Going Solar – Part 1

PHOTO 1: Award Winning Solar Photo by the Author (click for more information)

This is NOT about photographing the sun, at all. In particular it’s not about the upcoming total solar eclipse visible from the central to North East! This is a public service column about the good, the bad and the ugly of using solar panels and/or battery systems.

Being the engineering geek that I am, I have invested a lot of effort into researching, cost modeling and using a photo voltaic solar panels + battery system. In this column I hope to provide some thoughtful comments and insights into the benefits, and pitfalls of having such a system. Let me however give a bit of background so you understand the context.

Photo 2: Our modest (18 panel) solar system. Note the chimney shadow from late afternoon and how they avoided placing panels where they would be shaded.

Why Did I Go Solar (+Battery)?

A desire to avoid taxes. My father passed away 5 years ago and I inherited a portion of his IRA. Contributions to a 401K are tax deductible but withdrawals from such an account are taxable. I was required to take a full distribution so it was the primary impetus for my solar journey. I had been paying attention to, but not dipping my toe into solar – frankly because our electricity costs for our modest house were relatively low… that is until some brutal summers kept us indoors with massive use of an air conditioner. But the 30% Federal Tax Credit was hanging there before my eyes so by investing in a solar system from my inheritance, the taxes would be covered almost entirely AND I get an energy production system and emergency standby power during a grid outage as a side benefit. I really needed for the system to be completed by the end of 2023 for the finances to make sense otherwise I’d be paying for the system in after tax dollars. Fortunately my installer: Cinnamon Energy Systems of Los Gatos, California delivered for me! My situation is unique here since most people will be paying for a system out-of-pocket in after-tax dollars.

Chart 1: PGE Electricity Rates (cents per kWh). This does NOT include minimum monthly bill or natural gas charges or other miscellaneous charges on the utility bill. That’s a 79% increase in 5 years.

Steep, ongoing increases in electricity rates. I live on the West Coast in Pacific Gas and Electric territory. PG&E (together with Southern California Edison, and San Diego Gas and Electric) are the largest utilities in the United States. They are FOR PROFIT companies. Coincidentally PGE and SDGE have the most expensive electricity rates in the United States with one exception: rates in Hawaii are slightly higher. In 2022, for example, the national average was $0.1504 cents per kilowatt hour (kWh). My PGE charges in November, 2022 were $0.3779 / kWh – TWO AND A HALF times as much as the national average. And it’s gotten worse. From 2019 to 2024 PGE rates went up by 79% in total. And they are asking for 4% increases each of the next 3 years. In January, 2024 my rate is $0.4323 per kWh (and that’s actually a reduction from what it would have been because with solar self-production, I was able to stay in the lowest tier rather than paying $0.4728 per kWh). With the current sky rocketing rates, the system pays for itself a LOT faster than it will if energy rates were lower. Our utility bill on the current trajectory will become the single LARGEST recurring cost after health care insurance and ahead of real estate taxes! As we approach retirement, retiring the electric bill will make for a more affordable post-work period.

Being Green. This is actually the least of the reasons. I’m pro-planet, pro-environment but I also know that it will take about 2-3 years of energy production from my system to become “carbon neutral”. Carbon Neutral means that the CO2 produced during the manufacture, transportation and installation of this system will be offset by the CO2 saved. But three years is not a long payback period! An Electric Vehicle is inevitable in California… and again, even though EVs require more energy to build than conventional internal combustion engine cars, I can fill my eventual EV with 100% non-polluting FREE energy. I intend to use my EV as a big mobile battery to backup my home as well as provide transportation. Will I replace my natural gas furnace + AC system with a heat pump? Eventually, yes. Will I replace our natural gas dryer, cooktop and water heater? Eventually, yes. And when I do, most of the energy those require will come from *free* power generated on our roof and squirreled away in our batteries for those rainy days that do come.

So in short, I’m saving money for the long term, helping the planet, and enhancing the value of my home. What’s not to love?

Is Solar All They Say It Is?

There is not a single answer to this question. It depends. The POTENTIAL cost savings and clean energy benefits are clear, but does it make financial sense for everyone? Probably not. Where we live we have 4 significant factors in our favor:

  • 1. Our home has an unshaded back-of-the-house roof that faces SOUTH (the ideal direction for maximal solar power generation)
    • 2. Our climate is mild (cooler temperatures are more conducive to energy generation). Heat both reduces production and takes a toll on the materials. A mild climate also helps moderate the need for energy for heating and cooling.
      • 3. Due to our climate we have more “clear sky days” than much of the rest of the country. But its worth noting that even dreary, dismal rainy days can produce energy, too!
        • 4. Our electricity costs are extremely HIGH and increasing much faster than inflation.

Beware the Charlatans and Scam Artists.

