Solar Energy Explained

About Solar

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Already Know What You Want? Register for a Solar Training Course:

• Solar PV Entry Level
• Solar PV Advanced
• Solar Mastery (Both Entry Level and Advanced)
• Solar PV Technical Sales
• Solar Thermal Installer
• Solar Financing for Mid-sized Projects

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

Photovoltaic (PV) panels used to power homes and businesses are typically made from solar cells that absorb photons from the sun's rays and release electrons, or usable electricity. These solar cells are combined into modules (panels) that hold about 40 cells. A typically home will use about 10 to 20 solar panels, called an array, installed in such a way to capture the most sunlight possible. Solar electricity usually must be supplemented by traditional electrical sources to provide power when solar panels cannot meet the need, such as when weather conditions are unfavorable. However, a grid-connected solar PV system can also sell excess power back into the grid, depending on the state laws.

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 any solar PV system. 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.

The History of the Photoelectric effect

• Edmund Bequerel, a French physicist, noted first in 1839 the photoelectric effect finding that some specific materials create small amount of electric current when exposed to sun.
• Albert Einstein in 1905 described the photovoltaic effect and the nature of light, winning the Nobel prize in physics.
• In 1954, Bell Laboratories built the first photovoltaic module to examine the phenomenon since the cost of creating the system was still too high for mass consumption.
• In the 1960's, the Space industry initiated the first significant use of the photovoltaic technology in order to provide continuous power to their orbiting spacecraft. As the technology evolved through the space programs, it became more reputable, and the cost dropped.
• During the energy crisis in 1970s, photovoltaic technology evolved as a source of power for non-space applications and became familiar to the average citizen.

The Photoelectric Process

The above image demonstrates the operation of a basic photovoltaic cell, called solar cell. When light hits the surface of the solar cell, atoms knock the electrons in the semiconductor material. The electrical conductors are attached to the positive and negative side in order to create an electrical circuit, the electrons are captured in the form of an electric current, and used as electricity.

A photovoltaic module is a nothing more than a number of solar cells electrically connected to each other set in a support structure or border, creating direct-current electricity. The most common voltage for photovoltaic is the 12-volt system and the current produced depends on the amount of light hits the module.

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Solar Thermal

Solar thermal collectors use the radiant heat produced by the sun, as opposed to the radiant light. When mounted on a roof, small tubes run through the box carrying a fluid (either water or other antifreeze solution) to be heated by the sun’s radiant heat energy. These tubes are attached to an absorber plate, which is painted black to absorb as much heat as possible. As the heat builds up in the collector, it heats the fluid passing through the tubes. This heated fluid can be used to heat domestic water, swimming pools or even space heating.

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NABCEP Certification

The North American Board of Certified Energy Practitioners (NABCEP) is the most widely recognized national solar energy professional certification organization. A NABCEP certification is generally acknowledged as the "gold standard" for professional accreditation in the solar energy industry. Professionals who choose to become certified must demonstrate their competence in the field and their commitment to upholding high standards of ethical and professional practice. This gives employers and customers a degree of certainty that practitioners have voluntarily met the high standards and qualifications set by NABCEP.

Why get a NABCEP Certification?

Having a NABCEP certification is proof that installers have the extensive knowledge and qualifications to pass the exam. In other words, certified installers automatically increase their credibility and are able to differentiate themselves from their competition.

The NABCEP Certifications promote proper safety techniques and skills to ensure a high quality of service and protect the industry’s reputation. As the industry becomes more standardized, government incentive and rebate programs are beginning to rely exclusively on NABCEP Certified professionals to perform quality work. There are four main NABCEP Certifications: Entry Level, PV Installer, Solar Heating and Solar Technical Sales, but we will focus on the most popular - Entry Level and PV Installer.

First Step: Entry Level Certification

The NABCEP Entry Level Certification is the first step for individuals who want to enter the solar energy field. The certification covers a basic knowledge of photovoltaic systems, including the application, design, installation and operation of solar systems.

NABCEP developed a Job Task Analysis (JTA) for Entry Level solar workers, which covers 10 subject areas: PV Markets and Applications, Safety and Electricity Basics, Solar Energy and PV Module Fundamentals, System Components, PV System Sizing Principles, PV System Electrical and Mechanical Design and finally Performance Analysis, Maintenance and Troubleshooting.

Entry Level Exam

The PV Entry Level Exam lasts 2 hours and consists 60 multiple-choice questions. Candidates have to arrive 1-hour prior the exam with government-issued photo identification and their Candidate Eligibility Form signed by their instructor. The score results are mailed to the candidates within 4 to 6 weeks after taking the exam.

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Can I begin working with an Entry Level Certification?

Individuals that have achieved an Entry Level Certification are eligible for working in any Entry-level position within the industry. Generally, employers understand that industry experience is a requirement for being eligible for the full NABCEP PV Installer Exam and allow those with the Entry Level Certification to start working in installation positions under more experienced installer supervision.

Next: PV Installer Certification

The NABCEP PV Installer Certification is an advanced certification that indicates that the individual has a level of experience, training and knowledge to perform solar installations to the highest industry standards. In fact, the exam is only administered twice a year because of the level of commitment it takes to actually achieve this certification.

* The training is divided in 2 categories:

• Advanced training: A minimum of 40 out of the 58 hours.
• Basic training: A maximum of 18 hours out of the 58 hours.

NOTE: In order to acquire the 18 hours of basic training, candidates must:

• Obtain an OSHA 30 certification
• Pass the NABCEP Entry Level training.

Solar PV Installer Exam

PV Installer exam lasts 4 hours and consists of approximately 60 equally weighted multiple-choice questions, with 4 choices per question. The questions cover the NABCEP PV Installer Job Task Analysis, which includes Designing Systems, Managing the Project, Installing Electrical Components, Installing Mechanical Components, Completing System Installation and Conducting Maintenance and Troubleshooting Activities.

The application for the exam must be submitted electronically or postmarked at least 71 days prior to the exam date. Every applicant must keep a copy of all their document records in case they are asked to provide any of them again. The Examination Scheduling Form that have received after receiving the approval for their certification application, must be submitted electronically, mailed or faxed at least 43 days before their examination date.

Candidates must arrive 1-hour prior the exam with government-issued photo identification and the Admission Slip that have received approximately two weeks prior to the exam and which contains the scheduled date, time and location of the examination.

In a scaled scored between 0 and 90 the required score of passing the exam is 70, note that the results are not curved. After they will be completed, they will be mailed to the candidates within 6 weeks after taken the exam.

Interested in Passing the NABCEP PV Installer Exam?