Renewable diversity helps Scots farm build greener future

When Iver Salvesen and his family bought the 240ha Muirhouse Farm near Stow, Galashiels, in 2003 it soon became clear they had to diversify income to protect the long-term viability of the predominantly sheep grazing farm.

A planned extension to the farmhouse provided the impetus to examine energy use and ways of reducing fuel costs in more detail. “We began by measuring energy use across the farm, including the house, and discovered we were consistently using around 5kW of electricity,” says Mr Salvesen.

With an average wind speed of 5.5m/s across the farm, up to 7.8m/s and 11m/s on more exposed sites, wind turbines were the obvious technology to suit their needs, he says.

See also: Weigh up the renewables options for your farm

“The effective output of wind turbines is around one-third of quoted capacity, so we decided to apply for planning permission for three 5kW turbines to ensure we could mitigate our own power use as much as possible.”

Opting for smaller turbines meant obtaining planning permission was relatively straightforward and grid connection could also be done under a G59 exemption into the existing supply, therefore keeping costs down.

But funding was less easy, as the project coincided with an economic crash and increasing nervousness among banks to lend.

“In the end we went with what we could afford ourselves, which was a 2.5kW Skystream turbine. We did a lot of the groundwork ourselves to keep costs down.”

A range of technologies

At the time the first wind project was being developed, Mr Salvesen also changed the oil-fired Aga to an electrical one and installed a 16kW ground-source heat pump to heat the new extension.

Trench digging for this system was done in-house to reduce costs and the system was fitted in 2009, unfortunately just outside the July cut-off to qualify for approval under the Microgeneration Certification Scheme (MCS). This means the system does not qualify for support through the Renewable Heat Incentive. 

“As we got more involved with renewables, I wanted to better understand the sector, so did a part-time degree at the Centre for Alternative Technologies in Wales.”

From then on, there has been a drive towards renewables across the farm and there are plans for more. Mr Salvesen has also started his own renewables company (eco2fitter).

Two 5kW wind turbines and 4kW of rooftop solar have been installed to supply electricity to the farmhouse, offices, two holiday lets and a mobile home for the farmworker.

A 200kW woodchip biomass boiler supplies heat via a district heating network to the farmhouse, office, one holiday cottage and a new eco-home constructed of straw bales – the farm has planning permission for five more straw houses. Some heat is also used to dry 30-35t of home-produced woodchip in a converted farm building. A 65kW wood pellet boiler has also been installed.

Mr Salvesen says the technologies complement each other well in terms of their generation profiles through the year, making the business as “self-sustaining” as possible. For example, wind turbines generally produce more energy in the winter when there is less from the solar, while the opposite is true during the summer.

Lessons learned

While most installations have been reasonably straightforward, the process has not been without its issues, says Mr Salvesen.

For example, positioning the wind turbines close to the farm reduced the need for expensive cabling but meant they were not in the area with the best wind speeds. He is now looking to install two larger turbines (100kW each) in a windier position but the planning process is proving more complicated.

“There are economies of scale with wind turbines and biomass boilers, so it’s worth going for as big a system as you can afford from the outset, rather than trying to increase capacity further down the line.”

There were also some “teething problems” with the grid connection for the solar panels. The farm is at the end of the grid supply and suffered fluctuations in voltage beyond the 5% margin allowed under the MCS, he says. “We eventually managed to get the power company out to check the grid and sort the issue out.”

The biomass boiler and piping for the heating network also proved expensive to set up, however connecting it to as many properties as possible will significantly improve payback, he says. The biggest issue with woodchip boilers is consistency of fuel supply and ensuring it is at the optimum moisture content, he says.

Muirhouse Farm renewable energy installations

4kW solar (Sheuco & SMA)

Independent renewable energy advice for Scottish farms

Mr Salvesen’s farm is one of those that has hosted visits as part of NFU Scotland’s three-year Renewables Development Initiative (RDI).

Through a programme of on-farm events, co-ordinated by Smiths Gore, the RDI aims to provide independent renewable energy advice to Scottish farmers and land managers.