PV Guide

Member interest in solar energy (PV) installations continues to increase year after year.  During the past three years, United has experienced a substantial uptick in residential solar system installations.  About 68 percent of new solar installs have occurred  during that period, and with this sudden spark of interest, United’s energy experts have been fielding more questions dealing with residential solar generation.

How Solar Works
In order to understand the opportunities afforded through solar generation, consumers should first understand how a solar photovoltaic system (PV) works. Every system design  is composed of three basic components—racking, PV modules (otherwise known as panels), and inverters.  

To achieve optimal sun exposure, PV modules should be installed on a roof or on the ground.  Roof mounts are the most common and the least expensive option, but this option does not work for everyone due to shading and orientation issues.  When designing a PV system, a southern orientation is ideal, while northern is not acceptable.  

There are many different manufacturers and types of solar panels, and some are more efficient than others. Consumers should compare power output or wattage when comparing solar panel options.  Regardless of the type of panel, they all harness energy from the sun and convert this power into direct current (DC).  

Next, the inverter converts the DC power into Alternating Current (AC), which is compatible with the home’s electrical system as well as the electrical grid.  There are two types of inverters, micro inverters and central inverters.  A system with micro inverters will have a separate inverter for each panel, while a system with a central inverter will have one inverter for a series of panels.  Both serve the same function—converting DC power to AC power in preparation to deliver energy inside the home.    

After the AC power leaves the inverter or inverters, it travels through an AC disconnect switch (required by the cooperative), then into the home’s main power distribution panel/main breaker panel.

One fundamental fact members should understand  is  that the energy production takes place on their side of the meter.  Any power generated from the solar system first enters the member’s main breaker panel and energizes any device that is on and requiring power inside the home. This decreases the amount of power that is delivered to the member from the cooperative and utility grid.  Depending on the size of the system, there may even be times when the solar panels are producing excess power, taking care of 100 percent of the member’s power needs and sending the excess power back to the grid.  

Understanding Net Metering
Net metering is a rate structure that is used to compensate members who install solar or other distributed generation resources. Not all utilities offer net metering, but United does for residential accounts with solar arrays 50 kW or below.  For members that invest in solar, net metering is an important component in making  the investment economical.  

Once the system is installed, a representative from United will meet with the member to perform a field verification, which consists of verifying the system size, labels and disconnect switches; performing a simulated outage to make sure the system properly shuts down and does not send power back on to United’s distribution system; and changing out the standard meter to a more advanced meter that has multiple registers. Once the field verification is completed and the meter has been changed, United energy advisors will meet with the member to discuss how the monthly billing works and answer any questions the member may have.

The meter used for net metering has multiple registers that keep track of the bidirectional flow of energy. When the member’s consumption of energy is greater than energy generated by the solar system, energy will flow from United’s grid to the member and appear on the delivered (DL) register.

When solar generation is greater than the member’s consumption level, excess energy will flow from the member to United’s grid. This excess energy is tracked on the received register (RC). Finally, a third net register calculates the difference between the delivered and received register. United bills these accounts on the net metering rate, or the difference between the delivered and received registers.

As an example, if  the cooperative delivers 1000 kWhs to a member during the monthly billing period, and the cooperative receives 100 kWhs from the member during the same billing period, then the member would pay for only 900 kWhs (net difference).  This member essentially would receive full retail credit for the 100 kWhs.  For the month of September 2019, the retail cost per kWh was 7.79 cents.

During a month where the received kWhs outweighs the delivered kWhs, meaning the member sent back more energy to the cooperative’s grid than what they received from the grid during the month, then there are two transactions that take place.  

First, the cooperative has a minimum bill of $25 on all residential accounts, which ensures  the cooperative recovers all costs associated with service delivery.  An account with solar remains interconnected to the grid and receives power when the sun is not powering the home. Consequently, a member with a solar generation connection first pays the cooperative the minimum billing amount of $25, before the cooperative purchases the excess power, or net kWhs, from the member.

The cooperative purchases the excess energy at Brazos Electric Cooperative’s current energy charge for generation, or monthly wholesale charges.  For the month of September 2019, the wholesale charges were 6.57 cents per kWh.  This compensation for the excess energy will remain as a credit on the account, in the member’s banked balance that can be used for future energy purchases.  

Such banked credit balances can be used against future energy purchases. They cannot, however, be used to pay the minimum bill. Energy credits to an account  will rollover from month to month and can accumulate if the member’s solar provides excess power each month.  For large, oversized systems, the member would continue to pay the cooperative $25 each month for the minimum bill, but the banked balance will continue to grow until the end of the calendar year.  At the end of  the calendar year, the cooperative will issue a check to the member to zero out this banked balance, and the accounting will start fresh for the coming year.  

For example, if the cooperative delivers a member 200 kWhs during the month, and the cooperative receives 300 kWhs from the member during the same month, then the cooperative would purchase the 100 excess kWhs from the member at the monthly Brazos wholesale rate.  The member would pay the cooperative for the $25 minimum bill and would receive a delivery credit on their account for the 100 kWhs.  This credit in September 2019 would have been for $6.57 (100 kWhs * .0657).

Don’t Do It Alone
United’s energy experts are here to help the membership at any stage along the way. Whether help is needed to research solar installation options, or in understanding billing after a system is installed, United’s energy advisors are here to give members the knowledge they need to make informed choices. The United team is familiar with current solar technologies within the marketplace and also can help members decipher any solar installation bids  they might receive.  

United does recommend requesting a free home energy audit to identify ways to decrease usage prior to installing solar.  Implementing some simple energy-saving measures in the home can save precious dollars when purchasing an ideally sized solar system for a residence.  

Energy saving measures in the home also tend to have a quick return on investment, so homeowners should complete them first. Call United today or click to schedule a free home energy audit.