Sustainability is expressed as meeting present environmental, social, and economic needs without compromising these factors for future generations A practice cannot be said to be 'sustainable for X years/generations.' The use of any span of time disqualifies the activity. Sustainability is for perpetuity.
Sustainability also means greater efficiency in resource use, ultimately giving benefits to economic growth and overcoming poverty, as well as health and quality of life.
Sustainable design and sustainable development are critical factors to sustainable living. Sustainable design encompasses the development of appropriate technology, which is a staple of sustainable living practices. Sustainable development in turn is the use of these technologies in infrastructure. Sustainable architecture (see Green building) and agriculture are the most common examples of this practice.
. Windpower technology dates back many centuries. There are historical claims that wind machines which harness the power of the wind date back to the time of the ancient Egyptians. In Europe the first windmills were seen much later, probably having been introduced by the English on their return from the crusades in the middle east or possibly transferred to Southern Europe by the Muslims after their conquest of the Iberian Peninsula.
The first half of the 20th saw further development, particularly a move toward propeller type wind machines for electricity production. By the 1920's 6 million windpumps were being used in the USA alone and their manufacture and use had become commonplace on every continent.But the glory of the windpump was short-lived. With the advent of cheap fossil fuels in the 1950's and 1960's and the development of pumping technology the windpump became almost obsolete in the USA.
There are manufacturers in several developing countries now producing windpumps. The uptake of wind machines for water pumping, however, has been generally very slow even though the technology is well suited to the demand of many regions of Africa, Asia and Latin America.
Salt and sunlight can actually be used to clean water with the SODIS method.