Biomass Waste EFW
The generation of energy from Biomass covers a broad range of input materials and technologies for recovering the energy - from Combustion and ERF of waste based Biomass such as Wood Waste to Combustion of dedicated crops and virgin materials such as wood, and the indirect recovery of energy from Anaerobic Digestion of food and crops. Indeed Residual Waste EFW does itself have an element of Biomass and this can also be considered to the degree that this is the case.
Overview
Different Biomass can be used as a feedstock for Energy from Waste processes. The table below summarizes the types of Biomass used in 2017 to generate energy (excluding the Biomass content of Residual Waste in Residual Waste EFW [1]. EfW plants that operate using Biomass as a feedstock can be considered as producing Renewable Energy[2]. Biomass can be considered a renewable fuel because the growth of Biomass removes carbon dioxide from the atmosphere and stores it in components of Biomass such as soil, plants and trees, acting as temporary carbon storage[3]. Biomass is the largest source of renewable energy in the UK[3].
| Biomass | Overview | Tonnage (mt) '16-'17 | Power Generated (GWh) '16-'17 |
|---|---|---|---|
| Wood Waste | As of Qtr 1 2019 there are currently 23 Wood Waste facilities operating in the UK with another 3 taking a combination of Wood Waste and Virgin Wood and one a mixture of Wood Waste and MBM; 7 facilities are currently under construction | 1.63 | 1273 |
| Meat and Bone Meal (MBM) | As of Qtr 1 2019 there are only two main facilities treating this waste stream with a third due on line at some point in the near future | 0.18 | 145 |
| Agricultural Waste | There are four plants currently in operation treating in the region of 1.0Mtpa with the dominant markets for straw (animal bedding/feed) taking up around 80% of supply. Poultry Litter is sent to three large scale facilities with remaining tonnage sent to AD facilities and used in agriculture as a fertilizer. | 1.37 | 1225 |
| Sewage Sludge | Now managed exclusively in the UK as part of waste water integrated treatment process by the Sewerage Undertakers (two plants operated by Thames Water and the third by United Utilities). The trend in the sector is increasingly to use advanced AD to extract energy from the Biogas generated. | 0.10 | 23 |
| Process Residues | By-products from processing all forms of biomass that have significant energy potential and include kernels, shavings, sawdust, chaff) etc | 0.09 | 45 |
| Liquid Biomass | Also known as Biofuel and is any kind of liquid produced from solid matter | NA | NA |
| Virgin Wood & Energy Crops | There are currently 15 biomass facilities in operation taking Virgin Wood with another four taking a combination of Wood Waste and Virgin Wood; two remain under construction | 2.36 | 1516 |
| Total | 5.73 | 4226 |
Image above taken from Tolvik Biomass report[1] representing the main plants handling the tonnage summarized in the table above.
Biomass EFW Sites
In 2017, there were 39 operational Biomass EfW facilities in the UK with an electrical output exceeding 2.5 MW; the total Biomass capacity of these plants is 5.73 Mt (excluding fuel imported by Drax), and these plants combined produced 4,226 GWh of power. The Biomass capacity of UK EfW plants is generally increasing, and from 2016-2017 the amount of Biomass being processed by UK facilities increased by 6.9%[1].
An example of a Biomass EfW facility in the UK is Welland Bio Power in Northamptonshire, accepting 72,000 tonnes of waste wood per year, and producing 10.6 MWe (gross) of electricity. Welland Bio Power utilizes Nexterra Gasification technology and was developed by CoGen Limited[4].
Biomass in Residual Waste EFW
Energy from Waste plants that use Waste Derived Fuel (WDF) but do not exclusively accept Biomass will still have a portion of Biomass in their feedstock. Often this is quantified as the amount of the C-14 isotope in the fuel compared to total carbon in the feedstock. This is an important parameter as the heat/electricity produced from an EfW plant that can be classified as renewable (and therefore eligible for subsidies e.g. ROC, RHI) is derived from the biogenic portion of the feedstock. This quantity of biomass in the feedstock also forms the basis of the Renewable Qualifying Multiplier (RQM) to calculate the quantity of payments made to a generator in line with the Contract for Difference (CfD) scheme[5].
The non-biomass portion of waste feedstock (e.g. plastics) produce a similar product gas to biomass-derived gas. Additionally, they both have similar fuel characteristics, like high volatile matter content and low fixed carbon content. Subsequently, this enables similar processing conditions and gas cleaning techniques to be used in waste and biomass EfW facilities. However, significant differences do still exist between these two feedstocks, for example, generally higher ash content and higher content of other contaminants in a mixed waste feedstock and these warrant specific changes in the EfW process[6] and lead to more stringent control systems to ensure compliance with the Industrial Emissions Directive.
References
- ↑ 1.0 1.1 1.2 Tolvik Consulting Ltd, 2017. UK Dedicated Biomass Statistics - 2017. [online] [Accessed 13 Nov. 2019].
- ↑ Defra, 2014 in proportion to the amount of Biomass used in line with the ROC and CFD regimes.Energy from waste A guide to the debate February 2014 (revised edition). London.
- ↑ 3.0 3.1 Office for National Statistics, 2019. A burning issue: biomass is the biggest source of renewable energy consumed in the UK - Office for National Statistics. [online] Office for National Statistics. [Accessed 14 Nov. 2019].
- ↑ CoGen, 2019. Projects — CoGen. [online CoGen.] [Accessed 14 Nov. 2019].
- ↑ LCCC, 2019. Contracts for Difference Generator Guide. Low Carbon Contracts Company. London.
- ↑ Waldheim, 2018. Gasification of waste for energy carriers. A review. IEA Bioenergy, [online] ISBN 978-1-910154-56-4. p.16. [Accessed 14 Nov. 2019].