What is Solar Power?

Solar energy, the radiant light and heat from the sun, is harnessed into usable energy in the form of solar power. The most common example of capturing solar energy into operative solar power is photovoltaic solar panels. Solar power is the cleanest, most abundant renewable resource at humanity’s disposal. There are two different forms of solar: active and passive. Before diving into the key differences, this video goes into detail about how solar panels actually work and how important they are to a sustainable future.


Active Solar

Active solar uses mechanical or electrical devices to control a solar system. An example of active solar would be photovoltaics. Photovoltaics, or PVs for short, gets its name from the actual conversion it performs to create energy. It commonly made from silicon. PVs can vary in size from local residential solar panels to a vast solar array such as the Foothills Campus Chrisman Field Solar Plant at Colorado State University.


Passive Solar

Passive solar is designed to reduce the need for mechanical cooling and heating and artificial lighting during the daytime hours. The building’s orientation to the sun factors into consideration to maximize efficiency. Instead of mechanical or electrical systems controlling the energy intake or output, the windows and walls of the home are made to intake heat during the winter and reject heat in the summer. In the winter, passive solar systems allow the sun’s UV rays into the building and trap them there, so that the heat cannot escape the building. The heat is then slowly released into the home. In the summer, the passive solar system does the opposite; heat is slowly released out of the home and only cooler air stays inside.

An example of this would be a Trombe wall:

  • A trombe wall is a thick wall painted with a heat-absorbing color with a layer of glass placed over it with a small space in-between for air.
  • Heat takes approximately 8-10 hours to reach the building, so it can heat a home long after the sun has gone down.
  • A passive solar system uses the sun’s heat as it passes through the Trombe wall.
  • This image depicts the flow of heat as it moves inside the building, while cooler air is released from the home during the winter months.

Picture from sustainabilityworkshop.autodesk.com/buildings/trombe-wall-and-attached-sunspace