Greatmoor Energy from Waste Facility. Carbon Footprint Assessment

Transcription

1 Greatmoor Energy from Waste Facility Carbon Footprint Assessment August 2010

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3 WRG i CONTENTS 1.0 INTRODUCTION METHODOLOGY RESULTS Characterising Environmental Impacts Global Warming Potential Comparison of Greatmoor EfW against Global Warming Potential Comparison of Alternative Waste Treatment Technologies CONCLUSIONS CLOSURE... 7 Appendix A APPENDICES Process Flow Diagrams of Treatment Scenarios P:\Project\WRG \ Calvert EfW 2010\Tech\PE\Output\Ext\Sep Final\ES Sep Final\Chapter 14 Climate Change\Appendices\100826_ _Greatmoor-WRATE-Report_App 14-A.doc

4 WRG INTRODUCTION This report outlines the main assumptions, results and interpretation of a carbon footprint and Life Cycle Assessment analysis to support the planning application for the Greatmoor Energy from Waste (EfW) Facility. The Greatmoor EfW would use established energy from waste direct combustion technology provided by the Swiss firm AE&E Inova. It is designed to manage up to 300,000 tonnes per annum of residual municipal, commercial and industrial waste. 2.0 METHODOLOGY The Environment Agency life cycle assessment software Waste and Resource Assessment Tool for the Environment (WRATE) has been utilised to model the potential environmental impacts of the proposed facility. The WRATE 1 software is a life cycle assessment tool specifically designed to model the environmental impacts of waste and waste management processes. Its use is endorsed and encouraged by the Environment Agency (EA) and Department for Environment, Food and Rural Affairs (Defra). In summary, the environmental burdens for global warming potential have been calculated for the processing of 300,000 tonnes per annum of residual municipal, commercial and industrial residual solid waste through a number of waste treatment processes: Energy from Waste (EfW) with power export 2 ; Advanced Thermal Treatment (ATT), specifically Pyrolysis 3 ; Mechanical Biological Treatment (MBT) with Refuse Derived Fuel (RDF) to EfW 4 ; and Mechanical Biological Treatment (MBT) with biostabilised output to landfill 5. The assessment compares the potential environmental impacts of the proposed solution, Energy from Waste, against three other waste treatment processes, as well as landfill 6, as the baseline scenario. The commercial and industrial (C&I) wastes destined for treatment at the facility are likely to be those included under the Environment Agency (EA) heading mixed waste, as outlined in the EA Strategic Waste Management Assessment 2002/03 survey of C&I waste. A recent study by Consulting for the Environment Agency Wales 7 demonstrates that the mixed commercial and industrial waste stream is similar in composition to municipal waste. For this reason, the use of the WRATE default municipal waste composition (Figure 2-1) to characterise the C&I wastes is deemed suitable for the purposes of this comparative technology assessment. The municipal waste composition is as defined in the Buckinghamshire County Council (BCC) WRATE procurement model; this has been maintained to provide consistency between WRATE outputs WRATE process Incinerator medium, power CHINEHAM v2 (22400) a User Defined Process developed by Ramboll for use by WRG in the Buckinghamshire County Council procurement process 3 WRATE process - Pyrolysis (MSW and RDF) WASTEGEN process (21252) 4 WRATE process - MBT bio-drying &RDF ECODECO process (11216) and Incinerator medium, power CHINEHAM v2 (22400) developed by Ramboll 5 WRATE process - MBT bio-drying &RDF ECODECO process (11216) and (Clay Liner, Clay cap) (12255) 6 WRATE process (Clay Liner, Clay cap) (12255) 7

