March 1, 2015 - March 1, 2016

Biomass Renfrewshire Feasibility Study

Locations:
Renfrewshire
Types:
Green Network Businesses, Woodland Creation
Funds:
CSGN Development Fund
Lead Partners:
Renfrewshire Council

Context

The Biomass Renfrewshire Feasibility Study aimed to discover how Renfrewshire Council’s existing woodland resource could be enhanced and used responsibly to create sustainably cultivated woodland for biomass fuel. The study aimed to discover if Renfrew’s 52 existing woodland sites (350ha) were suitable for growing sustainable wood to fuel woodchip heating systems. The scope of the study was extended to include 21 vacant, derelict and underused land holdings (145ha). The study also aimed to communicate with the public to gauge opinion on potential new sites and build potential partnerships with other members of the biomass supply chain.

Project background

Renfrewshire Council is committed to meeting a carbon reduction target of 25%. As a result, it intends to intensify its carbon management plan by switching to biomass boilers in its larger properties like secondary schools.

A previous study in 2015 identified 57 potential biomass using sites amongst Renfrewshire Council’s civic buildings and recommended initially progressing with five sites which would create a 1,000 tonnes demand for woodchip. Demand for a further 4-5,000 tonnes is readily identifiable amongst locations such as schools and recreation centres.

Demand for woody biomass is also steadily increasing across new developments in Scotland, such as the one at Paisley’s Royal Alexandra Hospital. These are increasing competition and raising prices. The cost of using biomass fuel in council property would be reduced by using locally and sustainably cultivated wood from Renfrewshire Council’s existing woodland resource and converted vacant and derelict land.

How the project was delivered

A study of existing woodland was carried out by RTS Woodland, Crieff. In order to establish the productive potential from the existing woodlands each was inspected and the growing trees evaluated – including an assessment of the existing timber volume. The management constraints were considered and recorded – taking into account guidance from Renfrewshire Council and from a previous woodland audit in 2011. The recommendations and constraints were applied to the woodland together with consideration of the UK Forestry Standards (UKFS) and Scottish Forest Strategy to establish what proportion of the woodland could be managed for biomass.

In order to consider what approach might be taken to woodland creation and biomass production on the vacant and derelict land sites, each was visited and the constraints were considered. These were initially subscribed to one of four categories – largely based on location and situation:

  • Category A were relatively unconstrained and a normal approach to woodland creation could be taken with a diversity of species and structure.
  • Category B had constraints relating to their urban location. These locations would be planted at a high density and managed on a short rotation (10-15 years) and be of a uniform crop.
  • Category C sites were exclusively urban and often park/grassland. The very high cost of woodland creation meant that the driver for planting would not be biomass and the contribution to Renfrewshire’s biomass needs would be very low.
  • Category D sites – of which there were only two – had a high percentage of hawthorn scrub and were therefore not suitable for the production of biomass.

To ascertain the attitudes of members of the public on the potential changes to local woodlands, questionnaires were developed and distributed in the Erskine Community Centre. Communication with potential biomass partners was carried out by telephone conversation and the emailing of a questionnaire.

Project outcomes

Of the 52 existing sites (355ha) surveyed, most sites are well-wooded (76% average cover) and the total current standing volume is in the region of 40,000 tonnes (44,000 cubic metres). 20 sites (mostly smaller in size) were considered unlikely to contribute to biomass needs. Many woodlands have a backlog of demands for improvement and have been undermanaged. The initial ‘flush’ from partially restructuring these woodlands to create a diverse age and canopy structure could produce 6000 tonnes (6600 cubic metres) of timber. Most of this would be suitable for biomass. After the woodlands have been restructured and replanted the long term sustainable annual production is likely to be 1200 tonnes (1350m3).

Of the 21 vacant and derelict sites (145ha) surveyed, 10 of the locations were not considered suitable for biomass production (although other drivers / policies may ultimately produce a small volume of biomass from these sites). The 70 hectares considered suitable could produce 943m3 annually once into production – a 10 to 15-year cycle is considered feasible. Most of the suitable sites would be managed for short rotation coppice of Aspen; Red alder; Ash (subject to disease); Willow; Eucalyptus & Birch.

The local community – as evidenced in the results of the questionnaire - did not object to a proportion of the woodland being managed more intensively for biomass and were not concerned about the prospect of timber harvesting. Most would like to see more active management – especially if this enabled general maintenance. Communities were in favour of the use of smaller-scale machinery which provides local employment opportunities. A list of potential contacts for partnerships was also compiled.

CSGN Support and Learning

Renfrewshire’s Biomass Feasibility Study aimed to enhance the Central Scotland Green Network by reducing the amount of vacant and derelict land through the strategic extensions of woodland cover. The study sought to create a place in the balance by planting trees to capture CO2. The study also sought to create a place for nature by diversifying the structure of woodland sites to boost biodiversity.

Future development of project

Renfrewshire council owned woodland sites are at the expensive end of the working costs scale. Timber (biomass) harvesting, haulage and infrastructure costs would not make the project viable. These costs can be brought down with woodland restructuring and new planting on vacant and derelict land sites which would reduce the longer-term supply cost. However, this would require significant capital investment.

The conclusion was reached that the decision on progressing biomass-based energy schemes within Renfrewshire Council should not be based on the possible production from Council-controlled woodland. Renfrewshire Council instead plan to organise a biomass grower, supplier and user collaboration event to establish that critical mass is achievable in demand, process and timber supply to support investment in all three areas.

Funding Details:

Year Fund Value
2015 CSGN Development Fund 22,500

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