The Waste sector is incorporated as a potential source of energy input to other sectors. Scottish Government policies around reducing waste are also captured in the declining waste emissions envelope. The envelope was generated using the Scottish waste emissions model, and was coded into TIMES.
Data inputs and additional constraints since the Draft Plan:
The waste emissions model has been updated for the latest Greenhouse Gas Inventory, with the emissions profile in future years adjusted to reflect this update.
Since the draft Climate Change Plan, tonnages of organic and inorganic municipal solid waste, wet biomass waste and landfill gas, available as resource inputs to the model, have been updated to be in line with data from Zero Waste Scotland, thereby ensuring that the volume of waste that can be drawn on to satisfy energy demand is consistent with Scottish Government waste targets. Availability estimates for sewage sludge and animal slurry have been updated to reflect the latest data from a study commissioned by BEIS from Ricardo, scaled to Scotland using total waste availability in Scotland, relative to the UK from the Scottish Environment Protection Agency ( SEPA) and the UK Department for Environment, Food and Rural Affairs ( DEFRA), and cattle numbers from the Scottish Agricultural Census.
The figure below shows how waste in used throughout the period of the Plan. Some waste goes directly to the sectors, where it feeds directly into energy generation technologies; some is used upstream of the sectors in anaerobic digestion ( AD) plants, the output of which is upgraded to biomethane and injected into the gas grid. The quantity of waste used increases to 2025, falling back to around 2.8 TWh per annum from 2030, with industry consuming the largest proportion. The higher volume used in 2025 is down to use of municipal solid waste in Industry, as fuel in combined heat and power ( CHP) steam turbines, which, in later years, shifts to using non-waste biomass feedstock.
Figure 18: Waste Use by Sector ( TWh), TIMES model run
In the industrial sector, waste is primarily used as a heat source and in Combined Heat & Power. Waste is also used as fuel in waste combustion plants to generate electricity. Over the period waste accounts for around 2% increasing to just under 3% of all primary energy supplied to the system.