What is solar energy?
Solar energy takes advantage of the sun’s rays to generate heat or electricity. It is an infinitely renewable resource and unique for its ability to generate energy in a quiet, clean, and consistent manner.
How do solar photovoltaic (PV) cells work?
Photovoltaic cells are made primarily from silicon and other elements like phosphorous and boron. Together, they create conductivity within the cell and activate the movement of electrons. The electrons move across the cell when activated by the sunlight’s energy into the electrical circuit hooked up to the solar panel.
How much will I really save on my utility bills from a home electric solar power system?
It depends on how much electricity you use and how much you wish to offset. If you want to reduce your monthly bill to zero, then you would need to have a system large enough to do this. It is always recommended that you reduce your bill through energy efficient appliances and reduced use first, and then you can install a smaller system.
What’s the difference between solar photovoltaic and solar hot water systems?
While both types of solar systems capture energy from the sun, solar photovoltaic systems use photovoltaic panels to produce electricity. Solar hot water, or thermal, systems capture sunlight to heat water for domestic use, to heat a swimming pool, or for a radiant heating system.
How much maintenance do solar panels require?
It is important to place panels where they will remain clear of shade and debris. Generally, every few months they should be cleaned with a damp cloth to remove dirt, leaves, etc. Also, tree branches may have to be trimmed back if they are obstructing the sunlight on the panels.
When should I seek a solar professional?
Although solar energy systems are not very complicated, it is especially worthwhile to seek the help of a professional to determine the type and size of system most suited for your needs. If you are mechanically inclined, you may decide to purchase the equipment, and with our guidance, do your own installation.
What does an inverter do?
An inverter converts the DC from the panels into AC. Most home appliances run on AC. Therefore, one would not be able to use most home appliances without an inverter. We recommend a grid-tied inverter system, which sends electricity back into the utility grid, causing your meter to turn backwards.
What is the difference between alternating current (AC) and direct current (DC)?
Alternating current has electron flow in both directions in a circuit. It is the type of electricity supplied by utility companies and the type that most home appliances operate on. AC was adopted because with its higher voltage it can be transported over long distances without losing much of its electrical energy.
Direct current flows only in one direction and it is the type of electrical current produced by solar panels and batteries. DC cannot be transported far because of its lower voltage.
Is there more than one type of PV system?
There are several types of PV systems.
The day-use (or PV direct) system
The simplest, least expensive PV system is that designed to be used only during the day. This system consists of PV panels wired directly to a DC appliance. When the sun shines on the panels, the electricity generated is used simultaneously. Day use systems have no electrical storage capacity, therefore, they do not have the added expense of batteries and they operate only when the sun is shining. Day use systems water pumps are up to 2.5 times more efficient than normal AC pumps. Day use systems are an appropriate, cost effective option for loads operated only during the daytime. For example:
•Water pumping with a storage tank
•Water heating systems
•Daytime ventilation systems
•Pool pumps
A DC system with storage batteries
If a PV system is to operate when the sun is not shining; it needs a bank of batteries to store the solar energy for nighttime use or during cloudy weather. System loads can draw power from the batteries during the day or night and during clear or cloudy weather. This system’s components include panel(s) a charge controller, storage batteries, and the DC appliances that represent the system’s loads. Because this system’s loads are only DC, this system does not require an inverter to transform the DC current from the panels into the AC current required by AC loads.
A DC system powering AC loads
Most common appliances require alternating current to operate. So PV systems designed to power such appliances need an inverter to convert the direct current from the panels to the alternating current used by these appliances. Inverters provide convenience and flexibility in a PV system, but also add complexity and cost. However, AC appliances are mass produced and offer a greater number of choices at lower cost than DC appliances.
The grid-tie system
A grid-tie system is a private photovoltaic system that is tied to and generates energy for the electricity grid. Because it generates energy for a public utility, laws obligate the utility company to give credit for electricity put into the grid. That credit can then be used at night. Therefore, grid-tie owners typically have considerably reduced monthly electricity bills. Grid-tie systems don’t require a battery bank because the grid provides energy at night. However, some grid-tie owners use a battery bank with their grid-tie system in order to have an uninterruptible power supply in case of grid blackouts.