets will not be going away any time soon.”
Priva is in a strong position to help with this with its combined expertise in glasshouse environmental control systems and building automation. Their in-house team of consultants, experts in their fields in integrating the latest technologies, can support growers in the specification and delivery of successful projects like these.
Ms Smethurst says, “Priva has the technology, the expertise and we are trusted globally to do the best for our customers. It is our mission to make it easier to grow a profitable crop with a lower use of natural resources.”
For Charlotte Penn, Business Development Manager at Cambridge HOK, the biggest challenge long-term for glasshouses growers is managing C02. “The biggest challenge for growers will be managing CO2 output where it’s required for crops. One of the issues with heat pumps for example, despite the obvious advantages in energy savings, is that they don’t produce CO2 so growers have to buy liquid CO2 and both the environmental and financial savings are cancelled out. It is now more than ever also essential growers research what their optimum CO2 levels are so they can target their approach more effectively,” she adds. Even reducing levels a small amount offers that ability to move some of their energy requirements away from grid and to renewables. “
CambridgeHOK is working with some growers staggering the energy profiles of different parts of the glasshouse so that they are divided into sections and receive different amounts of heat and CO2, for example, depending on the current growing stage of the crop. This more targeted approach to energy can lead to savings,” she says. “This approach especially for new-build can help reduce peak loads and in turn reduce grid connection costs and standing charges etc.
“We are also working with growers to help rethink the way they store their energy and at what time, so it can be released at a time of day that is most efficient,” she adds.
Most glasshouse growers do not have a massive amount of spare land for additional energy infrastructure, but certain changes can still be implemented inside the glasshouse, says Ms Penn. “In some cases solar panels can be added to the lower half of glasshouse walls, below the crop line, for example. Even insulated panels below the cropline can have significant energy savings. Investing a little more in the original structure can offer substantial benefits to the long term OPEX of the glasshouse.
“Despite the end of the RHI recently there is also evidence to suggest that investing in biomass still stacks up with some growers buying RHI accreditations and transferring it to a biomass boiler, that way covering the cost of the install.”
Ms Penn also thinks that more collaborative working between growers can help. “Energy as a shared system is an interesting approach where you have different glasshouse businesses working next to each other. Pooling together the energy inputs but still being able to manage them independently can lead to savings.”
Hydrogen is also becoming of interest. “Hydrogen has benefits for growers because it is cleaner and cheaper and you can still produce the CO2,” says Ms Penn. “I believe it will become widely used in horticulture in the future”.
“There are lots that can be done if growers can embrace energy modelling and invest a little more now to save for the future.”
Elsewhere, David Summerfield, Director at Bridge Greenhouses reports a strong interest in energy screens to increase savings. Working with suppliers Bridge uses screen cloths from Svensson, Phormium and Ridder, and the energy screens are one of the easiest and most cost-effective ways of making huge savings within a short space of time. Energy screens are a “closed” cloth with varying amounts of shade/clear strips depending on the requirements of the grower. The clear strips allow light through, but limit the flow of warm air through the screen, compared to an “open” shade screen which allows air to travel through the screen. With the energy screen in place growers can start to see significant energy savings, which can be further enhanced by installing vertical energy screens in the walls of the glasshouse.
“Growers can save 40% plus on heating costs by using energy screens and potentially even more by using a double screen, which gives the uncompromised benefits of both the shade and energy screen cloths. Blackout screens are often used as a second energy screen, which gives the benefit of preventing light pollution from grow lights, and also daylight control if required.
He says small savings can be made across existing glasshouses that could add up to larger savings over a year. “Switching from HPS to LED grow lights is definitely more efficient and the capital cost of LEDs have come right down while they are delivering a much better performance.”
Mr Summerfield also advises growers to take a closer look at their environmental control computer systems. He agrees that savings can be made here also. “Quite often once the optimum setting is realised it is installed and the environmental control system never gets adjusted by the growers other than to change the environmental conditions. But growers might find small things they can check such as whether the vents are being unnecessarily opened when the heat is on, or some pumps could be running 24 hours a day when they don’t need to. We highly recommend getting one of our controls experts to look over the system to make sure it is running as efficiently as possible. Equally, things like the amount of time grow lights are on compared to actual external light conditions, or maybe they could be dimmed at certain times are also important to consider. All this added together could make big savings over the year.”
Looking to the future, Mr Summerfield says that with the current energy crisis, and a push for carbon savings, renewables are definitely back on the agenda. “Interest in renewables took a dive after the removal of the RHI but has increased again after the rise in energy prices. Heat pumps can be ideal to consider if you don’t need CO2 and are particularly interesting if you are near a large water source (river, lake etc) and have a decent amount of electricity available on site.”
Bridge also supplies air, ground and water source heat pumps as well as biomass boilers and will advise growers on which is more suitable after an initial feasibility study.
NFU Energy’s Renewable Energy Solutions service can help growers by providing impartial advice and to put potential customers in touch with a network of trusted installation partners, coupled with finance and insurance options.