Sustainability
By Kenton Shepard
The term "sustainability" can be used in a large number of areas. Generally, it's the encouragement of decisions about practices, products and materials which will sustain or improve the long-term health of our environment and economy.
Environmental- Environmental sustainability refers to the continuation at present or increased levels of those aspects of the environment necessary for human life and well-being. This includes maintaining healthy global, regional and local ecosystems and protection of the air, land and seas from pollution.
Economic- Economic sustainability and sustainable development are basically two different names for the same idea. To be healthy, an econcmy must grow. Sustainable growth means making economic decisions which take into consideration environmental issues which will impact our economy.
Laws regulating the fishing and lumber industries are examples of how environmental and economic sustainability are connected. Over-harvesting of each must be prevented to avoid damaging the economic health of that industry and the physical environment which supports it.
MEASURING ENVIRONMENTAL IMPACT
One way to measure the environmental impact of a home is by the amount of carbon dioxide (CO2) its operation puts into the air.
The average home is responsible for putting approximately 40,000 pounds of CO2 into the air each year, most of which is produced by power plants supplying homes with electricity, oil or gas.
Opposite a home using conventional energy sources is a tightly-built home with a photovoltaic system which produces not only its own electricity for the year, but a small surplus. Homes whose operation produces no CO2 are called "carbon-zero" homes.In addition to money saved on utility bills for a carbon-zero home, the environmental savings are the reduction in the amount of CO2 which would otherwise have been produced by a conventional utility power plant in producing power for that home for the year.
STRATEGIES FOR SUSTAINABILITY
Reaching environmental and economic sustainability- one might almost call it "balance" or "equilibrium" among consumption, production and maintenance- will be easier if we can develop strategies. Two common strategies for working to acheive a zero carbon-emission home are conservation and supply strategies.
Conservation Strategies- concentrate on designs or changes which will reduce the amount of energy needed. This might include installing additional insulation, air-sealing, installing energy-efficient windows, electrical fixtures and appliances, etc.
Supply Strategies- include installation of technical systems and components such as photovoltaics, solar thermal and passive solar design.
Conventional wisdom holds that conservaton strategies are less expensive but become less cost effective as cabon emission levels are reduced.
LIFE-CYCLE ACCESSMENT
Life cycle accessment is the accessment of the environmental impact or financial cost of a home throughout its lifespan. Depending on what systems are installed, "green" homes typically have a higher initial cost than a more conventional home, but the cost over their lifespan will be lower.
APPROACHES to SUSTAINABILITY
1. ENVIRONMENTALLY SAFE MATERIALS
These are materials or products whose production or use poses little or no threat to the environment and which represents no health hazard to humans.
Volatile Organic Compounds (VOC’s) are toxic chemicals found in many commonly-used products including paints, solvents, cleaners, building products such as carpet, particle board, insulation and many, many more.
As awareness of this problem has grown, low-VOC materials and products have become increasingly available. To be advertised as “low-VOC” materials and products must meet certification standards established one of a number of certifying organizations.
2. LOW EMBODIED ENERGY
Embodied energy is the term used to describe the total amount of energy contained in a material or product. The embodied energy of a material is the energy required to…
- extract and process the raw materials.
- manufacture and package a product.
- distribute a product to wholesale and retail outlets.
- deliver a product to the jobsite.
For example: the walls of a home built from logs cut on the building site would have lower embodied energy than wall assemblies built from products requiring a number of manufacturing processes and transportation, such as milled lumber, fiberglass insulation, drywall products and manufactured siding.
Source
A chart showing the embodied energy of commonly-used building materials
3. SUSTAINABLE GROWTH AND MANUFACTURING
This approach addresses resources, products and materials which can be produced more quickly than they are consumed in an environmentally and economically sound manner.
For example: trees are now grown on plantations using forestry methods designed to supply lumber on a controlled, renewable basis.
4. SUSTAINABLE PRACTICES are practices which encourage the use of environmentally and economically sound methods, resources, materials and products.
Sources for More Information
Sustainability
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