Stewart Tower Dairy installed a wind turbine for dairy farm operations to tackle rising electricity costs and gain greater control over its long-term energy expenditure. The NPS 100-21 now generates approximately 160,000 kWh of renewable electricity per year, supporting the farm’s dairy and award-winning gelato production.
Located in Stanley, Perthshire, Scotland, the project demonstrates how on-site wind energy can help an energy-intensive agricultural business reduce electricity costs while creating an additional source of income.
The Challenge: Rising Energy Costs for a Dairy Farm
Stewart Tower Dairy produces high-quality milk used to make a range of award-winning Italian-style gelato. Running the dairy, farm shop and café requires significant amounts of electricity, making rising energy prices an important operational challenge.
In 2010, Stewart Tower Dairy was paying more than £1,300 per month for electricity. By the end of 2012, monthly electricity bills had increased to approximately £2,000.
Owner Neil Butler began investigating renewable energy options and identified wind energy for agriculture as a way to gain greater control over the farm’s energy costs.
The objective was clear: find a robust and reliable renewable energy system capable of producing significant amounts of electricity while keeping maintenance requirements under control.
The Solution: A 100 kW Wind Turbine for Dairy Farm Operations
After evaluating the available options, Stewart Tower Dairy selected the NPS 100-21, a 100 kW wind turbine installed on a 37-metre tower.
One of the main reasons behind the decision was the turbine’s Permanent Magnetic Direct Drive (PMDD) technology. Unlike conventional geared wind turbines, the NPS 100 uses a gearless direct-drive architecture.
With an engineering background, Neil Butler recognised the potential maintenance advantages of eliminating the gearbox. A nearby geared turbine reportedly required servicing approximately every 800 hours, while the NPS 100 was serviced once a year.
The NPS 100-21 was also selected for its ability to deliver high annual energy production and take advantage of the UK’s Feed-in Tariff programme in place at the time.
“The NPS 100 has a very good reputation as a tried and tested product.”
— Neil Butler, Owner, Stewart Tower Dairy
Farm Wind Turbine Configuration
The Stewart Tower Dairy project included:
| Location | Stanley, Perthshire, Scotland |
| Application | dairy farm, ice cream production, farm shop and café |
| Wind turbine | NPS 100-21 |
| Rated power | 100 kW |
| Tower height | 37 metres |
| Average wind speed | 5.6 m/s |
| Annual Energy Production | approximately 160,000 kWh |
| Annual carbon offset | 120 tonnes, as reported in the original project case study |
| Original incentive | UK Feed-in Tariff |
The turbine was ordered in July 2012 following financing and planning approval and began generating electricity in January 2013.
Results: 160,000 kWh of Renewable Energy per Year
The farm wind turbine delivered immediate economic benefits. According to the project’s 2013 operating figures, the NPS 100-21 generated approximately 160,000 kWh of electricity.
The original project analysis recorded:
- £33,600 in Feed-in Tariff income;
- £4,750 from exported electricity;
- £7,800 in electricity savings;
- £30,550 in total additional income;
- £38,350 in combined annual income and electricity savings.
The project was expected to generate approximately 60% of the farm’s electricity requirements, helping protect Stewart Tower Dairy from volatile and increasing energy prices.
From Energy Costs to Long-Term Business Value
The benefits went beyond electricity generation.
By producing renewable electricity on site, Stewart Tower Dairy was able to turn energy from a growing operating expense into an asset supporting the wider business.
For an agricultural operation combining dairy production, gelato manufacturing, a farm shop and a café, greater control over electricity expenditure provided an important long-term advantage.
The project also created a marketing opportunity for the business. Stewart Tower Dairy could highlight that its gelato was produced using milk from its own farm while generating its own “Green” electricity.
This combination of energy production, cost control and sustainability demonstrates the wider potential of a wind turbine for dairy farm and agricultural applications.
Why Direct-Drive Wind Technology Matters for Agriculture
Agricultural businesses need energy systems that can operate reliably without creating unnecessary maintenance requirements.
The NPS direct-drive architecture eliminates the conventional gearbox, reducing the number of mechanical components associated with traditional wind turbine drivetrains.
For Stewart Tower Dairy, this was an important consideration when selecting a turbine designed to operate alongside the farm’s core activities without requiring constant attention.
The project demonstrates how wind energy for agriculture can support businesses seeking to combine on-site renewable generation, long-term energy cost management and operational reliability.
Looking for a Wind Turbine for Your Farm?
Northern Power Systems provides wind energy solutions for agricultural, commercial and industrial applications.
If you are evaluating whether a 100 kW wind turbine could support your farm or agricultural business, our team can assess your site, energy requirements and potential project configuration.
Contact Northern Power Systems to discuss your wind energy project.