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  • Writer's pictureJeff Mathias

Do I really want to to go Off-Grid?

Do I Really want to go Off-Grid with Solar!

 

About 5 years ago, when I was co-owner of Synergy Solar, I wrote a  blog like this one about, do I really want to go off-grid with solar.  Since technology for solar and particularly energy storage systems ESS, has significantly changed, I thought it was time to refresh the blog.


One of the more common questions I get when homeowners are frustrated with the continued rising prices from PG&E is: I want to go off-grid and severe my relationship with PG&E.  When I hear this, I often use the example of gas prices and driving a car.  As gas prices increase, a few may have the ability to sell their car and use mass transit, but for most of us this would not work.  We might not live near a mass transit depot, bus and train schedules might conflict with our needs, and for others it may just boil down to it is not convenient.  Going off-grid is not that different.

 

First, we need to define why we want to go off-grid, I usually hear four issues:

 

1)    PG&E costs are two high, I want to control my utility costs.

2)    PG&E caused the fires here in Sonoma County I want nothing to do with them.

3)    I am tired of having no power when the electric grid goes down.

4)    I want to lower my carbon footprint, be environmentally friendly. 

 

Before we jump straight into answering those questions, lets pack our bags with some concepts so we can pull them out when we need them.  First let’s look at 4 concepts related to off-grid.

 

1)    What components make up off-grid systems.

2)    How do we design for off grid

3)    What are the biggest challenges?

4)    Finally, is this system efficient.

 

Most off-grid systems have 4 major components for their energy storage system, ESS:

1)    Batteries – to store power.

2)    Solar to produce power when the sun is shining.

3)    Inverters that convert DC power (batteries and solar) to AC power.

4)    A generator to produce power when the sun is not shining or for heavy loads.




Designing these 4 components are like a great meal, they must be mixed just right for off-grid to work well for a homeowner.  Plenty of batteries to cover the night-time loads.  Enough solar to cover daytime loads and charge the batteries.  Enough inverter power to cover the constant power needs of the home as well as the surge loads to start up well pumps and booster pumps.  And finally, a generator with a properly sized fuel source to charge batteries when the sun doesn’t shine and as a back-up to the home when there are issues with the ESS.

 

There are some significant challenges with designs for off-grid. While these systems are becoming more user friendly, the biggest issue I often had in supporting them, was homeowners did not understand (and in many cases want to understand) how their system worked.  When everything worked well it was great, but changes and issues became problems.  Another issue is training, with children, a family gathering, guests or even the handyman’s power tools, improper use can easily drain battery reserves.  Another issue is design, if we design for the worst case, winter solstice when sun hours are at their lowest.  To meet these winter needs we would need to install a very large solar and battery system or run our generator a great deal.  Usually, off-grid system requires their own structure to house the equipment and make maintenance easy, especially during storms.  And if that doesn’t change someone’s mind about off-grid advising them that large loads like pools, hot tubs, heat pumps, electric cars, saunas, and A/C are often not cost effective for off-grid.

 

Now the above is written for folks who want to leave the grid, but off-grid does have a viable application.  This usually occurs in some of the remote areas of Cazadero, Healdsburg, and other parts of west county where PG&E does not have power lines.  To run powerlines to some properties, I have seen PG&E quotes often exceeding $80,000 and as high as $150,000.  With these initial costs to get power to the property and the on-going usage fees, off-grid can make sense, but we still need to pay attention to minimizing our energy loads.  These properties are often raw land or already running off-grid.  Often folks buying these properties have a desire to live remotely, and as such willing to “sacrifice” some creature comforts for this lifestyle or as an option be willing pay for the added costs of a higher energy footprint. 

 




Before we leave this let’s cover the inefficiencies of off-grid systems.  Since the are usually sized for winter, during the summer when solar is cranking out power, once the batteries are full and the homes consumption is covered, the excess power has nowhere to go and is curtailed (lost).  Again because of the winter sizing issue, we need more equipment, bigger batteries, more solar and other equipment not needed for grid tied systems.  The need for a generator in these types of system causes a great deal of noise and pollution.  And we often need to build structures and store fuel, not needed with those on the grid.

 

Now that these concepts have been covered, I think we can see why off-grid systems rarely meet the four questions original poised:

 

1)    PG&E costs are two high, I want to control my utility costs.

2)    After PGV&E caused the fires here in Sonoma County I want nothing to do with them.

3)    I am tired of having no power when the electric grid goes down.

4)    I want to lower my carbon footprint, be environmentally friendly. 

 

But don’t give-up, there is a solution that meets and, in most cases, exceeds these expectations.

 

1)    With PG&E costs increase more then 50% in the past 3 years, it is no wonder people are concerned what the next three years hold.  Many customers are adding solar with an ESS to significantly lower their bills.  Under PG&E’s Net Billing Tariff, we aim to off-set 75-90% of a Homeowners electric bill, significantly lowing costs and minimizing future increase.  This is accomplished by storing solar power to our ESS rather than exporting to PG&E for pennies.  In addition, we can use this power in the evenings, discharging from our ESS when PG&E rates are high.

 

2)    While grid tied solar and ESS still requires us to be connected to the utility, we can minimize our relationship with PG&E not just financially but also our dependence on their transmission lines.   At my house, while I am still connected to PG&E, my solar and ESS system allows me to be 90% autonomous from the grid.  This means I only draw 10% of my power from PG&E, instead drawing it from my ESS in the evenings.  in addition, I am only exporting about 10% of my solar to the grid with most of it being consumed by my home or used to charge my ESS.  Because of this my relationship with PG&E is significantly reduced. 

 

3)    An additional benefit with solar with an ESS is it can be configured to not only save you money when the grid is up, but also provide your home power when PG&E’s grid is down.  When the grid is down, the ESS disconnects from PG&E, and allows the ESS to provide power to the home, running the homes refrigerator, well, router, CPAP, and other needs.   For many this increased level of safety and security is the driving decision to go “off-grid”.

 

4)    Staying connected to PG&E and adding solar and ESS can be more efficient.  First equipment sizing can be designed for the average, drawing from PG&E when needed or exporting power when excess is produced, reducing resources.  Second excess solar is not curtailed (lost) but exported to help the grid.  Most grid-tied ESS systems do not require a generator, eliminating this resource, noise, pollution and need for fossil fuels.  Grid tied systems are much easier to use, often with many homeowners using a set-it and forget-it options.  Finally, the comfort and flexibility to hold large family gatherings, purchase an electric car, or heat your hot tub without the concern you will drain your energy storage system is priceless.

 

You have just joined me on an around the world trip on off-grid vs grid-tied solar systems.  As you can tell this is one of my favorite topics to discuss with homeowners over the kitchen table.  While off-grid systems do have a place, I have found they are more costly, more complicated, less reliable, and less environmentally friendly then being connected to the grid.  And for the best of both worlds, nothing beats a well-designed grid-tied solar and ESS system tied to PG&E.

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