Mapping Carbon Storage and Potential Bioenergy Production in Södertälje Using High-resolution Biotope Database

Abstract: Global warming is caused by the human induced increase of Greenhouse Gases (GHG) in the atmosphere. GHG emissions need to be reduced, and carbon dioxide (CO2) emissions from fossil sources ceased to mitigate global warming. Energy production and use is a main contributor to fossil sourced emissions in Europe. Sweden has a high part renewable power production but not completely, to have a 100% renewable power production by 2040 is a goal set by Swedish government. By 2045 Sweden also plans to have net zero emissions nationwide and afterwards negative emissions of CO2, to reduce global warming and reach the Paris agreement of maximum 1.5°C global warming level it is urgent and vital to create Carbon (C) sinks and to reach neutral and even negative emissions within the energy sector. Negative emissions can be reached in Combined Heat and Power plants (CHP) by Bio Carbon Capture and Storage (Bio-CCS). Demand on wood chips and bio-energy fuel is increasing on the European continent. A local source of biofuel might contribute to shorter transports, a local C-sink, security in supply and a way to meet both the increasing competition of fuel and the environmental political targets. Here we investigate the available land for local production of bioenergy forests in Södertälje and the amount of energy possible to produce from that. Using a detailed biotope database over the municipality, Biotopdatabasen, and a Geographical Information System (GIS) based approach 5 scenarios of potential land areal for planting of energy forests in the municipality have been analysed. Different criteria selections in biotopes, grasslands and historical crop fields, and land use, used or un-used, builds the scenarios; 1. All available grasslands, 1010 ha, 2. All available grasslands on earlier crop fields, 815 ha, 3. Unused available grassland on earlier crop field, 300 ha, 4. Available land on earlier crop fields, including forestry, 1715 ha, 5. Unused available land on earlier crop fields, 366 ha. Gross annual energy yields from energy forest in the scenarios were estimated to; 1. 46,2-65,1 GWh/y, 2. 37,3-52,5 GWh/y, 3. 13,7-19,3 GWh/y, 4. 78,4-110,5 GWh/y, 5. 16,7-23,6 GWh/y. The yield from all these scenarios will, in the expected gross normal yield scenario, match the energy produced today by fossil fuels in the local CHP and heating plant (0.64%, 2020) yields 0.69-3.96% of total energy produced. Scenarios 3 and 5 are considered likely scenarios but the effect on spreading pathways and thereby biodiversity needs to be assessed, using old crop fields lowers the risk of harming important biodiversity and possibly help restore C sink in soils.