Many solar companies are struggling due to regulatory and non-sensical billing policies established by Public Utilities Commissions – I’m not talking about those, however there are rampant problems with the Solar industry. It’s rife with charlatans, scams, and lies. I cringe every time an add pops up saying “If you live in (STATE) the state HAS to give you FREE solar panels”. Every word of that is a lie. While a “lease” or “Power purchase agreement” MIGHT make sense for some people, I would generally offer that you should avoid them. Why? Because no one is giving you free solar panels! You’ll pay for them via the long term power purchase or lease agreement and in both of those cases you actually own nothing. Those installers ARE making money because the gross cost for those arrangements will always be more than the cash cost for you to buy the system and own it. Another reason I cringe is that the lies told to lure customers in include everything from saying that the Federal Tax credit can be used to cover a re-roof (they can’t), that the Federal Tax credit is a rebate (it’s not, and not everyone will be eligible), that if you don’t lease or use a PPA that your maintenance costs will be very high (solar panels are among the most reliable components typically with 25 year manufacturer warranties, batteries and inverters are less reliable, but are more reliable than most of your appliances!).

The good news is that some solar companies are going out of business (ADT, Vivint) because they rushed in to take advantage of a “market” with a bad business structure, did a poor job or ran out of people to scam or, worse, they closed shop under one name and opened back up under a new name.

Why Local Clean Energy Production is a Great Goal.

Ultimately it’s clear that local production of energy (with local storage) is good for creating a more resilient power grid. The more energy is produced locally, the less stress there is on the grid, and the less there is a need to build costly power plants and infrastructure, the more resilient it is, and the cleaner the overall energy mix becomes. Utilities SHOULD be prioritizing cleaner, lower cost energy to move away from using polluting, limited resource fossil fuels. But of course those for-profit companies don’t share that sentiment because it undercuts their money making ability.

Why Utilities Need to Be Public and Not for Profit.

Unfortunately Pacific Gas and Electric is a poster child for what happens when a shareholder-owned, profit-driven company seeks to maximize profits. It has managed to blow up a gas pipeline destroying homes and killing 8 people, burn down at least 4 California towns killing more than 95 people in the process. In fact it’s the only utility company I know of that has been convicted of manslaughter and has filed for bankruptcy twice. Ok, got that off my chest, but it is really another inducement to produce my own energy. By the way it’s also why some communities have created public utilities for example Silicon Valley Power is Santa Clara’s not-for-profit energy source. Their rate is 0.166 / kWh. San Jose is exploring going public, as well as others. And there are options in some communities to use different power generation. For example Silicon Valley Clean Energy can provide power to residents on the San Francisco Peninsula from Mountain View down to Gilroy, but PG&E delivers that electricity and the delivery charge is MORE than the national average total charge for power.

Common Myths and Misconceptions About Solar

Chart 2: at (1) the battery ran out and energy came from the grid (2). By the end of the day (3) the battery supplied all the house energy needed up to midnight. This was also a low electricity usage day for the house.

If you have enough solar generation to cover your monthly usage, that is enough.

Untrue! Here are a few of the reasons

  1. In winter, there is less daylight (so less production), typically more cloudy weather (compare Chart 2 above, with Chart 3 below), and a lower sun-angle. You would need to design a system to generate all the energy you need in WINTER… but
  2. In summer, the longer hours of daylight and often clearer skies mean you may produce three times as much energy as you do in the winter. Unless you consume it all, you are producing “excess” energy. Extra energy is of great value, sometimes, but often not (see #6, below).
  3. Your solar system only produces energy when there is sufficient light. It doesn’t have to be direct, clear-sky sunlight, but it needs to be strong enough to generate a reasonable amount of energy. Even on overcast days our system generally produces enough energy to meet the needs of the house… though as you notice in Chart 2 sometimes it’s a struggle to do so.
  4. Most people consume energy 24 hours a day. And your daily usage no doubt is different day-to-day. For example if one day of the week you do the laundry you will use more energy on that day than most others – especially if that day also turns out to be unseasonably warm or cold requiring more heat or cooling. For example, our Christmas dinner saw us using 4 hours of oven time – the 16 kWh we used in those 4 hours just running our oven was about same amount of energy we use in a full DAY! So capacity needed varies from day to day and month to month. Oh, and most of that energy was used AFTER sunset!
  5. Producing energy is not the only criteria. For example if you want to run your Air Conditioner, it’s not enough to provide the 12 amps (2.7 kW) or so of energy you need to keep it running, you also need for your system to provide (for a time) the 60 amps of energy it takes to get that AC started! This is called peak load. Many appliances have this number printed on them even though they do not continuously use that much energy. The grid is a good source for those short-bursts of extra peak-load energy, though you CAN install enough battery peak load capacity to provide that energy. If you happen to be baking something, heating water, have a fridge in a defrost cycle all while trying to run your AC you may have to overprovision your system to meet that peak load.
  6. Unfortunately everywhere in the US (and the world) is a bit different about what happens with any extra energy you create. In some areas you can ship that excess energy to the utility company and they will pay you for it (and sell it to your neighbors at a marked up price). But what you are paid can be anywhere from equal to or MORE than what you’re charged to import energy to something as small as 1/10th of the cost of import. Indeed, some utilities will not allow you to export energy at all (or will not pay for it) because export of energy can overtax the grid! And to make matters MORE complicated, the rules are changing constantly. Any paybacks you rely on may disappear in 1 to 10 years due rate changes, additional charges, etc. “Net Energy Metering” (NEM) is different everywhere.
  7. You might NOT be able to produce enough energy to meet your peak and capacity needs! You need sufficient unshaded roof or ground space to install the needed panels. For example there is one tall tree about 100 meters (340 feet) away in the late afternoon path of the winter sun that causes our production to dip for about an hour even on clear-sky days. See the Chart 3, below, which captures a “good” winter solar production day. Also compare with Chart 2 which was a not great production day. About 4 weeks later, the sun remains higher in the sky so we don’t see a production dip at all after mid January. The takeaway on this is that your own trees, neighbors trees, power poles or other objects might put an unexpected dent in your production. Clearly the loss in this particular example is miniscule.
Chart 3: A good day of energy production
1. Importing from the grid
2. Charging the battery
3. Clear day generation.
4. Shading from a tree.
5. Battery charged now exporting to the grid
6. Running at night on batteries.

