Between the lines: Got solar? Got power! Not so fast…

Cole Brodine, Manager of Engineering

Cole Brodine, Manager of Engineering

Guest column by Cole Brodine, Manager of Engineering

So, you just installed a solar renewable generation system. Now, you’ll have power all the time with no interruptions, right? Not so fast! It all depends on a device called an inverter.

The typical renewable generation system, including solar and wind, generates DC (direct current) power, like a car battery. The DC power must be turned into the standard AC (alternating current) power that is normally used in a customer’s home by an inverter. There are two types of inverters commonly available today: “off-grid” and “grid-tied.”

Off-grid inverters

Off-grid inverters are designed to work with a battery and other customer-owned generators to provide power without being connected to the power company. These inverters cannot be connected to a utility as they are designed to work with the customer’s isolated electrical system. They cause safety concerns if connected to a utility. This is one of the reasons why Dawson PPD prefers customers with generators to have a proper transfer switch or under meter disconnect. We even offer rebates for the installation of your switch.

If you install an off-grid system, you might not even have a utility line on your property.

The typical renewable generation system, including solar and wind, generates DC (direct current) power, like a car battery. The DC power must be turned into the standard AC (alternating current) power that is normally used in a customer’s home by an inverter.

Grid-tie inverters

On the other hand, grid-tie inverters are specifically designed supplement utility power, not replace it altogether. There are industry standards for these inverters which manufacturers must follow to ensure the safety of line workers, customers and their equipment. The standards ensure that an inverter detects when utility power is lost and then quickly disconnects the renewable generation. These inverters do that by closely monitoring the voltage and frequency of the power grid, then safely adjust as needed.

Grid-tie inverters are even known to be set with such slim margins from the factory that they will disconnect when there is no true outage, but just a disturbance on the line. Examples are a large motor starting somewhere on the grid that temporarily takes voltage outside of normal limits or an electrical storm in the area. In this instance, a power outage on our distribution system means your solar inverter will not work. This type of system requires you to be “tied to the grid.”

The budget-friendly choice

The vast majority of Dawson PPD’s customers who own a renewable generation system put in grid-tie systems. It just makes the most economic sense. At the end of the day, utility power is still very cost effective, as compared to batteries and fossil fuel generators that require lots of capital expense and maintenance.

Before you install a renewable generation system, like solar, make sure that you do your homework first and fully understand your investment to know if it’s the best choice for you.

 

April 2018

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