Grid Tied Solar Electricity (PV) for Homes
Grid-tied solar electricity allows you to generate your own electricity whenever the sun is out. You can either use the power as it's created, or export it to the grid and earn credits. When the rate of electricity goes up, your solar array increases in value proportionally.
- Pay less for power than you do now
- Offset C02 emissions by reducing need for coal, oil, and nuclear power
- Reliable, renewable energy system lasts 30+ years
Save Money and the Environment
More than 60% of the electricity generated in New England comes from natural gas and oil, followed by nuclear (14%) and coal (9%). Maine and New Hampshire emit over 10,000,000 metric tons of C02 emissions annually, a result of burning over 50,000,000 gallons of oil and 2,800,000,000 lbs. of coal.
Solar photovoltaic panels, in contrast, generate clean solar electricity whenever the sun shines (which is more than you expect in Maine and New Hampshire!). The technology for these panels is mature and reliable, resulting in systems that are expected to work for 40-50 years even in the Northeast's tough climate.
Solar electricity is local electricity, meaning that power is generated where it is used and does not have to travel great distances over transmission lines. This is a more efficient use of electricity that reduces strain on the electric grid. When your photovoltaic system generates more power than you are using, it helps power your neighbors' homes!
How Does Grid-Tied Work?
Grid-tied photovoltaic arrays have no batteries, no complex wiring, no moving parts - unlike the off-grid solar systems of the old days.
The beauty of a grid-tied system is that instead of buying batteries, you use the electric grid as a big battery - when you produce more than you need, you push power out to the grid. When you need more electricity than you are generating, you simply draw power off the electrical grid as usual.
The key piece of equipment is the solar electric inverter which converts the Direct Current (DC) electricity generated by the photovoltaic panels into grid-compliant Alternating Current (AC) electricity used in your home.
Whenever you are producing more electricity than you need, the extra current flows out to the grid and you get a credit from the utility which you can use against future electric bills. Homes that generate as much electricity as they consume throughout the year are called "net zero". The record low cost of solar panels combined with improvements in energy efficiency and building design has resulted in cost-effective solar electric space heating in Maine and New Hampshire.
ReVision Energy provides licensed and professional design and installation of Grid-tied PV systems and offers free quotes.
Why Invest in Solar?
Solar energy is one of the safest investment options on the market today, delivering:
- 100% guaranteed financial return on investment (you get all of your money back, then an 'annuity' for decades in the form of avoided electricity costs)
- Environmental return on investment (eliminate thousands of pounds of CO2 emissions annually)
- Home equity return on investment (solar is proven to increase the value of any property by lowering cost of ownership)
- Community return on investment (everyone benefits from cleaner air & reduced dependence on fossil energy)
Aren't These Systems Expensive?
Solar electric systems have dropped in price by more than 50% in the last few years. With generous state and federal incentives still available, and record low prices on equipment, solar offers one of the only investments for your home guaranteed to pay for itself. Over the course of 20 years, a typical solar array will save you close to $12,000!
Use our solar calculator below to see what type of system might work for your home:
The biggest advantage of a solar photovoltaic system is that once you pay for it, you own a certain amount of electric generation. As the cost of electricity increases, you pay no more for the same # of kWh generated by solar. Over 20 years, a kWh of power today will rise from around .16c to around .30c!
Like looking at data? This graph (modeled on a residential 5kw system) shows the cumulative savings over time as a solar array pays for itself and then continues to operate:
This graph posits the effective rate of electricity you will pay, green is the cost of solar (amortized over 20 years), red is what you would pay the utility, year in, year out:
For someone who can take advantage of the existing incentives, the average price per kWh from a solar array is around 2/3 of what a kWh costs from the grid today, and 1/3 of what it will cost tomorrow.
What about Rebates?
A federal tax credit of 30% of system cost is available through 2016; in Maine there is a state rebate up to $2,000 and in New Hampshire there is a state rebate up to $3,750. More info here on solar rebates for homes.
Contact us for a free solar evaluation and customized project quote.
Other Frequently Asked Questions (Solar FAQ)
- Why should I install a Grid-Tied solar electric system on my house?
Grid-tied solar electricity offers a way to fix your electricity rate for as long as 50 years. The maintenance-free panels come with a 25-year warranty and the expected useful lifespan is double that. A grid-tied pv system can protect you from electricity price increases for decades. That's a feeling of energy security that is hard to duplicate. Many of our clients feel better knowing that they are producing their own electricity without any environmental harm - that they are part of the energy solution and no longer part of the problem.
- How long will an installation take?
Our typical residential solar power job takes us about 40 hours of installation time on the roof, and about 10 hours inside the house. We typically send two technicians, so most jobs are completed in 2-3 days.
- Will it pay for itself?
Yes, at today's prices a solar electric system will pay for itself in around 10 years. As the cost for grid power increases, the system pays for itself even more quickly! With multi-billion dollar grid improvement projects already in place, the one certainty is rates on grid electricity will go up.
- Should I wait for ____ technology which will decrease the cost of solar tenfold?
