We've been exploring the idea of photovoltaic (PV) solar for a while, but are now pulling the trigger. Of course, the Coronavirus pandemic hasn't made this easy, but hopefully we can start to compile a team to get panels on our roof sometime this year. I'll create a few posts to try to keep things in one place for all of the parties involved.
Step 1 // Identifying the goals
There are a lot of reasons people might choose to install PV-solar. For us, the primary driver is cost-savings. Our average electric bill is about $300/month — higher in the summer with air conditioners and lower in the winter when the gas kicks on for the boiler. With solar, we'd opt to use more electricity and less gas (i.e.: use the mini-splits in the winter for heat) — then there's the eventuality of an electric car at some point (for everyone — not just us). If we were to boil down our motivating factors into a list:
1 // Architectural Integrity
In the Eichler-built house, we've paid a significant premium on all fronts to live in an architecturally significant house — and we obviously embrace that. This is a big driver with all decisions. The yard is not landscaped with roses. There are no Colonial-inspired accents... the list goes on. There are many homes in the neighborhood where the solar array is simply an eyesore. We will take a hit on efficiency to have the panels in an aesthetically pleasing arrangement, but if we can't install them in an invisible way, we simply won't take the plunge. Why spend $30,000 on something that you'll regret every time you pull into the driveway? This is also be a significant determining factor when selecting a vendor. Some will understand — and be willing to work with this obstacle — and some will not. That's OK — the Eichler home isn't for everyone either.
“... if we can’t install them in an invisible way, we simply won’t take the plunge. Why spend $30,000 on something that you will regret every time you pull into the driveway?”
2 // Cost Savings
With a $300/mo bill (and less gas use after solar), it's one of the few things that have a trackable payback on the renovation front. Also, with more-and-more work-from-home days, energy use will rise.
3 // Electrical Independence
While we're not opposed to a system that is "battery ready", we're not looking to add a battery at this time, but instead integrating a transfer switch or interlock so that the system can work with a portable generator — and even better, if the solar system can be disconnected from the grid and serve as a "solar island". We had no days of power-outage last summer and adding $15K battery to the overall bill for very little risk does not make sense at this point.
With PG+E cutting power in the summer, having a back-up source of power will be essential for California residents. Solar will help with this, but not if it goes down with the grid. There are a number of options to investigate including the integration of a transfer switch (or interlock) which will enable hooking a petrol/LP-powered generator to the house. This is something that we want to plan in conjunction with the solar installation. This also might play into the choice between Microinverters and Optimizers.
Some hypothetical scenarios:
- Power is on // Solar is working ... we both feed and take from the grid. This is the normal scenario.
- Power is off // Solar is not working ... and we back-feed the house/panel via interlock or transfer switch with a generator.
- Power is off // Solar is working to feed the house during the day as it can (island) ... and we supplement the panel (back-feed) with a generator.
Some things are possible — some are not. Some are code-compliant — some are not. This is why we're talking to the pros. In the end, having a battery available and being able to more truly "island" might be the long-term answer, but we want to investigate options.
6 // Pool Heating
Edit: We've crossed this off the list... We have a new natural gas heater for the pool (installed in 2018 with the pool)... and considering the pool gets to 85 degrees on it's own by June — and any additional system will cost far more than natural gas...
The pool currently uses a natural gas heater (when we actually use it). However, by June, the pool heats up via the regular sun anyway, so we'd only use pool heating a few weeks anyway — and the safety cover retains a good bit of heat. Additionally, with PV in the mix, we can replace the gas heater with an electric pool heat pump down the road and avoid having hundreds of gallons of water being pumped up to our roof — and be able to cool the water if needed. Less roof penetrations, fewer systems, more efficient pump usage, controllable water temps... but, since any pool heating system will cost at least $4K, it's important to note that we already have a natural gas heater... and $4K will buy a lot of gas.
7 // Eco-mindedness
We already have a choice to pull grid-power from more sustainable sources via the electric company... and it's not that we don't care about the environment (of course we do), but since we can already make this choice at the grid-level, it's not as much of a driver when on our roof-top.
Why skip #4 and #5? Because the first three are that much further ahead than the last two. It's worth mentioning #6 + #7 as they do come up, but it's also important to focus-on-the-focus:
- 1 // Be respectful to the architecture
- 2 // Self-generation of power, and
- 3 // Being able to use that power when we need it...
(c. 2018) Google street view isn't always the most flattering, but at least it's timely. The goal is not to see any evidence of solar from this point-of-view.
Step 2 // Vendor selection
Fortunately, we're not alone in this search as many friends and neighbors have stepped down this path. Each have had varied success based on our own goals above — which they might not share. It's important to recognize this because, while we might cherish a neighbor, we can simultaneously not love their solar panel arrangement — or at least not want to pattern ours after theirs. When scouting and gathering pictures, this will be a guiding thought. However, their experiences are valuable and we've gotten some great tips — primarily vendor selection. The first four vendors — in no particular order:
• Diablo Solar (Mike) // Our friends/neighbors Margaret + Carol and Mike + Shondra both used DS and both rave about them. Mike + Shondra have the same model in the same position as us, so that will be a good reference point.
