Multi Objective Decision Making: a guidebook approach

Transcription

1 Multi Objective Decision Making: a guidebook approach Peter Pearson & Tim Foxon, Environmental Policy & Management Group, T H Huxley School, Imperial College, London Abstract The paper describes one recently-completed and one ongoing research project. The first project, the Reference Sustainability System, is a network model that investigated new technological and resource management strategies to enhance urban sustainability. Based on data for the domestic sector in London, it developed modules relating to energy, paper and waste paper, piped water and bottled water. This research demonstrated the potential value of going beyond modelling, to the development of decision supporting tools/frameworks that take into account user needs and stakeholder perspectives. The second part of the paper describes the current project, which develops a guidebook approach to multi objective decision making by water authorities. The guidebook will offer a framework that aids the incorporation of sustainability assessment in decision making. It will provide guides to the selection and use of a range of environmental, social, technical and economic criteria, as well as to the tools and assessment methodologies that can assemble or generate appropriate data. Then, through two case studies, the use of the guidebook to aid decision making will be demonstrated. Multi Objective Decision Making: a guidebook approach Peter Pearson & Tim Foxon Environmental Policy & Management Group T H Huxley School Imperial College 1

2 The Structure of the Paper The paper describes one recently-completed and one ongoing collaborative research project. The first project the Reference Sustainability System is a network model that investigates new technology & resource management strategies to enhance urban sustainability. The second project relates to the development of a guidebook approach to water authority decision-making. Both projects have received support from the UK Engineering & Physical Sciences Research Council Background: The Reference Sustainability System A network model constructed by Imperial College with the London Research Centre The model investigated technology & resource management strategies to enhance urban sustainability Four related modules: energy; piped water; bottled water; paper & waste paper Allowing for: waste management, recycling & re-use emissions of air, water & solid wastes Addressed domestic/household sector in London Conventional & novel technologies and varying efficiencies 2

3 The Modules The modules were used to assess the system-wide impacts of new technologies or resource management strategies applied at different stages in the life-cycle: the energy module assesses supply-side technologies and enduse efficiency measures the piped water module assesses demand management measures; and the bottled water and paper modules focus on options at the waste management stage. Scenario Outline (Figure 1) Scenarios were created for the introduction of new technologies and resource management practices at different life-cycle stages Baseline and alternative scenarios were compared, at a point in time and/or over time Sensitivities to different rates of penetration of new technologies and resource management practices were explored As were sensitivities to different estimates of environmental externality valuation 3

4 Figure 1: The Reference Sustainability System: Scenario Outline Life-Cycle Stages Supply-Side Demand-Side Waste Management Energy Energy, Water Bottled Water Resource, & Material Paper Flows Scenario Option Scenario and Sensitivity Analysis Runs [Energy] No ext. values Low ext. values High ext. values Externality Scenario 1: EP65 data EP65 data EP65 data Valuation Baseline Scenario 2: Increase Low Pen. Photo-Voltaics Med. Pen. Scenario 3: Scenario 4: Scenario 5: Scenario 6: Scenario 7: Composite Scenarios High Pen. Low Pen. Med. Pen. High Pen. Low Pen. Med. Pen. High Pen. Technology Penetration Reference Sustainability System: The bottled mineral water module Resource Conversion 1 Conversion 2 Conversion 3 Transport End-use Service Imported bottled water Indigenous source of mineral water Plastic raw materials 409 kl/day Imported bottled 229 (kl/day) 87 t/day water at UK depot 8 (t/day) 98 (kl/day) 59 (t/day) 1266 kl/day 0 Collected mineral 1013 water 0 (kl/day) 0 Plastic 0 Plastic bottle Household Plastic bottled water Plastic bottled water 0 kl/day (t/day) processing 0 manufacture (t/day) 0 8 demand for PB distribution 0 water PB water - short life 0 0 t/day 0 Plastic PB waste recycling 0 PB community 0 t/day reprocessing 0 collection point Low-grade resale PB waste landfill 0 0 t/day PB waste kerbside PB waste incineration 0 collection 0 t/day Municipal landfill 0 PB waste municipal Glass raw materials Glass bottle Glass bottled water 1111 Household 1111 kl/day Glass processing Glass bottled water (t/day) (t/day) manufacture distribution 667 demand for GB 667 t/day 0 kl/day water 0 t/day 180 GB waste reuse 0 GB community -180 t/day Glass reprocessing -200 t/day GB waste recycling GB waste landfill collection point GB waste kerbside collection -387 t/day GB water - short life