5 WRG Non-combustibles 8% Figure 2-1 WRATE default waste composition used for C&I Waste Combustibles 7% Glass 6% Fine Material 5% Ferrous 5% Dense Plastic 5% Plastic Film 3% Wood 3% Paper & Card 20% Organics 30% Other 13% Absorbant Hygiene Products 2% WEEE 2% Textiles 2% Specific Hazardous Household 1% Non-ferrous 1% Since a number of the waste management processes produce electricity an assumed energy mix must be defined in order to calculate the avoided burdens (from not having to produce the electricity from traditional generation methods). WRATE has default energy mixes for the UK available; the energy mix for the year 2016 has been selected, this was the year utilised in the BCC WRATE procurement model. The year 2016 is a suitable assessment year at which time, if planning permission is granted and the necessary environmental permits obtained, the treatment facility would be constructed and fully operational. WRATE contains a number of default technology templates; these have been used as the basis of the 5 waste management scenarios. For example, the ECODECO system has been utilised to model the MBT scenarios. The technology solution for the Greatmoor EfW is based on the default Chineham incinerator template; a number of modifications were made by Ramboll to ensure that the process best represents the proposed technology. Modifications to the technology process included changing the proportions of product outputs, changes to the quantity of energy generated, modifying the consumables and air emissions. The outputs from WRATE are life cycle impact assessment (LCIA) indicators; these can be specified by the user and measure the potential impacts of the waste treatment scenarios. Section 3.0 of this report presents the Global Warming Potential (GWP 100), commonly referred to as Carbon Footprint, and a basic scoring mechanism to assist in the comparison of the selected waste management scenarios. The scores are derived by normalising the overall performance scores on a scale of 0 to 1, where 0 represents the worst scenario and 1 represents the best scenario. Using this methodology, the higher the score the more sustainable the option is considered to be. Sankey flow diagrams for each of the scenarios are presented in Appendix A.

6 WRG RESULTS 3.1 Characterising Environmental Impacts The WRATE software uses a life cycle, or gate to grave approach to estimate environmental impact. For the purpose of modelling waste management technologies this requires the identification and quantification of the following environmental impacts: Direct Burdens - defined as emissions from the process itself, for example carbon dioxide as a consequence of combustion or aerobic degradation; Indirect Burdens - associated with the supply of energy and materials to the process, for example construction materials, electrical energy for motors and fans and chemicals for pollution abatement equipment; Avoided Burdens - associated with the recovery of energy and materials from the waste stream resulting in the avoidance of primary energy production, and mineral extraction. 3.2 Global Warming Potential Comparison of Greatmoor EfW against The carbon footprint of the baseline scenario (waste to landfill) is compared against the EfW process in Figure 3-1. ing of waste exhibits a clear environmental burden when compared to EfW as an alternative treatment; EfW demonstrates not only a reduction in carbon footprint, but an avoided burden of CO2e emissions. Figure 3-1 Life Cycle Global Warming Potential The results in Figure 3-1 illustrate the carbon footprint of the proposed Greatmoor EFW generating electrical power only. The EfW scenario results in a net avoided environmental burden of circa -53,000,000 kg CO2e. on the other hand results in a net carbon

7 WRG burden of circa 62,000,000 kg CO2e. The Greatmoor EFW could accrue further carbon savings through operation in Combined Heat and Power (CHP) mode. The exact performance, and thus carbon saving, would be dependent on the ratio of electricity to heat off takes. Figure 3-2 shows the scenarios sub-divided into direct emissions, indirect emissions and avoided emissions to provide further analysis of the main sources of environmental burdens and avoided burdens. Figure 3-2 Direct, Indirect and Avoided Life Cycle Global Warming Potential Direct burdens result from the direct processing of waste in the landfill or EfW process; for landfill the direct emissions are attributable to fugitive methane emissions and for EfW the combustion products of plastics and other fossil fuel derived materials are the main contributory factors. Indirect burdens result from construction, maintenance, energy input and operational materials. The energy from waste process exhibits more significant indirect impacts than landfill, as a consequence of operational material inputs (chemicals for gas and water treatment) which exhibit high embodied energy contents due to the significant degree of processing required. Avoided burdens include the benefits of recycling materials (for example metals or incinerator bottom ash) and generation of electrical power. The landfill scenario exhibits an avoided burden associated with the capture of landfill gas (methane) and subsequent combustion to generate electricity via on site gas turbines. The avoided burdens for EfW are considerably greater, and these are associated with recycling and the electrical energy generation. Electricity generation offsets the extraction, processing and combustion of fossil fuels resulting in an avoided environmental burden.

