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SUSTAINABLE ENGINEERING

What it is, How to do itand How to measure it

Benoit Cushman-Roisin

ENGS-217 November 2008

Problems are all around us, on land, in water and in the air. And those are only the visible ones…

When we see these things, don’t we need to rethink engineering?

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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)

• Excessive demand for water for consumption, agriculture, industry

• Rising demand for land for housing, food production, 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.

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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 (more for less money) ,

- 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).

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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(and no the other way round!)

“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.

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 becausethe wrong scale can hide critical links.

Ex: switching from steel to lightweight composite in an automobilecan 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 generationof engineers? Modules in existing courses? New courses? New curriculum?

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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 non-technical issues

• Strives to solve the problem for the indefinite future

• Considers the global context (planet)

• Acknowledges the need for engineers to interact with experts in other disciplines related to the problem

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

(http://ww

w.fhw

a.dot.gov/eihd/navajo.htm)

Solution:

- Talk with all entities involvedbefore designing anything

- Design with these constraintsin 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 bridge and its setting.

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Designing a new computer infrastructure:

(http://www.cs.cmu.edu/pics/campus/images/servers.jpg)

- Traditional engineering:

Focus on performance

- Sustainable Engineering:

How will widespread use impact electricity demand and electronics recycling?

Designing a new arsenic-based wood preservative:

(Photo: Beauchemin Lumber)

- 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?

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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

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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 biosystemof Montford Boys’Town in Suva, Fiji

Pollution Prevention:

Basic idea: Avoid waste pollution in the first place, as much as possible

3P at 3MPollution Prevention Pays,since 1975

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Example from 3M: The manufacture of Scotch® tape

plastic filmprimer adhesive

primerbacking

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 ofthe 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.

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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 Centerat Dartmouth College

LEED provides a roadmap for measuring and documenting success for every building type and phase of a building lifecycle.

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 gives building owners and operators the tools they need to have an immediate and measurable impact on their buildings’ performance.

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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 thebiggest 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, ventilation and air conditioning of buildings

- Road transportation.

~1/3

~1/3~1/3

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A regenerative building?

Want to know more about this? Take ENGS-44 “Sustainable Design”

A “green” vehicle?

Want to know more about this? Take ENGS-171 “Industrial Ecology”

(http://www.fair-pr.com/meet-aae/grove2005/exhibition.php)

One answer: Fuel-cell engines with a hydrogen economy

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Measuring the environmental impacts of your designs:

A basic life-cycle approach

Charts of Okala millipoints

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An application example of the Okala method:

Button vs. Zipper?

So, which one is better for the environment?

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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”.

(Daniel R. Lynch, 2006)

Reminder: Thayer School exists …to prepare the most capable and faithful for the most responsible positions and the most difficult service. — Sylvanus Thayer