Green is the goal

Sustainability is sexy. Self-sufficiency, being eco-friendly or going 'green' is as in vogue in relation to plant design as it is when it comes to food miles and packaging. But if you thought it was just about installing wind turbines and solar panels, think again. There are more routes to sustainability than there are varieties of confectionery in a tuck shop.

Incentives for making factories more eco-friendly keep multiplying. "We recently came across the Welsh Development Agency looking for factories to meet the requirements of the Building Research Establishment's Environmental Assessment Method before granting funding for construction projects," says Geoff Daren, commercial director at MTC Insulation Solutions.

One source says local authority planning regulations are increasingly requiring construction projects to have sustainable features. "A certain percentage of a building's energy requirements has to be shown to be met by renewable energy sources," said the source.

The approach stems from the Merton Rule, pioneered by the London Borough of Merton in 2006, based on government Planning policy statement 22 (PPS22): planning guidance on renewable energy. Merton required 10% of all energy from new developments to come from renewable sources. Other councils have since set higher targets.

Sustainable plant design therefore seems less like a choice and more like an imperative than ever before. The dilemmas lie in how that goal is realised. Like everything else in life, there's no 'one size fits all' solution. But some ideas are more popular than others and for the financially savvy, there are ways of recouping outlay in a sensible timescale.

"Many solutions give you a return on investment (ROI) in 10, 15, 20 years, whereas the solutions that give a return in two or three years are very different," says one major contractor.

Tim Elsome, md of Elsome Engineering, says: "It used to be two or three years. Now people are looking for ROI in 12 months."

That said, some are beginning to take a longer-term view. "One global drinks company sets aside tens of millions of dollars every year for sustainable projects," says Steve Turner, engineering director with responsibility for sustainability at Lorien. "It's happy to accept a 25-year return on a biogas boiler and up to 40 years on buildings and infrastructure."

However, he accepts that this is unusual and would only work for certain companies. "It's very visionary. If you want to do sustainable projects, if you're not going to get immediate payback, they have to be led from the top."

Biomass and waste

Two popular areas of exploration for processors are water use and biomass boilers. "Using biomass and waste product from its factories as a source of energy is a definite consideration for one major client," says Daren, adding that it's a popular choice for meat processors. Contrary to some people's perceptions, biomass boilers do not occupy a huge amount of space, he says.

Turner says: "We're working with a number of organisations that have been involved with biomass and integrated waste projects. Everybody seems to be saying they want combined heat and power systems." But he adds a warning: "When they find out the cost, they are saying they thought it would be cheaper." Laverstoke Park organic farm is currently considering a biomass power proposal from MTC. Those who don't want to go that far can draw on existing biomass energy plants, rather than integrating a biomass boiler from scratch, he says.

Elsome cites further possibilities. "We're pushing energy efficient steam systems and getting involved with insulation for pipework and boiler systems. One client recovers condensate water and pumps it back into the boiler, so there's little latent heat loss."

Also popular, he says, is "conditioning gas at output by delivering a 12V charge around the gas pipe". This makes the gas molecules in conventional gas boilers burn at higher temperatures, producing more energy. "Payback time can be from 12 to 24 months and a boiler can run 4-10% more efficiently."

Plans that hold water

Robert Wiseman & Sons has been leading the way in terms of sustainable water use at its latest development, the massive milk processing plant at Bridgwater, Somerset. It has an on-site water treatment plant, which cleans used water to bathing standard, then recycles it for internal and external vehicle washing and irrigating a nearby cricket pitch. Production manager Julie Walker claims the company's three main plants can use just 0.5l of water to process one litre of milk, whereas most plants use 1.5l.

A less ambitious way to help conserve water is to install mains leak detection systems or sustainable, vertical drainage systems, so less water is lost to run-off, says Turner. Use of rainwater, possibly for bathroom facilities, is another option that Bridgwater also employs.

Aside from conserving water, one of the simplest and best sustainable features is good insulation. "The best ROI is from air-tight insulation," says Turner, who is speaking on ROI for sustainable projects at the Low Carbon Best Practice Exchange event on October 22 at Harrogate International Centre (visit http://www.carbon-innovation.com/harrogate). Daren says: "We use polyisocyanurate (PIR) panels, which are considered reasonably non-combustible, or [mineral fibre] panels where particularly strong fire resistance is needed. Up to 80% of insulated panels are PIR now, which are lightweight and fairly versatile."

Kingspan Group specialises in insulation methods using PIR, including what it calls controlled environments - or combined insulated wall and ceiling panel systems. Its KS1100 CS panels can be used at internal temperatures as low as -40°C and external temperatures of between 40°C and -16°C. The panels are extremely airtight, significantly slashing energy use and running costs.

PIR is industry standard, with the possible addition of foil back insulation, which reflects heat back to the panels. "With aluminium foil arguably you can get away with insulation being thinner," says Turner.

Robert Wiseman took the tack of making the wall insulation slightly thicker for Bridgwater. It considered 70mm, but eventually went with 80mm cladding, which was needed in some areas anyway, and traps marginally more heat. Of course, insulation can also stop heat from penetrating cold storage areas.

Insulation considerations can be extended to automated door design and accessories. Some firms use door alarms that trip when they are left open for long periods. "That encourages people to keep doors closed, limiting energy loss and ingress," says Daren. Union Industries sells a range of automated doors under its Matadoor brand, which work by sensor only when needed, minimising the energy required for temperature control.

Talking turbines

Once you've explored all the ways to reduce energy consumption, there's also the option of generating your own power. There's a lot of potential here, but it's an area that demands a lot of thought. "Solar energy would be in a wish list of people's food factory design ideals, but it always comes down to cost, which is hugely prohibitive so far," says Daren.

Wind turbines can be used at some locations, but not others. Bernard Matthews has secured turbines at plants in Pickenham, Weston and Holton in Norfolk and McCain Foods is installing three 80m high turbines at its Peterborough plant. But for every one of these ventures, there are more instances where turbines just aren't practical. Robert Wiseman says it considered them for Bridgwater, but was told that there was insufficient wind speed at the site to make them worthwhile. Then there may be objections from local residents if they are constructed near built-up areas. "Very often, it depends on the location," says Daren. "A lot of factories we build are in urban environments, where turbines don't tend to be as common as rural settings."

Talk of benefiting from turbines may just be hot air for some people. But everyone can benefit from considering how sustainable building materials themselves could be, says Turner. "Are the bricks used produced locally? From a report we did, responsibly sourced timber from renewable forests, and recycled aggregates, such as tarmac, are options." Wiseman's Bridgwater plant made use of wood from renewable sources in its construction.

There's clearly a lot to think about when it comes to sustainable plant design, but for those who persevere, there's enough financial benefit to make it worthwhile. And there are simpler options to consider, such as insulation and locally sourced materials, for those that don't have a lot of cash to splash. FM

''KEY ContactsElsome Engineering 01664 813234 Kingspan Group 00 353 429698000Lorien Engineering 01543 444244MTC Insulation Solutions 0845 2300082Robert Wiseman Dairies 01355 244261Union Industries 0113 244 8393''