How does solar work?

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 Calculator is a good one), 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.

Is your home suitable for solar panels?

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.

How much does a PV system cost?

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 don’t cost more than your current electric bill.

What is net metering?

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 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 is undersized. Keep in mind, that 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.

Does the cooperative buy extra power that I generate?

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 the initial account setup.

I don’t understand how to read my electric bill.

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)

What is your goal?

If Saving Money is your primary goal, there are several things that you can do without investing in solar. According to the U.S. Department of Energy, improving your home’s energy efficiency is like adding another clean energy source to our electric power grid, while also improving the comfort of your home. Weatherstripping, caulking and sealing air leaks, adding insulation, and possibly upgrading an old, inefficient heating and cooling system are some easy ways to significantly lower your power bill.

If Renewable Energy is your primary goal, consider MEC’s renewable energy credits. For Members interested in utilizing energy from renewable resources for all their needs, MEC now offers electric service fully backed (100%) by Renewable Energy Certificates under the “Rider GT” rate. This Rider is available, on a voluntary basis, as a “companion rate” to any residential bill for the entire month’s electricity use and will be implemented for those using the program.

Remember, our Members’ needs are important to us and we are here to assist you. If you are interested in installing a PV system to replace some of the energy your cooperative provides, purchasing Renewable Energy Certificates, or saving money by improving your home’s energy efficiency, call and speak with one of our Member Services Representatives.