Solar energy refers to energy from the sun. The sun has produced energy for billions of years. It is the most important source of energy for life forms. It’s the reason you’re alive. It is a renewable source of energy, unlike non-renewable sources such as fossil fuels. Solar energy technologies use the sun’s energy to light and heat homes, produce hot water, and provide electricity for all your stuff.
The main benefit of solar energy is that it produces minimal pollutants, making it one of the cleanest sources of energy. It requires low maintenance and is easy to install. The only limitation that solar energy possesses is that it cannot be used at night, and the amount of sunlight that is received on earth depends on location, time of day, time of year, and weather conditions.
A commercial solar energy system is a great way to power your business with clean, renewable, cost stable electricity. The following diagram illustrates how commercial solar works:
Here’s what it takes to turn sunlight into electricity using solar panels:
A photovoltaic (PV) system consists of one or more photovoltaic (PV) modules. One PV module consists of about 36 to 72 photovoltaic solar cells. The cells convert the light into electricity. The PV modules are connected in a series called an array. Because PV Arrays are built with individual, linked PV modules, photovoltaic systems are exceptionally modular, which provides for easy transportation and rapid installation, and enables easy expansion if power requirements increase.
PV systems that are grid-connected or “grid-tied” applications need an inverter or power conditioner to convert the direct current (DC), generated by the PV modules, into alternating current (AC) for use in your facility. Excess power generated and not used immediately is “sold” back to the utility for a credit to be used when sunlight is not available. This is called Net-Metering.
How PV (Photovoltaic) Cells Work
The photovoltaic cell is the component responsible for converting light to electricity. When sunlight strikes a photovoltaic cell, part of the light particles (photons), which contain energy, is absorbed by the cell. By the absorption of a photon a (negative) electron is knocked loose from a silicon atom, and a positive “hole” remains. The freed electron and the positive hole together are neutral.
Therefore, in order to be able to generate electricity, the electron and the hole need to be separated from each other. A photovoltaic cell has an artificial junction layer, also called the p/n layer. Now, the freed electronics cannot return to the positive charged holes. When the electric contacts on the front and rear are being connected through an external circuit, the freed electrons can only return to the positively charged holes by flowing through this external circuit, thus generating current. The electrical power that can be extracted from a photovoltaic cell is proportional to its area and to the intensity of the sunlight that hits the area, and is measured in watts (W).
The PV cells currently on the market convert an average of 12% to 19% of the sunlight that strikes them into electricity.
Having a true south orientation of 180 degrees will typically produce the most amount of energy production per year. But many systems are installed in orientations besides true south, with only a small reduction in total output. Considerations on orientation include, site conditions, site shading issues, aesthetics, panel tilt and electrical rate schedules. If you plan to be on a Time-Of-Use (TOU) rate schedule, then a westerly facing system will produce the most energy within the “Peak” time period, where you accrue energy credits at the higher Peak rates.
The number one rule is to never design or install a solar electric system that faces in any portion of the 180 degree arc of the compass that faces north. When you need it the most it won’t work. Needless to say, installing solar panels in the shade of a tree or building will also not be functional. The performance and therefore the return on investment (ROI) from a solar power system can be severely affected by shading–especially shading that occurs regularly due to an object that casts a shadow at the same time every day as the sun passes through the sky.
However, a newer technology using solar ‘microinverters’, allow solar panels to operate independently of each other. So if one module ends up in the shade, the others just keep on buzzing, resulting in much higher average system availability. That’s especially great news for commercial solar arrays with inconsistent shading profiles.
Inverters are the “brains” of the solar electric system. The inverter converts DC electricity to the AC electricity that your home uses. The inverter monitors the utility grid and controls your solar energy systems production, as well as shutting your system down during a utility black-out.
Most modern Utility-Tied (also grid-tied) inverters do not utilize batteries, and are much more efficient than the older battery type systems that were designed for off-grid homes.
All modern grid-tied inverters are UL Listed for grid connection (UL1741). Without the listing individual inverters are not able to be legally connected to your house’s electrical system, and do not qualify for any rebates.
An alternative to large, central inverters are Enphase microinverters, as mentioned above. Each small micro-inverter is attached to each individual solar panel. These microinverters allow each panel to operate independently, leading to significant improvements in energy production, and flexibility of array design, especially when shading is an issue.
More interesting thoughts on Solar Energy
Solar power can significantly reduce the electricity bills. Moreover, there are many tax incentives and rebate programs designed to spur the use of solar, and save home owners money at the same time.
Solar energy is a completely free source of energy and it is found in abundance. Though the sun is 90 million miles from the earth, it takes less than 10 minutes for light to travel from that much of distance.
Solar power is noise pollution free. It has no moving parts, and does not require any additional fuel, other than sunlight, to produce power.
Solar energy which comprises of radiant heat and light from the sun can be harnessed with some modern technology like photo-voltaic, solar heating, artificial photosynthesis, solar architecture and solar thermal electricity.
The solar technology can be distinguished into active and passive. Photovoltaic panels and solar thermal collectors which harness solar energy are examples of active solar technology. Passive technology includes constructing rooms to improve air circulation, orienting space to favorably use sunlight.
Solar powered hot water systems utilize solar energy to heat water. In certain areas, 60 to 70% of water used domestically for temperatures as high as 60 degree Celsius can be made available by solar heating.
Solar power is the most exciting use of solar energy. It is how solar energy is converted into electricity by using either photo-voltaic (direct method) or concentrated solar power (Indirect). Large beams of sunlight are focused into a small beam using mirrors or lenses in the case of concentrated solar power. Photoelectric effect is used by Photo voltaic to convert solar energy into electric energy.
Thermal storage systems can store solar energy in the form of heat by using common materials with high specific heat such as stone, earth and water. Solar energy can be stored also in molten salts.
The oil crisis of 1970 revealed the delicate nature of fossil fuels as a source of energy for the world. As such research in alternative, renewable energy technology like that of solar and wind energy gained momentum.
Solar energy is being recognized as the future of alternative energy sources as it is non polluting and helps combat the Greenhouse effect on global climate created by use of fossils fuels.