The question “What is Solar Power” tends to mean different things depending on who’s asking. This article is going to attempt to answer the question from every perspective and level of education. Whether you want to know about the physics of the sun’s energy, interested in how this energy gets converted into useable electricity and heat, wondering whether you should get solar panels on your home or business, or are an electrician looking for whether it’s important to get solar training, we aim to answer your questions in a simple and easily understandable way.
THE PHYSICS OF THE SUN’S POWER
The sun is by far the most significant source of energy on earth, in fact, until the discovery of nuclear power, it was the only. The sun’s heat creates the different air pressures that cause the winds to blow. The energy from the sun is changed into chemical energy for plants, which in turn support animal and human life – and provide energy for our daily tasks. Even fossil fuels such as coal, oil, and natural gas, were formed as a result of decomposing plants, originally supported by the sun’s energy.
Formed 4.6 billion years ago, our sun is brighter than about 85% of stars in the Milky Way galaxy. The scale of our sun is difficult to comprehend; it is 109 times larger than earth, 93 million miles away, and it takes 8 minutes and 19 seconds for its light to reach earth. Still, enough energy hits the earth every hour to supply global energy demands for one year. The trick is harnessing it.
USING SOLAR ENERGY
We will continue to benefit from the chain of energy that goes from the sun to plants to animals and humans. However, solar energy technologies have been developed to capture the sun’s energy directly to heat our homes and supply electricity. Although this is not a new development (the photovoltaic effect was first discovered in 1839), the technology has only recently advanced to the point of providing energy at a cost and scale similar to other sources. While the actual sunlight is free, abundant and infinitely renewable, the total cost of manufacturing and installing solar energy systems is often compared to the price of paying utility rates for electricity – something known as grid-parity. There are several methods to take advantage of solar energy:
Solar Photovoltaics (PV)
Photovoltaic materials convert sunlight into electricity. These are made from semi-conductor materials that come in many sizes and shapes. The solar cell is the smallest building block of what most people think of when they solar energy and especially solar PV. These cells (only an inch or two wide) are combined to create PV modules, or panels, that add up to being several feet long and a few feet wide. Modules, in turn, can be combined and connected to form arrays, which can provide enough electricity to power a single family home, depending on how many modules are connected and how much energy the home uses.
Currently crystalline silicon PV cells are the most common photovoltaic cells. When light shines on the cell, it is absorbed, and its energy is transferred to electrons in the atoms of the semiconductor materials (crystalline silicon) of the PV cell. With this energy, the electrons become part of the electrical flow, or current, in an electrical circuit. Because of the specific “sandwich” design of solar panels, the current is driven to the end-use (lights, computers, appliances, etc…) through an electrical field, what is known as voltage.
This technology is an innovative way for harnessing solar energy. This method collects the heat, as opposed to the light, from the sun and converts it into useable energy for small residential homes. A solar thermal “collector” uses the sun’s radiant energy to heat water. Heated water is pumped via an insulated pipe to the thermal store where the heat is transferred through the pipe wall. The collector is normally fixed on the roof of a building, but installations can also be located away from buildings.
This heated water can be used as hot water for showering, laundry, dishwashing, etc… as well as space heating a home.
Concentrating Solar Power (CSP)
Concentrating solar power (CSP) technologies use mirrors to reflect and concentrate sunlight onto receivers that collect solar energy and convert it to heat. This thermal energy can then be used to produce electricity via a steam turbine or heat engine that drives a generator. Concentrating solar power offers a utility-scale renewable energy option that can help meet a large communities’ demand for electricity. CSP plants produce power by first using mirrors to focus sunlight to heat a working fluid. Ultimately, this high-temperature fluid is used to spin a turbine or power an engine that drives a generator, producing electricity.
SOLAR ON YOUR HOME
The idea of infinite free energy is hard to pass up for many homeowners. There is something undeniably appealing about having solar panels installed on your roof. They bring a sense of modernism, of independence and of environmentalism. It is always worth looking into, but there are many factors that must be taken into account before the actual purchase. Solar panels, once on your roof, do produce electricity for your home, and will pay for themselves over time. But buying solar panels can be a large upfront cost that many families don’t have. This upfront cost is cushioned by federal and state incentives that reduce the cost. Also, there is the option for entering into a power purchase agreement, essentially and lease, in which the homeowner doesn’t own the panels, but they buy the electricity from the solar company that does, this often comes out to a lower price than the average utility bill and is an attractive option for those interested in solar, but without upfront money.
Many electricians are recognizing the growing potential of learning how to be solar panel installers. They already have much of the skill-set necessary, they often just need to take 58 hours of solar energy training and pass the NABCEP Entry Level exam to get into the industry. As the industry matures however, there will be greater need to solar workers with advanced skills. This will require extensive experience, training and preparation for the NABCEP Installer Exam that is only administered twice a year.
In any case, many experts continue to expect solar to continue its exponential growth, as the price for panels falls and the industry becomes more efficient at installations and financing. The demand for these jobs is not going away and the cost of getting trained in solar panel installation often pays for itself in the first year.