Considering solar? Some things to think about
Interest in renewable energy has grown by leaps and bounds over the past decade, and as your electric provider, we are committed to helping our Members evaluate affordable, reliable and safe energy options. If you are considering installing a residential solar system, we have provided some points to consider in helping you make an informed decision.
Questions About Solar?
Photovoltaics, or PVs, are solar panels you’ve seen on rooftops, backyards or in fields. As the sun shines onto a solar panel, photons from the sunlight are absorbed by the cells in the panel, which creates an electric field across the layers and causes electricity to flow. An inverter then converts the electricity generated by the solar panels, direct current (DC), into alternating current (AC), which can power your lights and appliances.
Just as homes come in all sizes, so too do solar panel systems. The system is to be sized according to use; the power produced is designed to match or offset the power consumed. The size of a solar panel array, or the number of panels, depends on the amount of electricity needed. To determine the system output, sizing must account for your annual kWh use, which may be found on your most recent bill. You can estimate solar system output by using an online calculator (PVWatts has a good one at pvwatts.nrel.gov/pvwatts.php), or by asking a reputable solar company to provide an estimate for you. You must also consider the addition of battery storage.
Please keep in mind that most systems we see are sized to simply offset monthly use and not to replace a home’s total energy usage. In such cases, members continue to receive a moderate bill from MEC. Accordingly, it is of utmost importance to compare your annual energy consumption to the annual output of the proposed system to determine if this is a worthwhile investment. Thoroughly comparing these numbers will ensure your system is not over- or undersized. Remember, prior to installation your Cooperative must approve the size of your system; typically, this is handled by the installer.
Solar panels typically perform best on south-facing roofs with a slope between 15 and 40 degrees, ideally with little or no tree cover. The age and condition of your roof is another consideration. The cost for repairs and re-roofing will be substantially greater once solar panels are installed. Remember, panels can also be rack-mounted and installed in your yard.
There are three aspects of cost: the PV panels, the inverter and overall installation, including the interconnection of your PV generator to MEC’s system. You must also factor in additional costs in your estimate, such as permit fees, loan interest if you finance, maintenance costs, homeowner’s insurance rates, and backup batteries for using energy at night or in case of a power outage. For a complete 6-kW residential PV system, installed at $2.80-$3.50 per watt by a small local installer, the total average cost can range between $16,800 and $21,000 before any federal solar rebates and other incentives, which could bring the final cost range to $13,320 and $15,540.
As a final check, make sure that installing a PV system, its maintenance, and financing doesn’t cost more than your current electric bill.
Net metering allows MEC Members to interconnect approved renewable generation systems to their home’s electrical system and to generate all, or some portion, of their own electricity. The output of the renewable generation system offsets the electricity that would have been delivered by MEC. Members are billed each month and charged for electricity used and credited for the excess they generate. We often describe our Net Metering program as a “virtual battery” with excess energy being “banked” for later use.
It is also important to remember that the system is sized for your annual use, and it may take several months to build a banked credit that significantly reduces your bill. If your system seems to be under producing, contact your installer to ensure everything is working properly. Unfortunately, most often it takes users a few months to discover their PV system was undersized. Keep in mind, setting a few minutes aside each month to review your PV system output will ensure it is generating at peak performance and you’re receiving the optimum energy credit. You’ll also want to compare your system’s actual annual output to any provider guarantee to ensure you’re getting what you paid for.
Selling electricity is not the primary objective of the Net Energy Metering program. PV systems are sized to meet a home’s annual consumption and any excess is carried over to the next month or next year to accommodate the higher use that occasionally occurs. Large amounts of excess energy are rare but MEC’s representatives will discuss buy-back options at initial account set up.
No, not by themselves. Without a battery system and a “smart inverter,” most residential arrays do not provide power during outages. Battery backup can also provide stored energy at night or even during rainy and cloudy days.
Your home will first use the energy your system produces, so this used portion will not be recorded as it is not delivered to the electric grid nor is it seen by our meter. When your panels produce more power than your home needs, at any given time, the excess is fed into our electric grid. This credited excess is what you see as Received kWh on your bill and delivered kWh is the amount of energy delivered to you from MEC. (Total Billing kWh = Delivered kWh minus Received kWh)
Do Your Research Before Hiring a Solar Installer
Finding a respected PV installer is critical. Do your research and ask questions. Check the Better Business Bureau website (bbb.org) for businesses with high ratings. Ask friends and neighbors who have solar installed about their experiences. Be wary of predatory sales tactics and inflated money-saving claims. When speaking with a PV installer, don’t be afraid to ask questions … they won’t mind.
Below are some suggested questions to ask:
- What are your credentials? How long have you been in business? How many grid-connected PV systems have you installed? Look for installers that have been in business for at least five years, and who are certified by NABCEP.
- What is the estimated total installed cost, as well as a price breakdown to include panels cost, inverter cost and installation cost? Are there other ongoing monthly costs?
- How much energy will the installed system generate? How does this compare to my annual KWh use? We encourage members to be well informed, which includes confirming any proposed system output on a calculator like PVWatts.
- How long is the warranty and what does it cover? Many manufacturers offer 25-year warranties for their PV panels, and most offer at least a 20-year warranty. Inverters usually have warranties between five and 10 years. Look for systems that are UL-listed and pre-certified.