SUSTAINABLE ENGINEERING

Transcription

1 SUSTAINABLE ENGINEERING What it is How to do it and How to measure it Benoit Cushman-Roisin ENGS-21 / ENGS-37 6 November 2009 When we see these things, don t we need to rethink engineering? Problems are all around us, on land, in water and in the air. And those are only the visible ones 1

2 Engineering has spurred and led the industrial revolution. But, in the process it has created important classes of problems, including: Human exposure to toxics in food, air, water and soil Rising demand for energy for transport, manufacturing, heating & cooling Depletion of non-renewable resources (petroleum, metals, phosphorus) Excessive demand for water for homes, agriculture, and industry Rising demand for land for housing, food production, and economic activities (production, retail, transportation) Ever increasing number and size of landfills Ecosystem damage and habitat loss due to pollutant discharges Impact on global climate and the litany goes on. 2

3 Definition of Environmental Technology (according to Bridge to a Sustainable Future, Clinton White House, April 1995) An environmental technology is a technology that - reduces human and ecological risks (better for us and nature, during production), - enhances cost effectiveness (market competitive), - improves process efficiency (more with less material and less energy), and - creates products and processes that are environmentally beneficial or benign (better for us and nature, during use and at disposal). 3

4 There is currently no accepted definition of Sustainable Engineering, but the concept may be encapsulated as follows: Engineering in context Engineering with a conscience Engineering for a finite planet and the indefinite future Engineering in context Engineers must solve problems holistically + 17 guidelines (Institute of professional Engineers of New Zealand 2004) Engineers must solve problems holistically and proactively + 8 principles (Engineers Australia 2005) Engineers must consider true life-cycle costs (Canadian Society for Civil Engineering 2006) 4

5 Engineering with a conscience Engineers should take greater responsibility for shaping the sustainable future and must commit to: ethics, international cooperation, (Shanghai Declaration on Engineering and Sustainable Development World Federation of Engineering Organizations 2004) In our every deliberation we must consider the impact of our decisions on the next seven generations from the Great Law of the Iroquois Confederacy and used as lead inspiration by the Seventh Generation Company. Engineering for a finite planet and the indefinite future (and no the other way round!) Economy Profit Ecology Planet 3E s or 3P s Equity People 5

6 Traditional Engineering: Considers the object Focuses on technical issues Solves the immediate problem (now) Considers the local context (user) Assumes others will deal with politics, ethics & societal issues Sustainable Engineering: Considers the system in which the object will be used Integrates technical and nontechnical issues Strives to solve the problem for the indefinite future (for ever) Considers the global context (planet) Acknowledges the need for engineers to interact with experts in other disciplines related to the problem Three main challenges: 1. What are the main principles of Sustainable Engineering and how can they be applied to solve the problems? 2. Where should the boundaries lie? Boundaries are critical because the wrong scale can hide critical links. Ex: switching from steel to lightweight composite in an automobile can boost fuel efficiency but break the recycling system. So, it would seem that the wider the better, but how wide? 3. How can Sustainable Engineering be taught to the next generation of engineers? Modules in existing courses? New courses? New curriculum? 6

7 The 12 Principles of Green Engineering (by Anastas & Zimmerman, Environmental Science & Technology, 1 March 2003) 1. Apply green chemistry 2. Prevent rather than treat consequences 3. Design for separation 4. Maximize mass, energy, space and time efficiency 5. Out-pulled rather than input-pushed 6. View complexity as an investment rather than a complication 7. Durability rather than obsolescence 8. Meet need without excess 9. Minimize material diversity 10. Integrate local material and energy flows 11. Design for commercial after-life 12. Renewable and readily available. A few examples of Sustainable Engineering (SE): The Navajo Bridge in Arizona: Simple bridge across Marble Canyon but fierce opposition from local native tribe and Bureau of Land Management Solution: - Talk with all entities involved before designing anything - Design with these constraints in mind: respect for land, functionality, long term, aesthetics, etc. ( The new Navajo Bridge in Grand Canyon National Park is the only crossing of the Colorado River for a stretch of 600 miles. The $15 million steel arch bridge carries traffic across Marble Canyon, 470 feet above the Colorado River. The 1929 Navajo Bridge remains a pedestrian bridge. High strength steel was used in the new bridge in order to be visually compatible with the historic pedestrian bridge and its setting. 7