If I get solar and battery I can go off-grid and keep the power company out of my pocket.

It would be lovely if this was true. The answer to this is nuanced. Some municipalities by law require homes to be attached to the utility grid. This is generally a requirement of “habitability” (that is, a house would be considered unlivable if it didn’t have energy), but if you read through the previous misconception (it’s enough to have solar panels) you’ll see that there are plenty of times where not having the grid means your house will have to “brown out” (insufficient energy compared to demand) or black out (no energy at all). Also read above because having batteries may also not be sufficient.
And even if you CAN produce enough energy you will definitely have to change your energy usage habits significantly from what you’re probably used to (or spend a kings sum on a huge system) to go truly and completely off grid. In short, you’ll likely have a least a minimum monthly bill and as much as I’ve revealed my distaste of for profit utility companies, the truth is they are USEFUL and it costs money to maintain them and the wiring to and from your house.

Solar Panels are All I Need

What many people don’t know (I didn’t know) is if you have a solar panel system that is “grid tied” (meaning connected to your utility to back-feed that extra power that you produce as well as supply power to your house when there is insufficient solar production)… IF THE GRID GOES OUT your SOLAR SYSTEM SHUTS DOWN. It doesn’t matter if it’s noon and the sun is creating 4 times as much energy as you need. The reason is safety. If the grid goes down, a worker trying to repair a downed line could literally be electrocuted if the sun comes out and sends energy back through your house into the grid. Stated another way, if your HOUSE is producing energy, there is no way for a worker to insure safety because they can’t turn off the sun and therefore all grid attachments require electronics to automatically shut off back feeds if there is no grid power and the simplest way to do that is to make the solar system shut down completely.

Does that mean I can’t have solar if there is no grid? No. You can still have solar, but you need “islanding” capabilities. That is, your system must DISCONNECT from the utility grid and form your own “private grid” if there is no power on the utility grid. Such systems are often paired with battery systems so that a battery can supply the backup power… but it costs more to have such components.

It is also true that different systems handle shade differently. In some systems something as small as a single leaf on a solar panel can reduce the panel production by 33%. Indeed the shadow of a powerline across a panel can make a panel produce ZERO power if it happens to shade each of the separate zones in the panel.

If I Have a Battery or Battery System I Can Be Independent!

Chart 4: Using the grid for only 4% of household energy needs. Total imports were 4.4 kWh**

This is mostly true! We’ve already discussed some of the many complications of having sufficient total generation as well as enough peak power (see number 5 above).

However Chart 4 shows our electricity utilization for a week in December.
Note that “aPower” is the name of the battery system by FranklinWH.

We still needed grid power – but we only imported 4%** of our energy. The rest came from the sun directly (the yellow pie), or from the sun through the battery (the green pie). This also underscores the earlier point that almost half of our energy use was when the sun wasn’t shining, or was insufficient to meet the household energy demand.

**This graph states that we imported 4.4 kWh, but the actual number is about 7 kWh. That’s a fairly trivial difference in THIS case. Chart 4 does NOT show how much energy we exported during that week (it was significant – 47.6 kWh). In Part 2 of this article I’ll spell out why why the stated export and import amounts don’t agree with our power company and why that might matter a LOT.