8 WRG Global Warming Potential Comparison of Alternative Waste Treatment Technologies The following section presents the results of the global warming potential of alternative waste treatment technologies and compares the environmental impact against the proposed Greatmoor EFW and to landfill. The net global warming potential results are presented in Figure 3-3; those scenarios represented by red bars indicate a positive burden to the environment, whilst scenarios represented by green bars indicate a net avoided burden of carbon dioxide equivalent. Figure 3-3 Global Warming Potential (GWP 100) Impact Results The Global Warming Potential results presented in Figure 3-3 can be explained as follows: Technology Energy from Waste (EfW) with power export Advanced Thermal Treatment (ATT) Justification of Results Combustion of recovered methane generates electricity, which avoids the need to produce electricity from non-renewable (fossil) sources. However this saving is negligible and there is a positive overall impact associated with fugitive emissions of methane and other GWP compounds. EfW releases carbon dioxide from combustion of plastics and other fossil fuel derived materials. Recovered energy avoids the need to produce electricity from non-renewable (fossil) sources which in turn reduces emissions associated with the extraction and combustion of fossil fuels. Recovery of ferrous metals displaces production from virgin materials, and subsequently reduces energy requirements. ATT releases carbon dioxide from the processing of plastics and other fossil fuel derived materials. Recovered energy avoids the need to produce electricity from non-renewable (fossil) sources which in turn reduces emissions associated with the extraction and combustion of fossil fuels. Recovery of ferrous metals displaces production from virgin materials, and subsequently reduces energy requirements.

9 WRG Technology Mechanical Biological Treatment (MBT) with Refuse Derived Fuel (RDF) to EfW Mechanical Biological Treatment (MBT) with biostabilised output to landfill Justification of Results The energy production from ATT is lower than that proposed for Greatmoor EFW, leading to ATT scoring worse than EfW energy export only overall. Recovery of ferrous metals, non ferrous metals and glass displaces production from virgin materials, and subsequently reduces energy requirements. Benefits are less than those for EfW only, despite the increase in calorific value, the additional burdens associated with construction of the MBT facility, the rejects sent to landfill, higher electricity input for operation of front end equipment and due to the formation of nitrous oxide from the biological oxidation of nitrogen containing compounds. Recovery of recyclable ferrous metals, non-ferrous metals and glass from front end processing displaces production from virgin materials, and subsequently reduces energy requirements. The positive burden is associated with fugitive emissions of GWP compounds from the RDF material consigned to landfill and nitrous oxides from the biological oxidation of nitrogen containing compounds. All residual treatment technologies result in reduced CO2e emissions compared to landfill, the baseline scenario. Three scenarios (EfW power export, ATT and MBT with EfW) outperform the other scenarios and result in a net avoided burden of carbon dioxide equivalent, i.e. the avoided burdens of recycling and energy recovery outweigh the burdens of carbon dioxide from the direct and indirect emissions. The estimated Global Warming Potential of the 5 waste treatment scenarios is tabulated in Table 3-1; the GWP emissions are valued to provide a score of between 0 and 1, with 1 representing the most sustainable waste treatment technology. Table 3-1 indicates that EfW outperforms all other scenarios with respect to the Global Warming Potential. The lowest performing technology is landfill with a value score of 0. All technologies result in a reduction in environmental impact compared to landfill (the baseline situation). Table 3-1 Global Warming Potential Performance & Valued Scores Baseline () Greatmoor EFW ATT (Pyrolysis) MBT with EfW MBT with kg CO2 eq. 61,683,709-53,115,496-25,099,546-45,302,349 11,633,064 valued score Note: For valued scores 1 represents the most sustainable option, and 0 represents least environmentally sustainable.

