Joe Scerbo is the owner of , a Diamond Certified commercial and residential electrician in Livermore. I wanted to find out more about solar energy, and specifically, is it "time" yet to consider putting solar panels on the roof?
There are many different forms of renewable energy including wind, solar power, solar heating, but it seems more and more that we see solar panels showing up on people's rooftops.
GENTEC is part of Shamrock Renewable Energy Group in San Ramon, a coalition of solar and renewable energy integrators that provide residential and commercial services.
What Is Solar Energy?
Solar cells or more correctly, photovoltaic (PV) cells, are silicon-based wafers that produce energy from light. By stringing many cells together into panels, and many panels together, they can produce enough electricity to power a home or a building during the daytime (when the sun is up).
PV cells have been around since their invention in 1883, but their inefficient design produced very little electricity. In 1954, Bell Laboratories invented a much more efficient type of cell, but they were relegated to toys and other low-voltage usage until someone came up with the idea of using them in large panels on satellites.
With the recent PG&E rebates and other tax incentives, Scerbo explained that it has spurred a "tipping point" where solar panel manufacturing has become more of a commodity, making it easier and cheaper for consumers to consider installing it in their home or business.
Technology continues to evolve too with new products that are more efficient, cheaper to produce and give us, the consumer, better control over the energy output.
Solar For Your Home
The first step in getting ready to consider solar is to lower your overall net energy usage as much as you can:
- Replace incandescent lights with compact flourescent bulbs (CFLs)
- Install timers or infrared sensors on lights to minimize usage when no one is in the room
- Install a seven-day thermostat to lower AC or heating requirements when you're not home
- Replace older, less efficient AC and furnace with higher rated units or a two-stage furnace
Next, take your power bills for the last three years and add up your kilowatt hours (kWh) consumed, divide by 365 then again by three to get your average daily usage. Your usage of course goes up and down depending on the seasons and days of the week, but you can get an average to guide you.
Work with an expert electrician who can then help you determine the right number of panels to install so your production is about equal to your average consumption. You don't want to overproduce, because PG&E will not cut you a check. You're also "selling" it back to them at wholesale prices, and consuming at retail prices. So it's not a one-to-one split.
With many homes, usage during the week during daylight hours may be very low because the kids are in school and you're at work. If your solar panels are producing electricity during these hours, you're putting energy back onto the grid - basically you'll have a negative consumption and your meter runs backwards.
Then during the evening, the panels aren't producing any electricity. You're pulling power back off the grid, but hopefully at a lower off-peak hours rate.
Electricians use the "sweet spot" during the 5.5 hours between 10:30 a.m. and 3 p.m. to calculate the "insolation" or how much solar radiation your panels will get, and thus how much power they'll generate.
Of course, there is power before that and after that window, so you do get more. The summer months produce more power because of the longer days and more bright sun than during the winter.
Solar For Your Business
Businesses have a different consumption model than homes, because their peak consumption is generally Monday through Friday during daylight hours when the business is open (and when power is most expensive). During the weekends, their power consumption goes down, and power production from the solar panels is all extra that gets put back on the grid.
Work with an electrician who can help you with a comprehensive energy management plan to see where you're consuming more than you should. Reduce your net usage during these peak times by using lower wattage fluorescent bulbs and fixtures, infrared sensors in bathrooms and other rooms, and install timers on parking lot lights.
It may be too that you won't get to net zero on your consumption, but if you can lower your tier 4 and tier 3 power consumption, which is more expensive, and offsetting the usage to get you into tier 1, it could have a good long-term payout.
Energy costs are going to continue to go up, so it makes sense for businesses to consider this as an option now.
What To Consider
Work with a licensed and bonded contractor who has experience in the industry. Residential experience doesn't necessarily translate into good commercial practice, so choose carefully.
Your electrical contractor should help you to put together a good plan to reduce your current usage, navigate the rebates and other tax incentives available to you, and put together good cost-benefit estimate over the life of your solar system.
Make sure they are using good quality panels that have a 20 year warranty, and at a "DB2" rating, which is recognized by the California Solar Initiative as meeting their minimum standards. Cheaper panels are available, but they won't last as long, and this reduces the payout on your investment.
Your panels have to face south to maximize the energy they collect, so there may be some considerations if your roof is pitched in an east-west direction, there's too much shade, or you don't have the physical space to accommodate all the panels you need (typically 24 for an average home).
Remember too that the panels will lose efficiency over time, at a rate of approximately 1 percent per year. So after 20 years, they may only be working at 80 percent capacity. Shading from trees and chimneys will affect their performance, and they must be cleaned a couple times per year to remove any soiling (like bird poop).
Will It Help During System-Wide Outages?
Scerbo said, "Something most people don't realize, in the event PG&E power goes down so to does your PV electrical source. PV inverters have 'anti-islanding' technology. If the grid goes down, the anti-islanding does not allow power to get pushed to the grid to protect PG&E and its workers who could be exposed to electrocution."
There's a lot to consider, and it's a large investment. Prices are coming down, but in the long run, you may be able to lower your energy consumption rate and help the planet at the same time.
Maybe now is the time to consider it.