Calculating carbon savings from wind farms on Scottish peat lands - A New Approach

DescriptionA New Approach has been developed to calculate the impact of wind farm developments on the soil carbon stocks held in peats. This provides a transparent and easy to follow method for estimating the impacts of wind farms on the carbon dynamics of peat lands.
ISBN
Official Print Publication DateJune 2008
Website Publication DateJune 27, 2008

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Dali Rani Nayak 1, David Miller 2, Andrew Nolan 2, Pete Smith 1 & Jo Smith 1

1 - Institute of Biological and Environmental Sciences, School of Biological Science, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen, AB41 3UU
2 - Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen AB15 8QH

Project funded by the Rural and Environment Research and Analysis Directorate of the Scottish Government, Science Policy and Co-ordination Division.

The views expressed in this report are those of the researcher and do not necessarily represent those of the Scottish Government or Scottish Ministers

First published June 2008 - ISBN 978 0 7559 7147 3 (Web only publication)

This edition was corrected by the authors in June 2010.

This document is also available in pdf format (1.3mb)

 

Contents

1. Executive Summary

2. Background

3. Objectives

4. General Approach

5. Review of SNH Technical Guidance Document

6. Modelling the Impacts of Construction and Operation of Wind Farms on Peat
6.1. Practices that change carbon emissions from peat lands
6.1.1. Borrow pits
6.1.2. Access tracks
6.1.3. Foundations for turbines and crane pads
6.1.4. Construction of the substation and temporary compounds
6.1.5. Cable trenches
6.1.6. Forestry operations
6.1.7. Restoration of site after decommissioning
6.1.8. Improvement of altered peat lands as part of the habitat management plan
6.2. Fate and treatment of excavated peat
6.3. Drainage features associated with wind farm construction
6.3.1. Drainage of wind turbine foundations
6.3.2. Road drainage
6.4. Summary of factors to be simulated
6.5. Effect of drainage on peats
6.5.1. Impact on peat hydrology
6.5.2. Impact on carbon stocks
6.6. Calculation of the effect of drainage and flooding on peat lands using IPCC default values
6.6.1. Methane Emissions
6.6.2. Carbon Dioxide Emissions
6.6.3. Nitrous Oxide Emissions
6.7. Calculation of the effect of drainage and flooding on peat lands using site specific equations
6.7.1. Derivation of site specific equations
6.7.2. Global sensitivity analysis

7. Recommended revised method for calculating carbon dynamics from peat lands
7.1. Change in carbon dynamics of peat lands
7.2. Loss of carbon fixing potential of peat lands
7.3. Changes in carbon stored in peat lands
7.3.1. Loss of carbon from removed peat
7.3.2. Loss of carbon from drained peat
7.3.3. Loss of carbon dioxide due to leaching of dissolved and particulate organic carbon
7.3.4. Loss of carbon due to peat slide
7.4. Loss/saving of carbon due to forestry clearance
7.5. Carbon dioxide saving due to improvement of peat land habitat
7.6. Soil and plant carbon losses and gains calculator
7.6.1. Instructions Worksheet
7.6.2. Worksheet for input data
7.6.3. Results Worksheet
7.6.4. Loss of carbon fixing potential of bog plants
7.6.5. Total loss of soil carbon dioxide from the soil
7.6.6. Volume of peat removed
7.6.7. Carbon dioxide loss from removed peat
7.6.8. Volume of peat drained
7.6.9. Carbon dioxide loss from drained peat
7.6.10. Emission rates from soils
7.6.11. Losses of dissolved and particulate organic carbon
7.6.12. Carbon dioxide loss due to forestry felling
7.6.13. Carbon dioxide gains due to habitat improvement
7.6.14. Example of how management practices and site selection can impact greenhouse gas emissions

8. Stakeholder workshop

9. Conclusions

10. Acknowledgements

11. References

Appendix 1 - Review of SNH Technical Guidance Note (2003) on Wind farms and Carbon Savings
A1.1. Executive Summary
A1.2. Abstract
A1.3. Background
A1.4. Factors not included in the current SNH Guidance
A1.4.1. Carbon dioxide emissions due to production, transportation, erection, operation, and dismantling of the wind farm
A1.4.2. Carbon dioxide emission from backup power generation
A1.4.3. Peat landslide hazard
A1.4.4. Restoration of the site
A1.4.5. Change in grid-mix and payback time
A1.4.6. Carbon Implications of Forestry
A1.5. Uncertainties in the current SNH Guidance
A1.5.1. Capacity factor or utilisation rate
A1.5.2. Emission factors for other power sectors
A1.5.3. Carbon- fixation capacity of peat land
A1.5.4. Proportion of site lost in wind farm development
A1.6. Recommendations for reducing uncertainties in technical guidance
A1.6.1. Capacity factor
A1.6.2. Grid-mix emission factor
A1.6.3. Extent of the site affected by development
A1.6.4. Estimates of percentage C loss
A1.7. Detailed Comments on the SNH Technical Guidance Document
A1.7.1. Introduction
A1.7.2. Background
A1.7.3. Carbon emissions from electricity generation
A1.7.4. Wind farm carbon emission savings
A1.7.5. Loss of carbon stored on bogs
A1.7.6. Loss of carbon-fixing potential as a result of woodland clearance
A1.8. Suggested approach for calculating carbon dioxide savings associated with wind farms
A1.9. Suggested best practice to improve carbon savings associated with wind farms
A1.9.1. Best Practise
A1.10. References

Appendix 2. Calculating Potential Carbon Losses & Savings from Wind Farms on Scottish Peat lands: a total life cycle perspective
A2.1. Introduction
A2.2. Background
A2.3. Carbon emission savings
A2.4. Carbon emission savings from wind farms
A2.5. Loss of carbon due to production, transportation, erection, operation and dismantling of wind farm
A2.7. Change in carbon dynamics of peat lands
A2.8. Loss of carbon fixing potential of peat lands
A2.9. Changes in carbon stored in peat lands
A2.9.1. Loss of carbon from removed peat
A2.9.2. Loss of carbon from drained peat
A2.9.3. Loss of carbon dioxide due to leaching of dissolved and particulate organic carbon
A2.9.4. Loss of carbon due to peatslide
A2.10. Loss/saving of carbon due to forestry clearance
A2.11. Carbon dioxide saving due to improvement of peat land habitat
A2.12. Calculation of payback time for the example case-study wind farm
A2.14. References

Appendix 3. Report from the Stakeholder Workshop
A3.1. Introduction
A3.2. Background
A3.3. Carbon emission savings from wind farms
A3.4. Loss of carbon due to production, transportation, erection, operation and dismantling of wind farm
A3.5. Loss of carbon due to backup power generation
A3.6. Loss of carbon fixing potential of peat lands
A3.7. Changes in carbon stored in peat lands
A3.7.1. Loss of carbon from removed peat
A3.7.2. Loss of carbon from drained peat
A3.7.3. Loss of carbon dioxide due to leaching of dissolved organic carbon
A3.7.4. Loss of carbon due to peatslide
A3.8. Loss/saving of carbon due to forestry clearance
A3.9. Carbon dioxide saving due to restoration of peat land

Project funded by the Rural and Environment Research and Analysis Directorate of the Scottish Government, Science Policy and Co-ordination Division.

The views expressed in this report are those of the researcher and do not necessarily represent those of the Scottish Government or Scottish Ministers