Continuing to use fossil fuels (non-renewable energy sources) to power our cities will create more air pollution and contribute to increased carbon emissions and fuel shortages. In contrast, sustainable energy is clean and renewable.


Radiation from the sun can produce energy to heat and cool our homes, buildings and cities. Solar energy can be collected in an ‘active’ way by placing solar panels on the roof or walls of a structure. Solar panels absorb the sun’s rays, which are then used to power parts of the building.

The sun can be used to heat and cool a house in a ‘passive’ way through thermal conductivity. In addition to thermal mass, the sun’s rays can be used to light a space during the day, minimizing the need for lights and reducing the electricity used by the building.


The earth stores an enormous amount of heat below its surface. This natural heat can be used to heat buildings by pumping water pipes through the earth in order to accumulate heat, and continue the flow through the building in order to emit the heat out into the spaces.


Bioenergy is a renewable energy that is made available from materials derived from biological sources. As a fuel, it may include: wood, wood waste, straw, manure, sugarcane, corn and many other by-products from a variety of agricultural processes.


Either falling water or fast-flowing water rotates turbines (a series of buckets, paddles or blades arrayed about the circumference of a wheel or cylinder), which drive generators, converting the turbines’ mechanical energy into electricity. Hydroelectric power is continually renewable and produces no pollution. Although water is a renewable resource, hydroelectric projects often lead to a disruption in habitats for fish and wildlife.


Wind turbines convert kinetic energy harnessed from wind into electrical power. Wind is a renewable, clean and sustainable energy resource.


Efficient energy use, or ‘energy efficiency’, is the goal of design efforts to reduce the amount of energy required to provide products and services. For example, insulating a home allows a building to use less heating and cooling energy to achieve and maintain a comfortable temperature within the home.

Reducing energy use is seen as a solution to the problem of reducing carbon emissions. According to the International Energy Agency, improved energy efficiency in buildings, industrial processes and transportation could reduce the world’s energy needs in 2050 by one third, and help control global emissions of greenhouse gases.