Solar
Solar energy is an abundant and viable source of energy that ultimately supports all life on Earth. Energy from the sun is the only new input to Earth we receive every day. Best of all, it's free, silent, and non-polluting. In just 20 days, the sun provides the equivalent amount of energy that is contained in all of our coal, oil and gas reserves combined.
We can use the sun's energy in many ways:
- As electricity, using photovoltaics (or PV)—PV panels turn light into electricity. They have no moving parts and are completely silent. The electricity is typically stored in a battery, allowing PV-powered devices to operate at night and during periods of cloudy weather.
- As heat, using solar thermal energy—this heat can be used to provide hot water in your house, heat a pool, or help heat a house or commercial building with "passive solar" energy.
- Indirectly, in the form of wind power or biomass. The sun's energy creates wind, and also fuels plants as they grow (which in turn give us energy either as food for ourselves or our livestock, or in bio-fuels such as ethanol or wood).
By collecting the sun's energy, we can power devices far from power lines and pipelines, giving ourselves a new kind of energy independence.
There are many examples of self-powered or "cordless" devices that use solar energy to be free from wires or exhaust pipes:
- Traffic signs (both warning signs, and traffic counters to provide congestion alerts)—in the past, these were powered by gasoline or diesel generators, which are noisy, polluting, and must have their tanks re-filled to keep the signs on (a costly and time-consuming process).
- Parking meters, which used to require batteries (requiring changing and creating waste as the used batteries are thrown away).
- Lighting, which now can be installed without needing to connect to a power line; e.g. SolarOne, Carmanah
- And, of course, trash compactors!