While we're big fans of photovoltaic technology and have seen a lot of great innovations to solar energy systems, we sincerely believe the solar industry is in a "sweet spot" of availability of government incentives and compelling prices. Yes, solar panels will cost less in the future than they do today. But unlike microprocessors, they do not drop in price exponentially. And in the meantime, while you're waiting for the price of solar to go down, you could be generating your own power! Unlike your old computers, solar panels grow more valuable in time as the cost of energy goes up.
- What are the incentives?
Incentives change periodically, we keep an update to date guide to ME, NH & MA solar rebates. You can expect a 30% federal tax credit taken when you file your yearly taxes, and some sort of state rebate that arrives as a check a few weeks after your system is installed.
- Does my roof need to face directly south?
In Maine, the ideal roof orientation is 196 degrees on the compass (known as 'solar south'), but an installation of +/- 50 degrees (155 -245) is also fine. Within this range, power output stays within seven or eight percent of maximum. Even more easterly and westerly roof installations are viable, especially on shallower roofs. For example, a 7/12 roof that is due east or due west still achieves 77% of a system's potential performance. More important than angle, generally, is shading. We don't want to see any shading on a solar roof from 9 am to 3 pm, year-round. Technological improvements such as microinverters can compensate for shading issues to some extent. The best way to know for certain if your roof is viable for solar is to contact us for a free solar evaluation.
- Will the solar array put holes in my roof, or be too heavy?
We mount solar panels on a purpose-built aluminum rail system that is fastened about every six feet by penetrations into roof rafters. On a standing seam metal roof, these attachments are made directly to the standing seams, with no roof penetrations. On asphalt roofs, each mount is sealed with 50-year silicone sealant to prevent any leaks. We have not heard of a single leak as a result of PV mountings. As for the weight of the array, it is less than 5 pounds per square foot, so a typically framed roof is more than adequate to carry the weight.
- How much roof space will I need?
Every kilowatt of solar array takes about 75 square feet. So a typical 2.88kw array (twelve panels) will take a roof area about 8' high and 30' long.
- What if my roof is not adequate?
We can also pole-mount photovoltaic panels, or ground-mount panels on a concrete base. We also now offer dual-axis solar trackers built by Vermont-based AllEarth Renewables. Click here for a system example.
- How will I know if the system is working?
Today nearly all inverters come with built-in monitoring that varies based on manufacturer. By reconciling your production with your electric bill, you can get a good idea what your household's electric load is and how much of a difference the photovoltaic system is making. We have a page with more information on data monitoring.
- How will my utility bill be different with a solar electric system?
It will be smaller! Kidding aside, the way that utilities "Net Meter" electricity can be a bit confusing the first time you receive a utility bill once your solar electric system is installed.
With solar, your inverter and your household loads are all "behind the meter," meaning that if the sun is out and you are in your house and running loads - say a TV, dryer, and electric stove - your solar-generated power will be consumed without it ever being registered by your utility meter. So at the end of the month, your electric bill will say you've exported fewer kWh to the grid than your inverter says you have generated. This is because your home consumed some solar power before it was ever sold to the utility.
Though it can be a bit confusing, you can feel good about this situation because every kWh you didn't export, is also a kWh you didn't have to buy! That's putting your photovoltaic system to work.
- Will the system be noisy?
Power inverters are relatively quiet - emitting about as much noise as a refrigerator. They are generally installed in utility rooms or basements alongside existing mechanical systems, rather than in living spaces.
- Will I see a difference in my lights or in how appliances run, like on a generator?
Solar electricity is identical to grid power, so you will never notice that the house is running on solar power. What you will see, of course, is a smaller electric bill!
- How much power will I be able to produce?
On an ideal site with no shading, each kilowatt watt of grid tied solar will produce 1,200 - 1,400 kWh/year in Maine and New Hampshire. On our free solar evaluation we will use a professional solar survey tool to assess if shade or off-axis issues will affect your system, and if needed 'derate' performance estimates accordingly. We estimates all predictions with NREL's PVWatts.
- What happens when power goes out?
When the grid power goes down, the grid-tied solar electric system goes down, too. This is to prevent any accidental back-feeding of solar electricity to the grid which might endanger line-workers. While battery-based backup options exist, they are expensive, often doubling the cost of a solar array. Due to the costs and un-eco properties of batteries, we recommend efficient generators for emergency backup.
- What panels do you recommend?
We use a variety of top, well-respect solar panel manufacturers depending on the application. Currently our 'standard' panel is a Canadian Solar 240-watt panel. We are also a premier dealer for SunPower, who manufactures the most efficient photovoltaic modules on the market. All reputable solar manufacturers offer a 25-year warranty on their panels, which are expected to live roughly twice that long.
- What inverter do you recommend?
Again, we choose among a variety of top manufacturers depending on application. Among these are SunPower, SMA Sunnyboy, Fronius, and Enphase micro inverters. All inverter companies offer at least a 10-year warranty, though the inverter is expected to last 25 years or longer.