Tag Archives: PSE

Solar Installation: Off-Grid vs. Grid-Tied

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Thinking of installing solar? How will you employ the usage of the sun’s power?

Will your system be closed loop Off-Grid; or will it be a back & forth Grid-Tied system?

Here is a description of these two available options.

Off-Grid

Historically, solar installations were viewed as an off-grid project. If the power company’s lines didn’t drop to your property, you could use solar to make your own electricity.

If your property is remote, or you have a desire to be fully or partially autonomous, you can still capture and keep your solar energy on site. This will require batteries and storage technology. The solar panels fill the battery with power and that electricity will be available for use. Sizing of the solar system, the dynamics of power generation, and storage capacity become considerations. Professionals such as myself can help you plan for this circumstance.

Grid-Tied

This is the most popular form of solar adoption. Installations are connected to the available electrical grid. Such interconnection offers reliability and convenience. Use the solar power you are creating and/or use the grid power when needed.

Owners of grid-tied systems are recognized by local utilities as Customer Generators. Your solar installation powers your own property as well as others, via the grid’s utility lines. As a Customer Generator, you will give the grid electricity when you are producing more than you can use. Then, later in the day, or later in the year, you will be able to use that 1:1 corresponding solar credit. This benefit is considered an important Incentive, and states without the incentive experience less solar adoption by utility customers.

In WA State we have a law that protects solar properties from ever being denied a 1:1 Credit for power they send to the grid. It is known as the Solar Fairness Act and this Net Metering Law protects Customer Generators. My blog post on the 2019 Legislative session. 

Battery Back-up

If you have a grid-tied system and you would like clean, quiet power generation when the grid is out of commission, you have the option of adding batteries. Installing batteries at the same time you add the solar means that you can apply the Solar Investment Tax Credit to that cost as well. There may be a future savings depending upon how your utility bills you for electricity. In the NW, residential power delivery is most vulnerable in the Wintertime. Those are the shortest and darkest days. Therefore the battery storage must be sized aggressively enough to have the capacity needed to power the desired loads.

Demand for Solar will soon outpace WA State’s Cash Incentive offer

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Solar above Tacoma Narrows

Wanting some solar? A new WA State Incentive program was launched October 2017.

The plan was to have a four year offer, until the $110-150M was maxed out.

Yet…

July 2018 status report by WSU Energy Program shows the program is almost 75% subscribed. Seattle City Light is over 50% full, and PSE is 65%. PSE is the state’s largest electric utility.

The offer of cash paid for solar kWhs will end once capacity of your utility or the state program monetary cap is reached, whichever comes first.

The rate of solar adoption since Oct 2017 is quicker than expected.

EV Charging at your Seattle Residence in 2017

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Residential Costs to Charge

Seattle City Light’s website say it costs $0.0175 a mile to charge a standard Electric Vehicle (EV). But rates have risen recently, so I will round this up to $0.02 a mile.

120V outlets are the standard electrical outlet. EVs can plug into those and charge the batteries inside the car.

An example of potential usage:

Let’s say someone drives 20 miles in their Electric Vehicle, and then stops to plug it in and replenish the 20 miles just “burned”.
Using a factor of $0.02 cents a mile:  $0.02 x 20 miles = $0.40

How do people charge their Electric Car’s battery?

Standard 120V electrical outlets charge an electric vehicle at the slowest rate – approx. 5 miles per hour. It takes 4 hours to charge to fill the battery to replace the 20 miles lost. Convenient to charge at the house, but slow.

Dealerships sell adaptors that can pull more power out of the 120V outlet. Twice the power in half the time. Same cost per mile, just faster power delivery to charge the battery. The plug from the car to the wall outlet can effectively be locked to the car in case someone wanted to remove it.

Where to charge:

Aside from the home, there are other charging options available, such as workplace, or stops around town.

EV charging stations like the ones at Fred Meyer, Walgreens, the mall, or Neighborhood Centers, etc. are 240V AC. That is twice as much power as the 120V AC outlets. So the car can be charged twice as fast at these 240V stations.

Dealerships have 440V fast chargers. When possible, people head for these.

Charging at an Apartment Complex

Without an effective monitor it is difficult for the tenants and owners to know the actual cost of powering the tenant’s EV.

But let’s estimate you are driving 500 miles a month.
500 miles x $0.02 a mile = $10/mo.

In the future, Seattle City Light might help facilitate EV charging at apartment complexes. For now there is not much information for tenants and landowners. Tenants and Owners must customize a solution. I tried this at my Fremont apartment location and used estimates above to explain the low cost of powering the vehicle.

I kept a log of my miles, and shared with landlady. We did not arrive at a fair solution. The cost to charge was fixed at $25/month.