SOLAR ELECTRIC SYSTEMS

Solar electric systems use sunshine to make electricity for your home or office. There are different kinds of solar electric systems. NW Mechanical solar electric systems are designed to maximize the solar potential in your region and with an existing utility connection, offering our customers an efficient and effective way to cut their payments to the electric utility company that is designed specifically for the conditions you have available. Additionally, you receive the high quality customer service of NW Mechanical.

WHY USE SOLAR?

There are many reasons to use a solar, and particularly a solar electric system, in the Pacific Northwest. Solar electric systems pay dividends through state and utility incentives and Federal energy tax credits. Solar also improves the quality of the air we breathe by reducing greenhouse gas emissions while generating energy without pollution. Solar electric systems installed by Northwest Mechanical are reliable, quiet, sharp looking, and designed to last. Furthermore, having a solar electric system on your house can increase the value of your home and even increase resale value.

We also can install a system that has a battery backup, which provides you with energy independence and security from power interruptions. Today’s market offers great options for battery backup.

WHERE DOES THE POWER GO?

So where does the power go that your solar electric system produces? You continue to use your electricity as you always have and can basically be unaware of the solar system. Your solar generated power is connected to a breaker in your main electrical service panel. Your solar system and the utility’s system (a.k.a. “the grid”) coordinate to provide you the electricity you need. Whether the exact electrons come from your solar system or the grid, it all acts exactly the same for you in the house as it always has. The only difference is your lower electric utility bill!

SOLAR ON CLOUDY DAYS, IN RAINY SEATTLE?

PV systems can produce electricity on cloudy days, it may not be as much as on a sunny day, but that depends on the conditions. Solar electric panels work most efficiently at around 70 degrees Fahrenheit so living in a warmer area does not necessarily mean you live in an area better for solar electric systems. Seattle receives about 70% of the annual solar potential that the Los Angeles, California area receives! So there is great solar potential in the entire Pacific Northwest region.

BASICS OF SOLAR ELECTRIC SYSTEMS

PV systems convert sunlight to electricity reliably and pollution-free.

In a nutshell, the solar electric systems designed, installed and serviced by NW Mechanical use photovoltaic (PV) solar modules, or panels, to harness the sun and generate electricity. The solar modules make what is called direct current, or DC, electricity. This electricity is fed to an inverter that changes the power from DC to AC (alternating current, the type of power most U.S. homes use). The AC power is fed to a breaker in the existing breaker box in your house. The power you generate and the power you use are monitored by meters, just like your current electricity use is monitored. When you generate more power than you use, you get credit and your meter spins backwards!

The sections below outline these different parts in more detail.

SOLAR CELL
The basic building block of a PV system is the “solar cell.”

The solar cells in NW Mechanical systems are black, round or rectangular, and consist of silicon semiconductor materials. When the solar cells absorb sunlight, the photons knock electrons loose from their atoms. These free electrons then travel in to a circuit built in to the solar cell and form a direct current (DC) electrical current. (Most U.S. households use AC, or alternating current, power; see “inverter” description on how a solar electric system changes the DC power to AC power that we can use in our homes.)

MODULE
Multiple solar cells are mounted inside of a “module”, or some times called a “panel”. Solar cells are connected together to add their power together. NW Mechanical uses modules that have a metal frame and are covered with glass.

ARRAY
PV modules can be connected together to add their power together and arrive at a power level useful to a house system. When PV modules are connected together they are called an “array.”

INVERTER
Since a solar electric system produces DC (direct current) electricity and most U.S. homes use AC (alternating current) electricity, our solar electric systems must include an “inverter”, or a machine that changes (a.k.a. inverts) the current from DC to AC. Today’s inverters are very efficient, quiet, sleek looking, and reliable. This is the most complicated part of a solar electric system. Now inverters often include much data on the system’s input and output, the utility grid’s status (e.g. working, not working, low, interrupted), and the ongoing tracking of the system’s status. Some inverters can even be connected to computers for tracking the data.

Inverters also manage the electrical flow in the case of a power outage. With this management, inverters take care of any concern of utility staff working on the power lines and being harmed by a solar system that is working even when the power grid is not; there is no danger of power being sent from your home to the utility grid when there is a power outage.

METER
The electric utility connected to the house tracks the power sent to the house from the utility power grid (or just “grid”) via a meter. Your meter tracks how much power you use and how much power you generate. Your utility bill will reflect the difference. If your solar electric system generates more power than you use, you get credit from your utility and your meter spins backwards (either literally if you have a dial meter or figuratively by your meter tracking your use and deducting the excess power you generated).

SYSTEM SIZE
PV systems can be designed to meet any electrical requirement, no matter how large or small. Systems can be intended to meet all electrical usage in a home, or simply offset part of the usage and bill of a home. How much of your house a system will offset depends on how much you use, how much you are willing to conserve, and what access to the sunlight your site has.

RESOURCES FOR MORE INFORMATION
If you would like to learn more details about solar domestic hot water systems, including other types of panels and configurations of systems and educational opportunities, there are many resources. We have listed a few here.
Home Power Magazine, homepower.com
Department of Energy, www.energy.gov/energysources/solar.htm
Solar Energy International, www.solarenergy.org
American Solar Energy Society, ases.org/index.htm
Solar Washington, www.solarwashington.org
Shoreline Solar Project, www.shorelinesolar.org