Solar and photovoltaic panels absorb energy from the sun and use it to generate electricity or heat water for the home. Solar technology represents an eco-friendly alternative to fossil fuel-consumption, and can help you reduce your monthly utility costs as well as your impact on the environment. While many solar systems work best in high levels of sunlight, some allow users with low levels of light to enjoy the many benefits of solar power.
According to the U.S. Department of Energy, rigid silicon panels offer the best performance in low-light applications. Made from thin layers of crystallized silicon, these panels cost more than solar cells, but also offer a relatively-high efficiency level of 33 percent on average. This means that 33 percent of the energy they absorb from the sun is transformed into usable heat or electricity. To make silicon panels even more effective in low-light, install them on movable tracking mounts, which automatically angle the panels to capture the highest possible amount of sunlight as the sun moves throughout the sky each day.
Evacuated Tube Collectors
Evacuated tube collectors offer the most effective method of solar water heating in low-light or cloudy conditions according to the South Carolina Energy Office. While these collectors cost more than flat-plate collection panels, they also offer better efficiency and higher heat, even in low-light. This improved efficiency is due to the circular shape of the tubes that make up the panel. The shape of these tubes means they experience more sun exposure throughout the day than flat panels, and offer a greater total collection area. Liquid refrigerant or water within the tubes captures and stores heat energy to reduce energy loss, and vacuum technology within the panel prevents heat from escaping. To make these panels even more effective in low-light, add reflectors behind the tubes to maximize sun exposure levels.
Large-scale solar electric plants use special solar panel technologies to produce electricity for homes and businesses. Most rely on parabolic solar troughs, which feature a U-shaped collector panel that concentrates solar energy along a single horizontal line. According to the U.S. Energy Information Administration, or EIA, all plants that rely on solar troughs also use fossil fuels as a backup when light levels are low 1.
Solar dish collectors represent a more effective method of collecting solar energy in low-light conditions. According to the EIA, the shape of solar dishes allows them to concentrate solar energy to 2,000 times its actual level 1. This allows the plant to continue its reliance on solar power even when light levels are fairly low.
- solar-cell image by carsten jacobs from Fotolia.com