Indeed there was a much worse week where we had to import almost 30% of our power because the weather was dark and bleak. By using 94% (or 70%) less electricity, we clearly have that much of a reduction on the electricity charges for our utility bill. And it’s a good thing because PG&E had not yet started processing our “Permission to Operate” so we got paid zero for the 100s of kWh we sent to the grid until it was approved.

Having a battery that has sufficient peak load isn’t sufficient to be independent. There is also a matter of capacity. We have weathered two utility power outages due to violent winds – each less than an hour for us, though it lasted in some cases DAYS for our area neighbors, and it isn’t because our battery would have seen us through the days of outage. It is because we are in a critical power area. The power lines that feed our house also feed a nearby hospital, and 4 emergency response bases (fire and police stations). Indeed two years ago we had about 4 total hours of outage over 3 days. Our across-the-street neighbors had NO power for 40 hours because they are served by different (non-critical) feeder lines!

Our current system has enough battery capacity for about 20 hours of normal load – that’s enough for us to get well into the next day for sunlight to provide energy, but as you can see from Chart 2… a bad day of production may mean the battery won’t last through a longer outage / or until the sun can provide all the household needs.

What Do I Really Want in A Solar System?

This article has already become wordy, but here are some of my recommendations. I will publish a second article on “things that go wrong“, energy hacks, and more.

But assuming you are thinking about solar for yourself, here are my recommendations.

  1. Before you consider solar, take a look at the current status of your roof, and the energy efficiency of your house. It might be wise to spend money first on resolving air leaks, insulation inefficiencies and attic and roof repairs.
  2. Take a look at your electric service (or be sure any bid you get has considered what you have). It can get pricey to upgrade electrical panels or home wiring systems to meet code requirements.
  3. Understand your tax situation if a Federal or State credit, rebate or incentive is what you’re seeking. The 30% Federal Tax credit is planned to be around for 5 years, but to get that money you have to file your taxes, AND be paying as much tax as your credit will net you. If you are on a low fixed-income you may never be able to recoup the credit by doing a purchase. This is one area where a lease (to own) may make more sense because of a quirk in the law that allows the lessor to claim the credit and pass it on to you even if you would not have a sufficient tax liability to recoup the credit yourself.
  4. Seek out bids from reputable, well established solar + battery businesses. If they haven’t been in business for at least 4 years, and don’t have good marks on the normal review sites avoid them. If your neighbors have solar – ask them. Of my surrounding neighbors 4 have solar. One used a national company that used a contractor from out of the area to do the install. The contractor and the national company went out of business. One used the same company I did (though I didn’t know it at the time), and another used a large regional company that as of this writing is still in business, but getting hammered pretty hard by the latest rate changes and high interest rates.
  5. Do some investigation on the components, methods and limitations of any system you consider. Not all estimators/installers appreciate the complete landscape. They tend to stick to what they know (if indeed they know!). In part 2 I will provide a list of question I suggest you ask.
Chart 5: December and January Production. The thick horizontal Red line is our average household load. The solar panels were turned on on December 7th. Notice December 18th through 24th only ONE day (December 23rd) exceeded our average household load. Once the system was turned on, we didn’t need ANY grid energy for the first full week

2 thoughts on “Going Solar – Part 1

  1. Bruce Lathrop

    As always, Steven does a thorough and comprehensive analysis as well as an understandable explanation for his readers. Great job, Steven.
    I wish I new more on how to “qualify” potential solar panel quality, as well as the companies who install them. I remember several years ago my composite roof contractor told me the Panasonic solar panels are the best and most efficient of the ones available. I wonder if that’s still true?

    1. Steven Christenson Post author

      Equipment is changing pretty constantly, unfortunately. At this point my take is to treat solar panels and equipment like you would an appliance or camera purchase. Stick with brands that have proved trustworthy and have been around a while. You may not get the MOST bang for the buck, but a reliable, healthy business is always more fun to deal with than a “here today, gone tomorrow” business. In Part 2 I do have a bunch of questions to ask your proposer/installer. I’m still tuning it to be as concise as possible. By the way I’d also say that what you get may need to be moderated by availability and installer familiarity as well as, and including cost.

      During COVID we remodeled our deck including a pergola over it. We wanted a steel roof on the pergola (not corrugated aluminum or fiberglass) because the previous aluminum roof was cheap and got torn to shreds by violent winds. Indeed in a photo in the article you can see part of that steel roof! But the supply chain was so whacked out that we left it to the builder to choose – I just asked that the top be as light in color as possible to reduce heating! They ended up getting surplus from roofer – and that was fine for us! If you go with a larger installer, they may have REC Alpha (or Panasonic or Canadian Solar) panels in stock already. The differences in panels are not that significant that I’d worry about it. Ours are 410W REC Alpha, by the way. They are premium.


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