Solar energy helps dairy unit boost productivity

Roof-top installation reduces energy costs for Norfolk farm

A Norfolk dairy unit is reaping the rewards after installing a solar energy system to reduce its electricity bill.

The Airfield Herd of pedigree Holsteins comprises 600 dairy cows plus followers and 300 beef calves reared out of the dairy herd. It is part of Grange Farm – an 800ha mixed arable holding at Shipdham, five miles south-west of Dereham.

Rob Proctor, who looks after the dairy herd, farms alongside his brother Ralph, who looks after the arable side of the business. The brothers farm in partnership with both their parents, Ken and Rebecca.

“We’re a mixed farm and our goal is to maintain that balance of livestock and arable – the dairy herd producing organic fertiliser for the crops and the crops producing feed and bedding for the livestock,” says Rob.

Bottom line 

Each side of the business supports the other – but each must also be profitable in its own right. “Whether it is straw or muck coming in or out, the symbiotic relationship is really important to us – but so too is the bottom line.”

Dairy diets are maize-based, with 250ha of the crop grown annually. There are also 100ha of lucerne, 50ha of temporary grass and 50ha of permanent grazing. The remainder is an arable rotation of wheat, barley and oilseed rape.

Combinable crops are grown for premium markets where possible. Milling wheat goes to Warburtons and oilseed rape goes to Croda Agriculture – where it is used as a simple but effective alternative lubricant to mineral oil.

“We like to invest in our crops where it makes sense to spend a little bit more,” says Rob. “It’s the same with our maize and lucerne crops. We will spend a more on a seed variety so we get a better energy yield.”

Having maize in the rotation also helps control blackgrass – particularly useful when cleaning up new parcels of land which have been brought into the business.

Maize is established by a Sly strip drill; cereal crops are established using a Claydon. Tractors are mainly Claas from Manns of Saxham, as is the combine harvester.

Monitoring progress

Cows are milked three times a day producing 12,800 litres per cow year – about 940kg of fat and protein per lactation – for farmer-owned cooperative Arla and a Morrisons-aligned contract.

“We’re working closely with Arla and Morrisons in terms of their producer schemes – constantly striving to become more efficient and monitoring our greenhouse gas emissions for more than a decade now.”

The farm is committed to reducing its carbon footprint, adds Rob. This means producing high quality milk in a sustainable way while minimising emissions and constantly exploring better ways of working.

“We do an annual carbon audit on the farm and it gives us a score so we know where we are each year in terms of emissions. There’s a further incentive on our milk price as well to reduce our electricity usage.”

Climate rewards

Dairy farmers who undertake climate-friendly actions are rewarded under Arla’s climate check scheme. These actions include reducing artificial nitrogen fertiliser usage, increasing feed efficiency and using renewable energy.

“We are 18 months into the scheme,” says Rob. “But we’ve been doing things like cover cropping for more than 10 years. Right now, we’re installing a slurry system which will separate liquid and digestate into more manageable products.”

The new slurry system will give the farm more control whether it spreads waste as a fibrous product or an organic liquid – benefiting growing crops in the spring. It will take bedding sand out of the mix so it can be cleaned and reused more efficiently.

But one of the most significant investments has been the installation of a 214kw solar photovoltaic (PV) array on the roof of one of the sheds.

It has dramatically reduced the farm’s electricity consumption – both during and after milking.

Energy demand

“We use a lot of electricity and the solar PV system really suits our business. We sell 20,000 litres of milk every day and all of it has to be cooled immediately – so we have a huge demand for energy.

“The idea was to use our ice banks as a battery so we could cool the milk using renewable energy. That was really the driver to installing the solar panels and the fact we use lots of electricity during the day means it really stacks up.”

The installation is by solar energy experts Impact Services. “They produced a report for us that laid everything out in simple terms and we could see exactly how it was going to be and what the project would involve,” says Rob.

The system was sized specifically to the farm’s requirements – not just in terms of the roof size but in terms of the amount of electricity it needed to generate. “It was really important to us for it to be done correctly – that it wasn’t too big or too small.”

Installation took place over a number of weeks and the solar panels started generating electricity last year. “Now when we’re milking the electricity meter isn’t moving – we’re much more in control of our own energy.”

Confidence

With electricity costs on the rise, it was just what was needed. “We were kept involved all the way through and I’ve every confidence in the quality of the work too – you hear some horror stories about people installing solar and it not being done correctly.

“I couldn’t fault the installation. Nothing was damaged and there was no mess afterwards. They’ve done a really good job. It hasn’t been fully operational that long but it’s already made a positive difference.

“I can stand there while the team are milking the cows and the electricity meter won’t be moving around at all – which is a good feeling. It was a big job for us but the way we’ve been hand-held through the project has been a really good experience.”

The plan now is to feed any surplus electricity back into the grid. This meant a new connection was required – which Impact Services has taken care of – and it will be up and running early this year.

“We’re really happy,” says Rob. “They are a good company and friendly too. What’s more, they’ve delivered exactly what we wanted – we would definitely recommend them to other farmers too.”