Project: Strathaven Airfield
Technology: solar PV and battery storage
Location: Strathaven, South Lanarkshire
CARES funding: £10,570 capital funding. Match funding from South Lanarkshire Council Renewable Energy Fund and own funds.
Date installed/operational: March 2021
Strathaven Airfield is Scotland’s oldest continually used airstrip and the third oldest operational airfield on the west of Scotland mainland. It was founded by The Scottish Flying Club in the early 1960s after it moved from its former base at Glasgow’s Renfrew Airport. On 30 June 2015, airfield operations were transferred into a new not-for-profit company limited by guarantee, Strathaven Airfield Ltd.
Strathaven Airfield is a traditional airfield with grass runways, taxiways and parking areas. Within the airfield site there is a clubhouse, two hangers, several small buildings and 32 aircraft. The clubhouse, which is approximately 10m x 10m in size, is used on a daily basis and electricity demand is usually during the day.
Strathaven Airfield aims to become self-sustainable. To reduce its energy consumption and become more efficient and environmentally pro-active, its buildings are all fitted with LED lighting, and it has an electric vehicle charging point on site too. The airfield also uses electric mowers which use fast charge during the day and slow charge overnight.
Strathaven Airfield identified that its electricity demand had been increasing as it moved from using from fossil fuel-powered to electric equipment and more members and visitors were using electric cars and bikes to access the airfield. It has also seen a small increase in demand from new technologies that assist safer and more efficient flying.
To gain a better understanding of its energy demand and the possibilities for generating its own electricity, Strathaven Airfield contacted Zero Waste Scotland’s Energy Efficiency Business Support Service (EEBS) for advice. An advisor carried out a detailed energy efficiency assessment and advised the company that it could benefit from installing the following technologies:
- an air source heat pump at the clubhouse
- solar photovoltaic (PV) panels and battery storage
- robotic lawn mowers to replace diesel, sit-on mowers.
The report estimated that the benefit of implementing these recommendations was savings of £4,241 each year, with an overall pay back of 11.7 years, based on an estimated capital expenditure of £49,829. The changes would also result in carbon savings of 8.8 tonnes.
When considering its renewable energy options, it was initially thought that there may be limited opportunities because the airfield has a single-phase supply. It also noted that generating electricity by wind would be difficult because of wake vortex turbulence; solar panels were considered more appropriate because of the site’s open aspect and they would match well with the airfield’s energy demand. The non-profit company operates in daylight hours and there are no flights at night or in times of low visibility.
Project aims and objectives
Strathaven Airfield wanted to go further than using green energy tariffs and take advantage of its exposed position to generate its own electricity on site. The report from EEBS had already identified that the company could benefit from installing solar PV panels and battery storage. By installing battery storage alongside solar panels, it could maximise the use of any energy generated by storing excess electricity for use on demand, thereby reducing both the company’s costs and environmental impact.
As a not-for-profit, Strathaven Airfield supports community involvement; a major aim of the project was to engage local people in renewable energy systems, hopefully encouraging the development of further systems in the local and surrounding areas. As well as being an exemplar for local residents and businesses it also wanted to show other small airfields in the UK that there are modern, efficient and environmentally beneficial ways of operating. Strathaven Airfield was unaware of any other recreational airfield attempting to make ground-based operations zero-carbon in the near future. It also wanted to demonstrate to others that solar panels can be a viable solution even after the closure of subsidies such as the Feed-in Tariff.
Outcomes and achievements
In 2020, Strathaven Airfield applied for funding from the Scottish Government’s Community and Renewable Energy Scheme (CARES). It was awarded CARES capital funding of 60% towards the total cost of the 10kWp solar PV installation and 50% towards the 13.2kWp battery storage installation.
The company also successfully applied to South Lanarkshire Council’s Renewable Energy Fund for Banks Renewables Wind Farm grant funding (Middle Muir Windfarm) for match funds.
The project was managed and delivered by Colin MacKinnon, the airfield secretary. As well as financial support, Mr MacKinnon received free and impartial support from a Local Energy Scotland development officer for procurement. He used the CARES solar PV framework of contractors and the Microgeneration Certification Scheme (MCS) register to request quotes from three potential installers, who carried out site visits.
