Energy Crops
Feasibility Study into the growth of energy crops
Background
In September 2012, the largest Dry Anaerobic Digestion (AD) plant in the UK was commissioned for Fife Council, with the Council taking over operational responsibility in March 2013.
The main feedstock for the plant is co-mingled household food and green waste, the latter of which is subject to significant seasonal variation. Whilst the Business Plan for the facility took this into account, the Council was keen to identify opportunities to boost green inputs in the autumn and winter seasons.
Consequently, the Council engaged OIS Ltd, working in partnership with the University of Strathclyde to undertake a feasibility study into the growth of Reed Canary Grass on restored sections of a landfill site to determine its potential as a cost effective feedstock for the AD Plant.
Growing trials carried out from April 2013 to October 2015 established that Reed Canary Grass could be grown effectively on suitably prepared brownfield land and at costs that were sustainable.
As a result of the success of this preliminary work, OIS was commissioned to draft a Business Plan for the use of brown field and closed landfill sites to produce energy crops as an AD feedstock on a larger scale.
OIS Ltd worked closely with Fife Council's Estate team to identify a number of sites that were within close proximity to the AD plant, of suitable size and readily accessible.
Expanding the Study
OIS Ltd identified 5 sites that were suitable, and proposed that the sites be prepared using non PAS 100 compliant green waste compost. As a result of the successful trial involving Reed Canary Grass this plant was chosen as the Energy Crop. Other factors influencing this choice included the fact that it is native to Scotland, resistant to the climate conditions faced in Scotland, it grows rapidly, and it resists the take up of contaminants in the soil.
Following instruction from the Council to develop the sites, Exemptions from the requirement ot apply for Waste Management Licences were registered with SEPA. Site preparation involved:
- Flailing the existing growth
- Applying glyphosate
- Disking the fields to break up the surface. Where the site was a partially capped former landfill site, it was agreed that the fields could not be disked or power harrowed to a depth greater than 300mm.
- Removal of boulders
- The application of 500 tonnes per hectare or less of non PAS 100 compliant green waste compost, depending on the individual waste exemption permit
- Disking the compost to incorporate
- Broad cast or drill seed the reed canary grass at a rate of 20kg per hectare
- Cambridge Roller to prevent the seed from blowing away or damage from wild life.
As a result of the success of this preliminary work, OIS was commissioned to draft a Business Plan for the use of brown field and closed landfill sites to produce energy crops as an AD feedstock on a larger scale.
OIS Ltd worked closely with Fife Council's Estate team to identify a number of sites that were within close proximity to the AD plant, of suitable size and readily accessible.