The importance of a life cycle perspective in designing pavements and buildings

Transcription

1 The importance of a life cycle perspective in designing pavements and buildings Jeremy Gregory Cement Sustainability Initiative Forum October 1-2, 2013 Vancouver, Canada

2 Life cycle thinking is important DUH! How pervasive is life cycle thinking? Slide 2

3 Lower initial costs often take precedence over lower future costs Roads Homes Automobiles Lower initial costs, but higher maintenance costs higher recovery costs higher use costs Slide 3

4 Automobile Life Cycle Impact Fraction Life cycle thinking is missing in policy-making Example: EU End-of-Life Vehicle Directive Material Recovery Targets: As of Jan 1, 2006 As of Jan 1, 2015 Reuse & Recycling 80% 85% Reuse & Recovery 85% 95% 100% 80% 60% 40% 20% Cumulative Energy Global Warming Where should efforts be focused to reduce life cycle environmental impacts? What is the effect on the use phase of increasing recyclability? 0% Funazaki et al, JSAE Review, 2003 Production Use End-of-Life Slide 4

5 What are barriers to expanding life cycle thinking? It is difficult to deal with trade-offs in decisions Global Warming Potential Environmental Toxicity Resource Scarcity Environmental Impact Factors in decisions With so many trade-offs to consider in a decision, priorities must be made Cost Performance Use costs Initial cost Maintenance costs Safety Reliability Noise Slide 5

6 Why is life cycle thinking a low priority? There is a chasm between life cycle research and practice Life cycle analysis literature and tools Designers, consumers, policy-makers Typical reasons for not using life cycle thinking: 1. It is too hard/expensive 2. There is no demand This means it is a low priority Slide 6

7 We need a carrot and stick approach to make life cycle thinking a higher priority Sticks: Regulations Codes Contracts Carrots: Incentives Standards Social pressure Simple tools Changing paradigms involves technical, management, and social issues Slide 7

8 Life cycle considerations should be analyzed early in the design process Major Influence Rapidly Declining Influence Low Influence Planning & Programming Schematic Design Design Development Construction Documents Construction Tools should facilitate early consideration of life cycle issues Slide 8

9 There are multiple mechanisms for reducing environmental impact across a structure s life Materials Production Use recycled materials Lower energy use Design & Construction Use less (i.e., stronger) material Create longerlasting designs Use Buildings: lower energy consumption Pavements: lower fuel consumption End-of-Life Enable material recovery Prioritizing mechanisms requires analysis of complete life cycle environmental impacts and costs Slide 9

10 The CSHub is working on carrots (i.e., tools) Pavements Buildings Key Objectives Improve scientific basis for models Incorporate uncertainty and risk into analyses Streamline processes Integrate LCA & LCCA into design process Credibility Practicality Slide 10

11 Life cycle considerations for pavements Life cycle assessment Environmental Impact Factors in decisions Cost Life cycle cost analysis Performance (Pavement design process) Slide 11

12 Life cycle assessment of pavements Incorporating use phase in pavement LCA is a recent innovation Scope includes all effects attributable to the pavement design. Extraction and production Transportation Materials Onsite equipment Construction Pavement-Vehicle Interaction Roughness Deflection Albedo Carbonation Lighting Use Maintenance Excavation Landfilling Recycling Transportation End-of-Life/ Rehabilitation Materials Construction Slide 12

13 Model-based assessment of PVI Pavement Deflection MIT-Model Pavement Roughness MEPDG+HDM4 Structure and Material Deflection & Roughness Fuel consumption Environmental Impact Slide 13

14 GWP (Mg CO2e/mi) Case study: urban interstate HW in Arizona Contribution of different phases 95 th Total Initial const. Use phase M & R End of Life 75 th median 25 th th AC PCC AC PCC AC PCC AC PCC AC PCC AC PCC Use phase is a significant driver of impact Slide 14

15 GWP (Mg CO2e/mi) Focus on use phase Contribution of use phase components 95 th Carbonation Lighting Fuel loss: Fuel loss: Albedo IRI deflection 75 th median 25 th 5 th AC PCC AC PCC AC PCC AC PCC AC PCC AC PCC Use phase drivers are highly dependent on pavement design and context Slide 15

16 Use phase should be important consideration in reducing pavement life cycle impact Materials Production Use recycled materials Lower energy use Design & Construction Use less (i.e., stronger) material Create longerlasting designs Use Buildings: lower energy consumption Pavements: lower fuel consumption End-of-Life Enable material recovery This may require trade-offs with burdens of other life cycle phases Slide 16

17 Life cycle considerations for buildings Life cycle assessment Environmental Impact Factors in decisions Cost Life cycle cost analysis Performance (Building design process) Slide 17

18 Life cycle data should support decisions Two homes: -Same location -Same appearance -Different design & construction Which is preferred from a life cycle perspective? Home Characteristics A B Initial Cost $200,000 $250,000 Energy Performance Poor High Hazard Resistance Poor High Life Cycle Cost & Environmental Impact?? Quantitative data is not available Slide 18

19 Hub Approach: Incorporate quantitative hazard resistance into life cycle calculations Life Cycle Total Construction Use Repair due to Typical Wear and Tear Repair due to Hazard Damage Hub Research Areas Improve scientific basis for models: Thermal mass and hazard resistance models Incorporate uncertainty into analyses Develop streamlined models Integrate LCA & LCCA into design process Enabled by streamlined tools Combines probability of hazard with damage from hazard Credibility Practicality Slide 19

20 Cost (x 1,000) Life cycle cost and impact quantities can justify higher initial costs $300 Baseline Design Advanced Design Calculate: $200 Net life cycle cost and environmental benefits $100 Payback periods for entire building $0 Initial Cost Life Cycle Cost These types of analyses have been done, but the chasm exists Need more carrots Slide 20

21 Making life cycle thinking a higher priority requires a collaborative effort Changing paradigms involves technical, management, and social issues Sticks: Regulations Codes Contracts Carrots: Incentives Standards Social pressure Simple tools Slide 21

22 Thank you Jeremy Gregory Slide 22