This past winter represented a considerable relief for growers of protected crops. Following last year’s withering energy prices, this season saw a return to normality which, while still far from ideal, at least allowed many of them to post some more reasonable numbers.
The constantly rising costs of recent years, however, have brought into greater focus than ever before the need for good quality heating and lighting technology, equipment that above all is capable of offering relatively quick payback in terms of energy cost reductions.
Colin Frampton of leading chrysanthemum grower Donaldsons believes that there is a huge amount of developments going on in terms of energy saving technology, both at home and abroad, with the key focus being on initial cost outlay and payback time.
The watchword nowadays, Frampton believes, is ‘control’. In terms of lighting, equipment such as electrical ballasts offer much more control, he believes, with 3-4 percent electricity savings possible - critical differences for growers of cucumbers, tomatoes and other crops. For heating it could be something such as converting boilers to variable speed boilers, though he adds the caveat that growers have to be careful of the high costs associated with conversion.
Insulation is an area where Frampton feels that growers could still do more. Valves, bends and control valves are all areas that could benefit from insulation, with significant amounts of heat lost from these.
Frampton and his brother Alan travel the world looking at the best glasshouse technology and growing techniques available, and Alan Frampton believes there is much that the UK growing industry - and indeed government - could learn from their overseas counterparts.
There is a great deal of work being done in the Netherlands on selling electricity back to the grid, with a staggering 20 percent of electricity in that country now supplied by the glasshouse industry, which virtually operates mini power stations in certain areas. Operators of CHP plants work co-operatively with local energy suppliers so that everybody benefits. In some instances growers would have lost money on pure crop production had it not been for the fact that they could sell energy back to the grid. “Everyone’s laughing in that system,” Alan Frampton says. “Why doesn’t our government do it? It makes so much sense. There’s a complete lack of co-operation here between generation boards and anyone with CHP.”
Co-operation, Alan Frampton believes, is the key to successful local energy supply, with larger groups of growers having more opportunity to obtain favourable contracts.
Both brothers stressed that the key to the relief that many growers have felt this winter has been a combination of lower energy prices with higher temperatures. This has had a massive impact on the amount of energy expended for protected production.
One firm that knows all about the pros and cons of combined heat and power is salad grower Buckland Garden Nurseries. Five years ago the firm signed a 15-year deal that would mean it benefited from both lower heating bills and more control over its carbon dioxide inputs.
The journey has not been all plain sailing though. Buckland’s Chris Harvey explained that last October the company that undertook the installation and managed the contract, which had been losing money all the time it was on it, came to him and presented him with a tough decision: release them from the contract or see the firm go under. Harvey chose the former option, whereafter Scottish Power stepped in to run the site, with the engine running from 7am to 11pm.
Though he has not seen a bill since Scottish Power took over, Harvey projects that considerable savings could be on the cards - up to 60 percent better than last year. “I think other growers would love the system,” Harvey maintains. “We have as much CO2 as we want and yields are ahead of last year as a result.”
Harvey says that the idea of introducing modern lighting installations has never really been an option for his company - Buckland is in an area of outstanding natural beauty and is not likely to be looked on too kindly by locals or the council if the nursery were to introduce lighting.
Fellow salad grower, Essex-based pepper specialist Valley Grown Nurseries, is another that has for some time been at the forefront when it comes to operating under glass with the most modern equipment. Nursery manager Gary Taylor points out that the firm is a fairly high end user of energy even within protected horticulture, with an annual energy bill coming in at a hefty £450,000.
Taylor explains that there are numerous ongoing trials with the HDC looking at ways in which glasshouse growers can become more energy efficient, involving, for instance, the retrofitting of boilers, lagging buffer tanks and the like. Such techniques saw the firm save 24 percent on its energy bill last year, with a further 21 percent expected to come off that figure this time around.
On the subject of developments abroad, Taylor says that there is a movement towards taller glasshouses in the Netherlands - up to 10 metres in some cases - which represents double the height of that at Valley Grown. “Taller glass eliminates the need to ventilate above the crop,” he explains. “You have as much air below the crop as above, giving a better climate. So people are looking at taller glasshouses, but how tall can you go? They are huge sheets of glass. But then how do you get to the thing? We don’t have 10 metre ladders, so the logistics of this need addressing.”
Taylor qualifies this by adding that in the old days some glasshouses had huge roofs, so it may be a case of going full circle rather than being entirely revolutionary.
There are also HDC trials going on in terms of supplementary lighting, a subject on which Taylor says growers are ‘still learning’. “It’s not as simple as just installing lights,” he insists. “You ideally want the high-wired layer system. But you need to shade the plant, and layer the crop. And for instance the bobbing system for layering means increased labour. The implications in terms of labour for cucumbers is one that needs addressing.” However he does add that when managed correctly artificial lighting can bring benefits in the shape of two to three times as many cucumbers.
So what will the glasshouse of the future look like? Taylor envisages movable benches, with artificial lighting, or some hybrid of that system. The Dutch, as ever, have already set themselves ambitious targets, with the aim of being entirely free of fossil fuel reliance by 2020.
Taylor admits that the UK lags behind the Dutch on such targets, but says that work is beginning on looking at the use of bioethanol and biobutanol. He also proposes that one solution might be some form of partnership between the agricultural and horticultural sectors that would see more of a mutual collaboration in terms of production and usage of these.
One reason the Dutch can - and do - put such attention into developing glasshouse technology might be explained by the sheer size of their industry. While the UK might produce 150ha of tomatoes and 85ha of peppers, the Dutch grow 1,280ha of each. On the plus side, the Dutch consequently suffer from overproduction while there is still opportunity and a better supply-demand ratio in this country.
Ironically, all the measures that Valley Grown Salads has put into place over the last few years has not saved its annual energy bill from rising fivefold to around half a million pounds; looked at in reality though, the 65% reduction in energy used has in all probability kept the company in business.
Chris White-Moncrieff, operations director at Humber VHB, believes that the most important thing about glasshouse lighting systems is the reliability. Some systems work well while others do not. On thermal screen, the jury is still out: “Lots of us put movable screens in for heat saving, but many growers also put in a fixed screen and said that it led to loss of light. With tomatoes we felt you couldn’t afford that loss of light.”
White-Moncrieff says that conditions this winter were much easier than the previous year, with energy costs dramatically lower. This has led to a greater mood of optimism within the industry.
This optimism can be tangibly noted in the number of high profile glass installations that are coming on stream this year. Flavourfresh Salads last week openend a new block of glass that will be used to grow produce for Marks & Spencer, while earlier this year the first year-round tomatoes to come out of John Baarda’s impressive and energy-efficient Billingham site began their journey to Sainsbury’s.
But for manufacturers, there is clearly plenty to work on. Priva’s Mike Powell notes that there is more of a trend towards CO2 enrichment to aid the growth of plants. He detects that climate change is having a perceptible impact in the sense that a warmer climate is seeing less use of heaters. On the contrary, he says that there are more cooling and misting systems being put into place, a trend that he envisages becoming stronger in future years. l
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