How Solar Works

"Solar Power" refers to useful energy derived directly from sunlight. When most people consider solar power, they think of photovoltaic panels that are used to generate electricity. Other ways to harness solar energy also exist, and some are even more practical or efficient than solar PV — particularly solar thermal and passive solar applications.

By virtue of sunlight's wide geographical distribution, solar power is one of the few energy sources that is relatively easy to generate on any scale from utility grade down to personal residence or even for handheld devices such as calculators or cell phones.

Type of solar strategies:

Solar photovoltaic is the only direct sunlight-to-electricity technology available. It is also the most portable and can be deployed at almost any scale. Basically, solar PV modules and panels are composed of cells with special semiconductors in them that release electrons when light hits them. The free electrons are then induced to flow, creating an electrical current. To create a solar PV system, multiple cells are wired together to create modules, and then multiple modules are wired together to create an array with a specified capacity for generating electrical power.

Solar thermal is one of the most efficient and least expensive technologies, but isn't widely deployed. The concept of solar thermal is to convert sunlight directly to heat energy through the use of collector plates. Basic solar thermal techniques are commonly used in solar water heating systems, but more advanced techniques, such as focusing or reflecting sunlight, are increasingly applied to large-scale solar thermal power plants to create steam that drives traditional turbines and generators.

Passive solar uses good design and thermal materials to reduce energy needs for a building without relying on any active mechanical systems. Through appropriate siting, windows, insulation, thermal mass, and other techniques, passive solar design works with the local climate and geography to collect and distribute heat in cool seasons and block heat in warm seasons.

Distributed solar refers to the scale of solar application rather than to a specific technology. Most electricity is generated at large central generating facilities located some distance from consumers. Solar and some other forms of renewable energy, however, can also be generated close to communities, individual homes and businesses, or directly to electric cars, streetlights or devices. This "distributed" generation reduces transmission loss and bottlenecks along power lines and also decreases risk of blackouts. An increasing number of states either require or provide incentives for distributed renewable energy generation.