Solar PV - Frequently Asked Questions
PV = Photovoltaics
How much electricity can a PV system produce?
How much roof area does Solar PV system need?
Does it have to go on my roof?
What size system do I need?
What happens if there is a power outage?
Can I run power to my whole house?
What happens when it's rainy and cloudy out?
How does net-metering work?
Will I ever have to pay another electric rate increase if I buy this system?
Is solar energy safe?
What maintenance and cleaning will my PV system require?
How much will a solar PV system cost?
Are tax incentives available?
How much electricity can a PV system produce? A 10% efficient PV system in most areas of the United States will generate about 180 kilowatt-hours per square meter. A PV system rated at 1 kilowatt will produce about 1800 kilowatt-hours a year. Most PV panels are warranted to last 20-30 years and to degrade (lose efficiency) at a rate of less than 1% per year. Under these conditions, a PV system could generate close to 36,000 kilowatt-hours of electricity over 20 years and close to 54,000 kilowatt-hours over 30 years. This means that a PV system generates more than $10,000 worth of electricity over 30 years.
Photovoltaic means "sunlight converted into a flow of electrons (electricity)." Photovoltaic devices -- or solar cells -- are like generators that work in sunlight. Each photovoltaic (PV) module is made of multiple interconnected solar cells. The cells convert solar energy into direct current electricity. Individual solar cells provide a relatively small amount of power, but electrical output can be significant when cells are connected together in a PV module. The cells, modules, and arrays (a linked collection of photovoltaic modules) can be connected in series or parallel (or typically a combination), to create a desired peak voltage output. The electricity your system can produce is dependent on many factors including the design and size of your system as well as your location. The most important variable to bear in mind when planning a photovoltaic installation is the power output. The power output will basically depend on four factors: the peak power of your panels (measured in peak-watts or Wp); light intensity; the number of hours of exposure to the sun and; the angle of exposure to the sun.
How much roof area does a PV system need?
Sol-Gen power systems take approximately 100 sq ft of surface area (collector area) per 1 kilowatt of generating capacity. Therefore, the average 4-kilowatt system would require about 400 square ft. of good, Southern exposure.
Does it have to go on my roof?
No! While roofs are usually good locations because they are high enough to be above any shading from trees (and many times they are facing South), there are many different mounting options for these PV systems...Detached structures, garages, covered patios, trellises, and ground mounts are just a few of the additional installation options.
What size system do I need?
Once we know how much power you use, we can easily do a sizing calculation to figure out how big a system you will need. Here is a very simple calculation: there are 5 Equivalent Sun Hours (ESH) in most of California; that is the annual average sun that's available. We multiply sun hours X system size to calculate kilowatt hours per day of energy production. That average 4 kilowatt system we were talking about before would produce 20 kWh's of electricity per day on an average, annual basis.
Can I run power to my whole house?
Yes! A Sol-Gen system can easily produce all the electricity you need for your home. They come in many different sizes, and we have a system that's just the right size to meet your needs. We typically go back and look at your old electric bills to see how many kilowatt-hours per month you have been using. Based on that, we can easily point to a Sol-Gen power system that meets the electric load you require.
What happens when it's rainy and cloudy out?
You only need daylight -- not sunlight -- to power your PV system. You can still generate electricity, even on a totally overcast day. Since PV technology requires sunlight to produce electricity, the bulk of your electricity production will take place in sunny conditions. Under bright overcast days, PV systems generate about 50 to 70 percent of their rated output; in dark overcast, the output is proportionately diminished to perhaps only 5 to 10 percent.
How does net-metering work?
With a grid-tied (Sol-Gen) solar electric system, you still have your line coming in from the utility, just like before. However now you also have a line out to send your extra electricity back to the utility grid.
Net-metering measures the difference between the electricity you buy from the utility and the electricity you generate with your solar electric system. When you are making more electricity than you are using (like on typical summer days), your extra electricity automatically gets metered back out (sold) to the utility grid. You receive credit for this power at the same rate they sell it to you. Net-metering allows you to use the electric utility grid like a bank account; you can put electricity into it that you don't use immediately, and you can withdraw the same amount later on at no net cost to you.
The net-metering billing system is a 12-month billing cycle. Because you make more in the summer and less in the winter, they allow you to credit your summer months into your winter months.
At no time will the utility actually write you a check. Net-metering requires the utilities to credit you for "up to the amount that you use." The idea is to get a system that just meets your needs and avoid paying any electric bills at all.
Will I ever have to pay another electric rate increase if I buy this system?
If you opt to purchase a solar electric system that covers your entire electricity usage, you won't ever have to pay for power again. Investing in a solar electric power system is like buying insurance against future rate hikes... you’ll never get another electric rate increase for the next 30 years. You become your own power company. You’ve bought the generator, now the fuel (sunshine) is free!
Is solar energy safe?
Solar panels are completely safe. Solar cells are mostly made of silicon, the primary component of sand. There is no exhaust and no toxic materials to leak out of the system. The electricity coming through the inverter is just like the electricity coming from household wall sockets. When handling it, you should use the same care you would with utility power. The glass doesn't conduct energy so you can't be hurt or electrocuted by touching them – even when they are installed and connected. The final connection and commissioning of your Solar PV system is undertaken by an accredited electrician to ensure the highest degree of safety and quality service.
What happens if there is a power outage?
Solar PV systems are grid-connected, which means that if there is a power outage, your system will automatically be switched off. This is designed as a safety measure to protect individuals who may be working on restoring the power supply from any electricity that might flow back into the grid from your system. If you have a battery back up system, the power will remain working.
What maintenance and cleaning do the systems need?
The short answer to this is absolutely none. Solar PV panels are silent, have no moving parts, and require very little to no maintenance and upkeep. They are virtually maintenance-free. For the most part, rain is a natural cleaner for the modules, however, on occasion you may have to hose them off if you have a build up of dirt that the rain doesn't take care of.
How much does a solar system cost?
The cost will obviously depend on what size system you wish to install. However, solar is actually far more economical over the long-term than buying your power from the utility. After the state rebates and tax credits, if you finance the system over its warranty period, the monthly cost of solar can run about the same as your current electric bill. The big advantage is that this cost will never increase, while the cost of electricity from the utility has increased at an average rate of 6% per year over the last 30 years. Solar is a great investment for the long-term. Sun Enerygy Systems consultants can help design a system for you that fit both your budget and your roofing requirements.
Are tax incentives available?
A Federal solar tax credit and a very generous California State Cash Rebate have made investing in Sol-Gen solar electric power system more financially attractive than ever. The California Public Utility Commission presently offers a cash rebate which covers 25-35% of the installed system cost. Additionally, there is a 30% Federal Tax Credit for all solar systems installed between January 1, 2006 and December 31, 2008. The credit is capped at $2,000 for residential applications.
The financial incentives available for solar are significant, however, the funds are limited and are available on a first-come, first-served basis. This is the perfect time to guarantee your energy security for the future by taking advantage of these generous financial incentives and locking in your reservation today.
*This table shows the savings that can be expected over the years from a 3 kW grid-tied system. As you can see, the cost-savings from a Sol-Gen™ system can be tremendous.
Mailing Address: P.O. Box 2596 * Monterey, California 93942
From Salinas Call: 424-4403
From Santa Cruz Call: 429-6655
