How might climate change affect Stewart Tower?
Its predicted that Scotland will see warmer, wetter winters and hotter, drier summers, with more ‘extremes’ in our weather patterns. There has definitely been more unpredictability in the weather of late, for example the wet and cold start to 2013. This variability may impact on routine farming practices, meaning we need to look at all aspects of the farm business and make sure we are being as cost effective and efficient as possible. One of the aspects we have looked at is renewable energy. Installing the wind turbine has reduced our use of electricity produced by fossil fuels, enabled us to put energy back into the grid and contributed to a reduction in the farm carbon footprint.
Making best use of electricity
Before we looked at renewables, an energy audit was carried out on the farm. This was a useful activity, as it identified how we could reduce energy consumption on site, allowing us to make best use of both energy from the grid and renewable energy supplied by the wind turbine.
Options for renewables at Stewart Tower
Our scope for renewables on the farm was limited, with no watercourses that would support a micro-hydro installation and the position of roofs around the steading didn’t lend themselves to the installation of PV panels. Wind energy was deemed to be the best option. There were only a few sites suitable on the farm with a required wind speed of 7 m/s. The best site for the turbine was close to the steading and road, making it ideal in terms of construction access and transfer of electricity from the turbine to the site supply point at the farm steading.
Planning permission
Our biggest hurdle was getting the required planning permission; it took over two years to get the go-ahead to install the turbine from the Local Council. This could be in part due to the size of the turbine, as at 100kW it falls between the smaller systems and those used on the more commercial wind farms.
Site selection; points to consider
There were some key points to consider when thinking about possible sites for the wind turbine on the farm:
- Wind speed – was there enough wind speed at the site to make the project viable?
- Planning – What local and national planning restrictions existed at the site?
- Grid connection – could we get a grid connection point and how much would this cost?
- Access requirements – could delivery vehicles reach the intended site?
- Neighbours – was the intended location of the turbine going to cause issues for others?
- Electromagnetic interference – could the chosen location affect air traffic or radar installations?
Choosing the turbine
We investigated a number of manufacturers and suppliers to see what would be the best fit for our site.
We wanted to make sure that the turbine would supply a reasonable percentage of our daily electricity requirements and could operate in a range of wind conditions, maximising potential output. We looked at our annual electricity consumption and broke this down into daily use. We estimated how much daily output we could reasonably expect from the turbine and then looked at what size machine we would need to match our energy needs.
Reliability and on-going support was also a key consideration. The model we chose uses a gearless direct drive design, meaning there should be less to go wrong and makes for quieter operation. The turbine is also linked to the internet, allowing outputs and daily performance to be monitored plus real-time diagnostic support from the turbine manufactures if needed.
Operation and financial benefits
Energy used in the dairy, ice cream production and farm shop accounted for around 130,000 kWh per year. Calculations suggested that on an average year, the wind turbine would produce over 200,000kWh.
We estimate we would use half of this, potentially giving us a saving of around £12,000 per year on the electricity bill at 2013 prices. With the energy we sell back to the grid, plus the feed in tariff, the turbine could generate around £50,000 per year. We estimate that payback should be achieved within around 8 years. By generating energy from wind rather than fossil fuels, the turbine could offset in the region of 120 tonnes of carbon annually, equivalent to taking around 24 cars off the road per year.
Neil and Linsey made some key changes over the period of the project in addition to hosting events for visitors to Stewart Tower. With help from facilitator Sinclair Simpson, Neil and Linsey were able to reassess some routine practices which saved them around £10,000 per year. Steps included:
- Improving their fertiliser and dung policy
- Improving grassland management
- Tailoring fungicide sprays to arable crops
- Choosing disease resistant crop varieties
- Better use of electricity
- Installation of a 100kW wind turbine
Neil said: “We were already focusing on some of the areas that have been brought up in the project, for example we have a carbon footprint as part of our milk contract with Sainsbury’s. The initiative helped us to build on this and look at other areas where we could make a change. For example using less fertiliser and increasing clover in grass has had a benefit and is something that everyone can consider and adapt depending on their individual circumstances. One of the things that comes out of these projects is that the cumulative benefits add up, not only for the individual farm but if all farmers were to take up similar measures, could show a significant reduction in the carbon footprint for agriculture across Scotland.”
Farm Facilitator Sinclair Simpson said: “You need a proper understanding of what’s going on on your farm, and how best to work with what you have, so planning ahead to minimise potential losses from uncharacteristic weather as a result of climate change is important. Efficient farming systems have less impact on the environment, are better for business and can help us work towards our greenhouse gas reduction targets”.