10 WRG CONCLUSIONS This report presents the global warming potential 8 (commonly known as carbon footprint) for the processing of 300,000 tonnes of residual waste through a number of different residual waste treatment processes. Modelling has been carried out using the Environment Agency s Life Cycle Assessment Tool, WRATE. The WRATE modelling results indicate that, the best performing option with respect to Global Warming Potential is Energy from Waste. In conclusion, the WRATE modelling indicates that the Greatmoor EFW will deliver a reduction in carbon emissions compared to landfill. Furthermore, the chosen technology, EfW, is shown to outperform other waste management solutions. In conclusion, through the use of the WRATE life cycle assessment software, it can be demonstrated that Energy from Waste, yields a carbon footprint impact that is superior to the other competing technologies. On this basis it is concluded that the proposed Greatmoor EFW will result in a net negative environmental footprint, that is, an overall reduction of CO2e emissions compared to landfill. 5.0 CLOSURE This report has been prepared by Consulting Limited with all reasonable skill, care and diligence, and taking account of the manpower and resources devoted to it by agreement with the client. Information reported herein is based on the interpretation of data collected and has been accepted in good faith as being accurate and valid. The conclusions presented herein are relevant to, and only to, the set of assumptions that form the basis of the Life Cycle Assessment modelling. The results of this modelling should not be used to infer benefits for other similar, but unrelated projects. This report is for the exclusive use of WRG; no warranties or guarantees are expressed or should be inferred by any third parties. This report may not be relied upon by other parties without written consent from. disclaims any responsibility to the client and others in respect of any matters outside the agreed scope of the work. 8 WRATE Life Cycle Impact Assessment - Default Impact Assessment, Global Warming (GWP100)

11 WRG ANNEX A: PROCESS FLOW DIAGRAMS OF TREATMENT SCENARIOS Figure A-1 Process Diagram CDC Residual Waste (13,173 t) AVDC Residual Waste (31,989 t) SBDC Residual Waste (12,728 t) WDC Residual Waste (28,748 t) HWRC (22,728 t) C&IW Figure A-2 Energy from Waste (EfW) Process Diagram Aluminium CDC Residual Waste (13,173 t) Metals transport Ferrous AVDC Residual Waste (31,989 t) WRG EfW OTHER IBA Recycling SBDC Residual Waste (12,728 t) Calvert Haz. WDC Residual Waste (28,748 t) HWRC (22,728 t) C&IW

12 WRG Figure A-3 Advanced Thermal Treatment (ATT) Process Diagram CDC Residual Waste (13,173 t) AVDC Residual Waste (31,989 t) SBDC Residual Waste (12,728 t) Pyrolysis WDC Residual Waste (28,748 t) OTHER IBA Recycling HWRC (22,728 t) C&IW Figure A-4 Mechanical Biological Treatment (MBT) with Refuse Derived Fuel (RDF) going to Energy from Waste (EfW) Process Diagram Glass CDC Residual Waste (13,173 t) Ferrous AVDC Residual Waste (31,989 t) Aluminium SBDC Residual Waste (12,728 t) Mechanical Biological Treatment WDC Residual Waste (28,748 t) EfW OTHER IBA Recycling HWRC (22,728 t) C&IW

13 WRG Figure A-5 Mechanical Biological Treatment (MBT) with Refuse Derived Fuel (RDF) going to Process Diagram Glass CDC Residual Waste (13,173 t) Ferrous AVDC Residual Waste (31,989 t) Aluminium SBDC Residual Waste (12,728 t) Mechanical Biological Treatment WDC Residual Waste (28,748 t) -1 HWRC (22,728 t) C&IW