After following a robust evaluation process, the airfield appointed Procast, a local installer, to deliver a turn-key service for the solar PV installation. Procast offered value for money by providing additional support with gaining permission requirements, such as providing sample PV panels for glint and glare surveys.
The site visits led the airfield to amend its proposal in order to reduce installation costs and improve fiscal efficiency, thus reducing payback period. Initially a ground mounted system was proposed but following further assessments it was decided that a roof-mounted system on the hangar building would be preferable. The size of the installation was also limited due to the site having a single-phase supply. EEBS’ report had calculated projected consumptions and suggested installing a 10kWh array and a 14kWh battery. Installers initially suggested a smaller battery would be more appropriate, but after detailed modelling of the airfield site’s energy demand, it was decided that a 13.2kWh battery would be suitable.
Local Energy Scotland supported the airfield to get the required permissions for the project. As the solar PV installation was small-scale, a grid connection was avoided and the airfield was able to use a G98 option for grid connection (connect and notify) with Scottish Power Energy Networks, the local district network operator.
The project required planning permission because the installation is on an airfield. The process involved carrying out various surveys such as glint and glare assessments. A structural engineer’s report and building warrant were also required for the hangar building to ensure that the roof structure was adequate for solar panels. Procast provided all plans and specifications to the airfield to support its planning applications to South Lanarkshire Council.
The solar PV installation was completed in March 2021. The panels are estimated to generate around 15,3072 kWh over 25 years and offset around 8,766 kWh annually. Carbon savings are estimated at 44,812kg for the system over twenty years. When the site is producing more electricity than is required, the system trickle-charges the battery storage system. With clever load-balancing, the stored power can be appropriately distributed to allow the airfield to move towards self-consumption as much as possible.
Strathaven Airfield has developed a maintenance schedule for its new system and its insurance policy was amended to adequately insure the batteries and solar PV panels. It also installed a smart meter to help identify the source and the time that the energy is used. The airfield publishes its monitoring data on its website to generate ideas from its members on more efficient ways it can use its power and to inspire others to install renewable energy generation.
“The energy savings are simply fantastic.”
Colin MacKinnon, Strathaven Airfield
Colin MacKinnon, Secretary of Strathaven Airfield, said:
“Key to the successful on-time completion of our project was using the various skills of club members. For example, one of our members had been a senior procurement manager for an Ayrshire Council and so was able to draw up a decision matrix. Without his input and the support received from Local Energy Scotland, we may not have selected such a suitable contractor. Our advice: never stop asking questions!
“The biggest surprise is the interest we received from members of the public. Solar PV and battery storage are established technologies, and many will have seen it on their neighbours’ houses. But perhaps they are shy at asking their neighbours questions? We discuss everything – and we publish our finances, so we get asked lots of questions!
“The energy savings are simply fantastic – the graphics from our supplier Eon tell the story! The next stage will be to show how much we are exporting too.”
The success of the project has certainly raised awareness of renewable energy and energy efficiency amongst its members. Colin explains: “People are now just much more aware of energy use – one club member waited until the kettle had boiled before turning on the microwave because he didn’t want to seek more power than the panels were generating! And, prompted by our project, another club member has bought an all-electric MG car. We have had excellent local publicity. Our next steps are to get articles in flying magazines.”
As with many other local energy projects, the airfield had to contend with difficulties caused by COVID-19 restrictions and lockdowns. Colin said: “Covid created a lot of stress in meeting deadlines, but it has possibly been a benefit – people are desperate for things to do outdoors, so we are getting many more families coming to the airfield to watch the aircraft. Our robot mower is a big hit with all ages, and it gives a chance to explain about our solar PV and battery project.”
What are the airfield’s next steps? Colin says “We have our second electric robot mower on its way as we work to end fossil-fuel powered grass cutting.” He adds: “We also want to install information display panels. And more ambition! Members are already looking at the first all-electric aircraft to be approved for European flight and want to be the first airfield to achieve net-zero.”