Since solar panels are most frequently installed on roofs, there is a strong connection between the roofing and solar industry. We felt our readers should know a bit more about solar energy before making the decision to add it to a property. Let’s start by answering some of the most obvious questions about solar energy.
How does solar energy work?
The solar panels are made up of photovoltaic (PV) cells, which convert sunlight into direct current (DC) electricity throughout the day. An inverter converts the DC electricity generated by the solar panels into the alternating current (AC) electricity. The AC electricity is sent from the inverter to your electrical panel to power your lights and appliances with solar energy.
What is net metering?
This is a billing mechanism that tracks your solar energy use. It credits solar energy system owners for the electricity they add to the grid. For example, if you generate more electricity than you use during daylight hours and your property is net-metered, the meter will run backwards and provide you with a credit against the electricity you might consume at night or during times when your use exceeds your solar output. In short, you are billed for your “net” use. On average, only 20-40% of a solar energy system’s output goes into the grid.
Do solar panels work in cloudy or foggy climates?
Yes! Solar panels work fine in ambient light and will still produce significant energy in areas that are cloudy or foggy. Solar panels in foggy San Francisco produce only 1% less energy than in sunny Sacramento. In fact, Germany leads the world in solar energy right now and doesn’t have a sunny climate.
Should I go off grid or stay on the grid?
Off-grid systems are alluring because the home or business owner is not subject to the terms or policies of the local utility, nor are system owners subjected to rate increases, blackouts, or brownouts. However, going completely off grid has its disadvantages. It won’t pay for itself for many years, unless you have some incredible incentives available. A battery-based system (off grid) generally costs about 30% to 40% more than a battery-less grid-tie system, and maybe as much as 50% more, depending on the battery bank size and other components, so the cost is more prohibitive for going completely off grid.
In addition, you’ve now taken on the duties of your utility company, troubleshooting and maintaining your off-grid solar system. In addition, it is likely that your surplus energy will go to waste, when it could be used by neighbors. With an on-grid solar system, the utility is like a big, 100% efficient battery that can absorb all your surplus energy. In addition, you can lean on it as hard as you want to for as much additional electricity as you might need.
How does solar energy affect an existing roof?
If you decide to install solar panels, you want to make sure your roof is in good shape. Solar panels can last 25-30 years. That said, it's much easier to repair and update a roof before installing a solar system than having to completely remove and reinstall the system later just to replace or repair the roof. Removal of solar panels isn't difficult, but is definitely time consuming. In terms of weight, solar panels weigh about the same as a second layer of shingle roofing, so you need to make sure your roof is able to handle the extra weight. In fact, it is a good idea to bring in a professional roofer to either install a new roof or perform some maintenance on your existing roof before installation of a solar system.
Will solar panels cause my roof to leak or deteriorate?
No. Most solar panels are not mounted to the roof itself, but are attached to a railing system that has specialized hardware designed to provide a seal from moisture and otherwise diverts water to where it naturally runs. Moreover, solar panels actually act as a barrier to harsh UV rays of sun, ultimately protecting and extending roof life.
How much maintenance do solar panels require?
Because solar panels have no moving parts, they don’t require regular maintenance. The only recommendation is to hose the panels off once a year or so. Owners who don’t even want to take that step can rely on the rain to do the job for them with only a 5% loss of efficiency.
How expensive is solar power?
It isn’t. Studies show that solar panels are one of the few household purchases that will actually pay for itself. Solar panels return 2 – 4 times their cost in saved electricity bills and pay for themselves in 7 to 15 years. If you live in a state with good incentives, your payback period can be as short as 2 to 4 years.
Will I still have power if the power grid goes down?
No. When the grid goes down, it isn’t safe for your system to be pushing energy into the grid, so your system will shut down as well.
Do solar panels require a tracking system?
No. A tracking mechanism can provide some efficiency gains for the system, but the gains aren’t really enough to justify the additional expense.
Can I use solar energy to power my business?
YES! Solar energy can be blended in to almost any commercial building. It can be used in something as simple as power security lightning to generating power for the entire building.
