Frequently Asked Questions
Beyond the fact that both receive energy from the sun, the two types of solar energy systems are completely different.
Solar hot water systems collect radiation from the sun to heat a food-grade glycol fluid inside collectors mounted on a roof. This heated fluid is circulated and exchanges heat into a holding tank. The holding tank feeds solar-heated water into your domestic hot water system.
Solar electric systems convert sunlight directly into electricity. This electrical energy is then converted to be compatible with your utility service. It is then interconnected to your existing electrical system to reduce the amount of electricity that you need to purchase from your utility.
Yes, according to a recent study at the Florida Solar Energy Center at the University of Central Florida. They analyzed solar power capability throughout the United States. The result, this map shows that the Southwest is the optimal location, but Florida and Eastern Massachusetts are right there with 88% of the solar capacity of central Arizona! If it is hard to believe, consider this fact: modern solar technology is more efficient when it is kept cool. Our cool climate and summer sea breezes actually make electricity production soar!
A grid-tied electrical system produces alternating current (AC) which is fully compatible with the electricity supplied by the power company. So at times, when your electrical needs surpass your system’s production, the additional electricity flows to you from the grid and your meter counts forward as normal. However, when your system produces more than your electrical needs, you supply power back to the grid and your meter counts backward. At the end of the month, you only pay for the difference (net metering). This lets you produce, and get credit for, as much energy as possible without having to worry about batteries or other storage systems. It’s the clean, easy, and efficient way to generate your own power. Think of it as “What you don’t use, you automatically sell to your neighbors!”
Light is energy. Electricity is energy. A photovoltaic cell converts the energy from light (photo) to electrical (volt) in one step. The way the cells do this trick is complicated and it depends on the type of cell technology. But it can be thought of this way: as light is absorbed by the cell, a light wave kicks an electron up an electrical hill. This electron now has more energy since it can drop back down the hill later. A solar panel is made from many such cells, each of which has many electrons that have been kicked up the hill. These cells are all connected together and it adds up to a lot of electrons ready and waiting to fall back down that hill. So the photovoltaic panel is kind of like a big battery, with one side having electricity wanting to get to the other side. So there’s the power, but how is it changed from “a big battery thing” to the kind of electricity you can use to power a house? That’s the job of a gadget called an inverter.
A photovoltaic panel converts the light energy to electrical direct current (DC) energy, but the electrical power in your house is alternating current (AC). The inverter gets its name for the way it takes a direct flow of electricity and flips it up-side-down then back up-right. It does this in a nice smooth wave exactly 60 times every second. It’s the electrical equivalent of converting a river flow of water into waves; rivers and waves both have energy, just a different way of delivering it. Modern inverters are very sophisticated devices. They typically have 95% or better efficiency, they can report how much power they are converting, and they are reliable and maintenance free. My Generation Energy uses micro-inverter technology, where each panel has a dedicated inverter. This delivers optimal performance of the entire system and provides pinpoint reporting of electricity production.
Fortunately, with net metering, it is not necessary to size the system precisely for your usage requirements. But it’s still worth thinking about the size that will reduce your annual electrical bill to zero. Start with your electric bill. Most of us just look at the “amount due” line and sigh, but the statement is packed with useful information. The bar graph that’s on most electric bills is a good guide. If you use air conditioning, then the summer months will probably be the tallest bars, the most kWh you used. (The good news: this is also when your system’s solar power output will be the highest!) To size the system for the summer months, take the height of the bar (in kWh) and divide by 180 hours. The answer will be an estimate for the largest system you might consider…unless you would like to produce more than you use. Under the new regulations in Massachusetts, this is a viable option too.
For example, if your electric bill graph shows the tallest bar is about 900 kWhs in July, then take that 900 kWh and divide by 180 hr to get… 5 kW. So a 5 kW (5000 W) system will probably be a good fit for your current needs.
Sometimes, a house or small business can easily accommodate the ideal number of panels on a south-facing roof. But if not, it makes sense to install the maximum number for efficient operation and then take energy saving steps to further close the energy gap. Saving energy is always more effective than producing energy that’s later wasted!
Do you want to be the guinea pig for some new technology that might not last? Of course not. Modern solar electric systems have stood the test of time. The companies that have developed the technology for the past 40 years know what they’re talking about when they provide a 25 year warranty. The panels and new inverters carry a 25 year warranty and the installation warranty (covers parts and labor) is a full 5 years. With stainless steel and anodized aluminum hardware, waterproof electrical connectors, and professional installation, the system is designed to easily weather our New England climate. Ok, but what is not covered under the various warranties? Damage, for example a tree falls on the system, is not covered under the warranty. However, your homeowners or business insurance should cover this type of event. The panels have tempered glass, tested for hail and hurricanes. There are no moving parts, no pumps, no fans, no valves, no motors to replace or oil. The recommended maintenance: don’t do anything.
It all sounds good, but with no moving parts, how do you know it’s working properly? Our on-line monitoring service.
Indeed, these programs can come and go. However, once your system is installed, most of the incentives are received within the first year. You are locked-in. Even the longer-term incentives such as the Solar Renewable Energy Certificates (SRECs) are secure for a term of at least 10 years.
So while no one expects the programs to go away completely, it makes sense to get locked-in now.