8 Designing a new computer infrastructure: - Traditional engineering: Focus on performance - Sustainable Engineering: How will widespread use impact electricity demand and electronics recycling? ( Designing a new arsenic-based wood preservative: - Traditional engineering: How effective is it in my wood product? - Sustainable Engineering: How will wide use affect the construction industry? How will the chemical affect demolition waste/recycling? (Photo: Beauchemin Lumber) 8

9 - Traditional engineering: How can I make a tire that better resists sand abrasion and heat? - Sustainable Engineering: Where will all the rubber for this come from? Where will all these tires go at the end of their useful life? Some tools are already available: - Eco-Industrial Parks (EIPs) - Pollution Prevention (P2) - Design for Environment (DfE) - Life-cycle Assessment (LCA) - Leadership in Energy & Environmental Design (LEED) and more tools could be developed: - Total Cost Accounting - Sustainability Indicators (Walmart making a start! 9

10 Eco-Industrial Parks: Basic idea: Mimic nature by gathering industrial activities in one location to promote interactions and close-loop practices, like in natural ecosystems. Systems thinking required! Flow resources in the integrated biosystem of Montford Boys Town in Suva, Fiji Pollution Prevention: Basic idea: Avoid waste pollution in the first place, as much as possible 3P at 3M Pollution Prevention Pays, since

11 Example from 3M: The manufacture of Scotch tape primer adhesive plastic film primer backing 4 layers, each using a solvent for its application! One of 3M s primary strategies for continuing to reduce air emissions has been the development of solventless technologies, for a variety of products including tapes. Some new processes are hot-melt technology, ultraviolet curing and caustic wash materials. Design for Environment: Basic idea: Include environmental considerations at the very beginning of the design process, together with performance, manufacturability, cost and safety. Considerations: - Less material - Less material variety - Recycled materials - Recyclable materials - Ease of disassembly - Less energy consumption - Longevity - Modularity etc. 11

12 Life-Cycle Assessment (LCA): Basic idea: Consider the entire product cycle from cradle to grave (procurement of raw materials, manufacture, distribution, use and disposal) Leadership in Energy & Environmental Design (LEED): Basic idea: Guidelines to build green buildings The Leadership in Energy and Environmental Design (LEED) Green Building Rating System is the nationally accepted benchmark for the design, construction, and operation of high performance green buildings. Rendering of new Life Sciences Center at Dartmouth College now under construction LEED gives building owners and operators the tools they need to have an immediate and measurable impact on their buildings performance. LEED promotes a whole-building approach to sustainability by recognizing performance in five key areas of human and environmental health: sustainable site development, water savings, energy efficiency, materials selection, and indoor environmental quality. LEED provides a roadmap for measuring and documenting success for every building type and phase of a building lifecycle. 12

13 Well, that was all about HOW to design and build stuff. But, WHAT should we actually build? What should be our priorities? To start answering this last question, let us consider where the biggest impacts are. A good place to start is energy consumption. Indeed, energy consumption is related to many environmental problems, some upstream (depletion of non-renewable energy sources & oil spills) and some downstream (air pollution and greenhouse gases). Energy consumption thus serves as a good proxy for overall environmental impact. A look at how we consume energy in the United States is quite telling. Two things stand out: - Heating of buildings - Road transportation. 13

14 A regenerative building? Want to know more about this? Take ENGS-44 Sustainable Design A zero-emissions city on the desert: Madar Abu Dhabi Construction cost of city: $22 billion Completion date: 2016 Area: 2.3 square miles Population: 50,000 residents and 40,000 commuters Office space: 65 million square feet Estimated temperature: 20 degrees cooler than the surrounding desert Resources used compared with a city of similar size: 60% less water, 75% less electricity, and 98% less landfill space 14

15 A green vehicle? One answer: Fuel-cell engines with a hydrogen economy ( Want to know more about this? Take ENGS-171 Industrial Ecology Measuring the environmental impacts of your designs: A basic life-cycle approach 15

16 Charts of Okala millipoints An application example of the Okala method: Button vs. Zipper? 16

17 So, which one is better for the environment? A closing thought: Engineering is not just an activity, it is a profession. A profession rises above an occupational specialty by including both - the cultivation of specialized knowledge, and - the use of that knowledge toward the Common Good. Reminder: Thayer School exists to prepare the most capable and faithful for the most responsible positions and the most difficult service. Sylvanus Thayer (Daniel R. Lynch, 2006) 17