5 RSS contribution Extended RES & enhanced LCA approach by applying it in a dynamic system flow context - to London Applied sustainability criteria and showed: Conceptual & practical complexities of indicators & valuation how assessment depends on decision-maker & stakeholder perspectives Next stages? Build on RSS-type models to develop useful decision-supporting tools/frameworks? What do users need to help sustainability assessment? Led to collaborative project, with decision support tools a key focus Decision-support Project The development of a decision-support tool to assess the relative sustainability of water/wastewater systems Supported by the UK Engineering and Physical Sciences Research Council WITE Programme: Imperial College, University of Abertay, Dundee, Heriot-Watt University North, East, West of Scotland Water Authorities, Severn- Trent Water 5

6 Ways forward for sustainability Formulating environmental, social and economic criteria: stakeholder input Analysis of options: systems modelling tools and social impact assessment Assessment of relative sustainability: multi-criteria analysis Decision-support system/guide Project process Learn about how water utilities currently make decisions Focus groups with water authority/company managers Decision mapping exercises: map information flows and criteria used identify decision nodes Specification of criteria Development of the Guidebook 6

7 Framework for decision-support Process modelling Decisions Multicriteria analysis Sustainability indicators/ criteria Systems modelling Scenarios Social analysis Guidebook: framework for incorporating sustainability assessment into decision making Guide to criteria Guide to tools and assessment methodologies Guide to appropriate data Demonstration projects 7

8 Selection of criteria Formulation of generic criteria: environmental, social, economic, technical developed in collaboration with water industry & stakeholders End-user may select appropriate criteria for evaluation of decision options Economic and environmental criteria Economic Life-cycle costs Willingness to pay/price responsiveness Affordability Financial risk exposure Environmental Resource utilisation Service provision Environmental impact 8

9 Social and technical criteria Social Acceptability to stakeholders Participation and responsibility Public awareness and understanding Social inclusion Technical Performance of the system Reliability Durability Flexibility and adaptability Components of economic life-cycle costs Life Cycle Costs -stages Resource extraction Production End-use End of life/ Decommissioning (inc. Green costs ) o Cost components: Capital Operation (O) Maintenance (M) Cost categories Marginal; Average; Total 9

10 Components of willingness-to-pay/ price responsiveness Attributes Product Environmental Safety Health Other Tools for analysis of options by Guidebook users Systems modelling tools for economic and environmental impact Social impact assessment: stakeholder workshops, etc. Technical assessment (generation of data for technical criteria) 10

11 Assessment of sustainability Scoring options according to criteria Either: compare with indicators of sustainability Or: use Multi-Criteria Analysis to assess trade-offs between different criteria Different stakeholders may assign different weights to criteria Implications of these weightings Post-decision phase Implement decision Monitor and evaluate option chosen Feedback refined criteria and evaluation of process into decision-support procedure Open and transparent process 11

12 The Guidebook Process Review performance Proposed 'activity' Define decision objectives & Determine options phase 1 DEFINE OPTIONS Select pertinent criteria from generic set phase 2 SELECT CRITERIA Collect data All necessary data available including analysis (temporal etc) Not all data available Carry out relevant analysis using appropriate tools Measure ments, models etc. Match data with criterias for each option phase 3 ANALYSE EACH OPTION - DATA ASSEMBLY Rank options/criteria descriptors Define indicators INDICATORS Ranking/ indicators or MCA? MCA phase 4 RANK OPTIONS Compare options/data with indicators Apply formalised MCA MORE SUSTAINABLE OPTION DETERMINED phase 5 ASSESS RELATIVE SUSTAINABILITY phase 6 IMPLEMENT Further Reading Leach MA, Bauen A and Lucas NJD (1997). 'A Systems Approach to Materials Flow in Sustainable Cities. Case study of paper'. Journal of Environmental Planning and Management, 40(6), Foxon TJ and Leach MA, with Butler D, Dawes J, Hutchinson D, Pearson PJ and Rose D (1999). Useful indicators of urban sustainability: some methodological questions, Local Environment, 4(2), Foxon,T J, Butler, D, Dawes, J, Hutchinson, D, Leach, M, Pearson, P and Rose, D (2000, forthcoming), An assessment of water demand management options from a systems approach, Journal of Chartered Institute of Water and Environmental Management. Francois Bouchart, Tim Foxon, Nicki Souter, Richard Ashley, David Butler and Paul Jowitt (1999): Decision mapping for the development of multi-criteria analysis tools to assess the relative sustainability of water/wastewater systems, CHAINET (European network on chain analysis for environmental decision support): 12