What Is Solar Power?

Solar energy is among the cleanest forms of renewable energy on the planet. This important resource is being used across the Commonwealth.

 

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Virtually all of the earth’s energy resources, including both fossil fuels and renewables, originate from the sun. Today, solar energy not only takes the form of the more basic passive solar design, but is also applied through highly advanced, cost-effective photovoltaic cells and other solar energy technologies. Solar energy can be divided into three major categories – passive solar, solar-thermal and photovoltaic.

 

Passive Solar

Passive solar design takes advantage of a building’s structure to capture the sun’s heat, either storing or distributing it, reducing the need for conventional heating, cooling and/or lighting. Examples of passive solar design include large, south-facing windows, dark colored tile floors, stone fireplaces, brick interior walls, “sunspaces” (or greenhouses) and super-insulation. Passive solar buildings are often equipped with features, such as overhangs and ventilation systems, which keep them cool in the summer months and warm in the winter months. Commercial buildings present a different type of challenge than residential ones because of the heavy lighting and equipment use. The most crucial aspect of passive solar design for commercial buildings is the building orientation relative to the solar path. Other aspects of passive solar design, such as shade trees and indoor atriums, coupled with energy efficiency measures, can help increase the overall efficiency of a commercial building.

 

Solar-Thermal

Power plants often use fossil fuels as a heat source to boil water. The steam from the boiling water then rotates a large turbine, activating a generator that produces electricity. Solar-thermal concentrating systems use sunlight as the heat source, eliminating the need for fossil fuels. There are three types of solar-thermal concentrating systems – parabolic troughs, parabolic dishes and central receivers. Parabolic troughs, primarily used for industrial purposes, are curved reflectors that focus sunlight into a line receiver in which fluid is heated. Parabolic dishes, also used in industrial applications, are bowl-shaped reflectors that focus sunlight into a small receiver through which passes a heat-transfer fluid. Central receivers, which have traditionally dominated the U.S. Department of Energy’s solar thermal program, are sun-tracking mirrors that focus sunlight onto a large receiver.

 

Photovoltaic Cells

Photovoltaic (PV) cells, or solar cells, convert sunlight directly into electricity. As the sun strikes a PV cell, the semi-conducting materials within the cell absorb the sunlight, producing electricity. Solar cells are often used as simple systems that power small calculators and wristwatches. More complicated systems provide electricity for pumping water, powering communications equipment, lighting homes, and running appliances. A series of solar cells form a PV array or “solar panel.” Between 10 and 50 solar panels are needed to power an average household. PV panels are installed on buildings in places of maximum sun and minimal shade in order to take full advantage of the sun’s power. There is very little maintenance required to sustain solar equipment. So long as panels are kept clean, they can last approximately 20 to 30 years.

 

Solar power can be used in a grid-tied system or in a distributed system. A solar grid-tied system links a series of solar panels through a power inverter to the utility’s electric grid. The solar panels generate a direct current (DC) by drawing on energy from the sun. The inverter then converts that direct current to an alternating current (AC), which electronic devices and appliances can use. Batteries are not necessary to supplement the system and any excess electricity generated by the solar panels is redirected by the inverter back into the grid where it can be used on other premises.

 

Distributed systems work independently from a utility’s electric grid, using batteries to store the power. Similar to a grid-tied system, distributed solar panels typically use a power inverter to convert the direct current from the sun into an alternating current, to be used on location. However, some systems function without an inverter and run only DC appliances.

HBS Solar … Smart Solutions for Smart Businesses

Email george@hbsadvantage.com to learn more about solar opportunities in Nj and the Phila area