• Got Watts (Rick + Chris) // Our friend David in an adjacent neighborhood is now working with GW. David is a thorough guy and GW would not have hit his list without significant research. Leveraging the expertise, time, and effort has been a key driver in the renovation as a whole — why stop now? Chris was the first onsite measuring some things — pics below — and, with an electrical background, he was able to add some insight to #2 above.
• Your Energy Solutions (Jim) // Dan used to live near David. Dan is also my go-to for tech (and 80s music) stuff. Dan likes things that work efficiently (like me) so, again — trust your friends, right?
• Solar Harmonics (Jamie) // Solar Harmonics came through a general Concord-community recommendation. While not Eichler-specific, there's no need to limit the search and SH comes highly recommended by dozens of folks. Jamie was the first we talked to about the project and he was very helpful with a few basic questions.
The goal is not to pit one against the other, but it's fair to let folks know who else might be showing up to the party — and share best practices, basic information, etc. Transparency is important to us, to let's keep that up. Jamie mentioned: "Yeah, these are all good folks — and it's good to hear. The only really disappointing thing to hear that a client went with someone not on this list simply because someone else knocked on their door... and then they call us back with concerns". I found this to be a well-stated and fair POV — and the kind of thing I like to hear during a kick-off. There's not need to disparage a competitor — and people who don't play well with others are not someone you want on your team. Also, folks that have the time to go door-to-door selling solar might not be the best, most in-demand folks.
Since the shelter-in-place has lifted, we've gotten call-backs from each of the above and we're just starting the exploration and bid-gathering phase of each. All have been great to work with so far.
Step 3 // Gathering bids
This is where we're at now. We'll keep adding as the project grows and let this post serve as a repository of all things: wisdom, pictures, questions, goals, etc.
We've had great initial response from all of our vendors and very good follow-up from two. Two were willing to review the project site — one in person and one virtually. This is a complex job, no doubt, and pulling a form-estimate from a typical rancher isn't going to work well.
All bids are coming in at about the same level apples-to-apples which is great to see. Of course, higher efficiency panels and other options are more expensive, but everyone is in the $35K range (plus or minus $5K). This is pre-refund pricing for a 24-27 panel system (about 11kwh — give or take 10%)
In the end, it will likely be less about cost and more about how any vendor might be able to deliver against the 1-2-3 points above.
Step 4 // Choosing equipment
After a few very fruitful discussions with vendors, we've been given some (naturally) conflicting information on a few things. I say "naturally" as each vendor has what works for them. For instance, in my renovations, I'll only install Milgard windows and Toto toilets — I've never had a callback on either (but I've had problems with others). This is natural and something we were prepared for. We'd never want a vendor to install something that they don't feel they can stand behind.
Microinverters vs. Optimizers: The two power management systems between the panels seems to boil down to two choices:
• Enphase Microinverters
• Solar-Edge Optimizers and Main inverter
... and, of course, there seem to be pros and cons for each. However out of our four vendors, one has said "stay away from single inverters" and another has said "stay away from microinverters". Who to believe? Which is better? Which integrates better with our wants (generator integration now and battery integration later) and which is longer lasting?
Microinverters: These convert DC to AC power on the roof. Each panel is independent and seems to be able to integrate well with other technologies (battery / generator). However, with the conversion happening on the roof, they are not quite as efficient and if one goes down, it's more costly to replace. Given the hot roof and the heat that the inverters generate, the immediate environment is hot-hot... which is bad for electronics. However, with the tech under each panel, there's a space savings down below at the panel.
Optimizers (+ single inverter): These supply DC at the roof and convert to AC on the ground. There is a larger, heat-producing inverter on the ground — in our case, this would likely need to be in the garage (losing garage space) and it would generate in-the-workshop heat (why not outside? its blazingly hot on that wall and it's already crowded with pool equipment, gas meters, etc... there's really no space outside). However, if something breaks, it's a single replacement versus, like, 30 at the panel level. Also the inverter seems to be more tech-dependent — some work with specific batteries and some don't.
The above is super-simplified and might even be not-so-correct — we're validating some of this intel as I type... but as you might imagine, there's a lot of divergent information.
Step 5 // Documenting it all
As mentioned above, Chris was the first on site to take a look and measure things. I followed him up the ladder to snap some pics of the roof — and climbed back down to take some shots of the electrical panel(s) which will be helpful later on.
Roof
Here's a shot of the roof looking towards the back of the house. I've housed other roof images here for closer inspection if necessary.
This stitched shot shows the roof looking toward the back of the house.
The pitched portion of the roof is low... Chris was kind enough to let me take a snap of his measurement.
Roof Pitch
I've ventured onto the roof, onto the internet and into Adobe Illustrator and drafted this map. It's available here as a PDF. It's fairly self explanatory and IDs the most relevant obstructions and prime areas.
Electrical
We have three panels...
• The original panel (100A) // This has been upgraded and is now a sub-panel, but this 100A panel powers the original house circuits
• The main panel (200A) // This was added when we upgraded to 200A service. It feeds 100A to the old panel (above) and houses new circuits for the ACs, the pool, the workshop, and others
• The back panel (formerly the "pool panel") // This 60A sub-panel was added when we installed the smaller pool in 2012. Presently it's only feeding two small 20A circuits for the boiler room and back yard, but it's nice to have an electrical point here if needed later on.
Below are a few overview shots. I've included more here.
Above: The main panel (open + closed)
Above: The original house panel — now a 100A sub-panel
Above: The back panel — now mostly unused
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