A little bit of history...
The Earth has been absorbing solar energy for five billion years. Humans have been using solar energy for several thousand years.

Ancient Greeks and Romans recognized and appreciated the advantages of what we now refer to as passive solar design (see below)—manipulating architecture to make use of the sun’s capacity to provide light and heat to indoor spaces. In the 6th Century AD in Rome, sunrooms in houses and public buildings were so customary that the Justinian Code initiated “sun rights” to ensure individual access to the sun. Read more on the history of solar.

What is solar energy? Solar thermal energy relates to the harnessing of light (photons) from the sun to produce heat. On a clear day, the amount of solar energy accessible at the Earth’s surface in the direction of the sun's rays is typically 1000 W/m2. Solar photovoltaic energy is another form of solar energy, which involves converting the sun's energy into electricity using photovoltaic cells (referred to as PV cells or solar cells).

How does one capture solar energy? Applications of solar energy fall into three main categories: heating/cooling, electricity production, and chemical processes. Within these categories, applications range from personal use to large scale commercial and agricultural operations.

Solar thermal technologies include passive solar systems for heating buildings and solar concentrator power systems or solar thermal power plants as they are known as, which use heat generated by the sun to produce steam, which then turns a turbine and generates electricity.

So what kind of solar would be the easiest (read: cheapest) to adopt? The most basic and least expensive photovoltaic systems are designed for day use only, consisting of modules wired directly to a DC appliance, with no storage device (e.g. battery). When the sun shines on the modules, the electricity generated is used directly and immediately by the appliance. When the sun stops shining, your appliance stops working. Increased power output requires higher insolation (sunshine) levels.

These simple systems are an appropriate, cost-effective option for loads operated only during the daytime. Some examples include:

• Remote water pumping with a storage tank.
• Operation of fans, blowers, or circulators to distribute thermal energy during the day for solar water heating systems or ventilation systems.
• Stand-alone, solar-powered appliances such as calculators, toys and other devices.

Another option for adopting solar in your home is installing a solar water heater. Advantage: solar water heaters do not pollute. By investing in one, you will be reduce the amount of carbon dioxide, nitrogen oxides, sulfur dioxide, and the other air pollution and wastes created when you burn fuel to heat your household water or use power generated by your local utility.

According to the Southface Energy Institute:

“Passive solar design remains the most economical means of employing the sun to perform useful work. For example, a three-by –five feet south-facing solar electricity panel can power three, 50-Watt incandescent light bulbs. However, the “daylight” through a window of equal area placed on the south face of a home can, during daylight hours, provide more light than three incandescent bulbs. Now consider that the solar panel would cost over $800. This is just another example that efficiency and smart design should come first in a sound energy plan.”

See the June Relocalize Newsletter for online resources to help you get started.

Feeling confident about your understanding of solar energy? Test your knowledge!

---
Solar Oven Panels, isabisa
Solar Water Pump, sissi de kroon