Increasing Your Grid-Tied Solar System's Return on Investment (ROI)

If you are not using all the power from your panels, you're losing money or

if your panels are not generating their maximum potential, then you're losing money. These are the most common cases that can cause your perfectly working grid-tied system's ROI to plummet.  No one can predict when the sun is going to shine and so many experienced users have accepted these losses as just the nature of solar. Their solution is to install more panels or more batteries to cover the losses. This actually has the opposite effect of decreasing the ROI. We believe we have found an inexpensive solution that will minimize the losses and dramatically increase the ROI of any grid-tied (hybrid included) system. Note, this does not apply to systems running totally off-grid because we haven't found a good way to measure the potential extra power or overloaded power.

By following a simple strategy, you can increase your ROI of your grid-tied system by as much as 100% or more. The strategy is to have loads that can turn on/off or adjust its power usage based on the maximum power available. In addition, a grid-tied solar system should not restrict the power generated as this does not allow the panels to output its full potential. A panel by itself will always generate as much power as it can, but a grid-tied solar system can restrict this when there is a zero-export rule. If there is exported power, your power company may pay you a minimal amount like at wholesale rates, but they will still charge you retail rates which negatively impacts your ROI. Because of this, your load should increase to use up any extra power while allowing your grid-tied solar system to generate the max power and decrease when there is not enough power. The controlled increasing and decreasing of a load's power usage is the key to increasing the ROI.

To implement this strategy, multiple loads must be coordinated based on user priority and available power. A load that can be increased or decreased based on available power is also known as a power diverter. Traditionally, a power diverter is a specific device that has a built-in way to measure the available power and control the power usage such as an electric water heater. This can be expensive especially if there is nothing wrong with your existing water heater. And what happens when the water heater has reached it's set temperature? You're now back to the original problem of having extra power. Therefore, having a single power diverter alone is not enough to implement this strategy. The solution is having multiple diverters that are not specific devices, but rather devices you are already using to minimize spending more money.

Our proposed solution is to make common loads that you already own into power diverters. In fact, as long as you can control your load via software i.e., home automation software, you can make it into a power diverter by following our open diverter protocol and using our controller/power meter called PowerMC (under $100 USD and currently only available for North American power systems). If you don't have a home automation system or not familiar enough with yours, then we also have inexpensive hardware kits that allows you to turn any EV charger or HVAC (mini-split only) or specific power supplies (as battery chargers) into power diverters.

The PowerMC measures the available power using a CT (current transformer) and "orchestrates" a network of power diverters to automatically track the power generated to export within 2% no matter what the condition of the sun is. This means each power diverters do not need have to measure the available power thus saving in cost and complexity. PowerMC has a proprietary algorithm that ensures reliable tracking for any solar system in North America. The PowerMC uses an open network technology called MQTT and can talk to any power diverter that follows our open diverter protocol.

To see PowerMC in action, we have a live feed of the energy flow of such a system on our home page (near the bottom) at 2muchsun.com. This system uses a standalone battery system and a battery grid-tied inverter along with a SolarEdge grid-tied solar inverter, PowerMC and the following loads as power diverters; fountain pump, dehumidifier, EV chargers, battery chargers, and 2 mini split HVAC systems. As you can see, this system uses less than 2% from the grid while exporting less than 2% to the grid during the highest electricity price period from 7 am to 9 pm. This system also uses energy arbitrage to charge up the batteries since the solar system is not large enough. The reported electricity savings has been about $150 USD per month.