Archives September 2020

Going Solar, Part Three: Waiting for permission

What to do while you’re waiting

The adventures of installing rooftop solar panels on an existing home

Now we wait. Whiling away the hours by reading the warranties and contracts.

HOA

My homeowners’ association (HOA) must approve any changes I make, particularly regarding the exterior appearance of my home. In Nevada and other states, the HOA’s ability to keep me from installing solar panels on the rooftop is limited by legislation meant to encourage renewable energy. As I understand it, they cannot refuse to allow panels. They may, however,  require changes that might reduce the output of my system as much as 10%. That would put a real dent in my payback. They may also take their sweet time, up to 45 days according to Nevada Energy Commission, to approve my application. I’m on day 28 now. 

[I later learned that the regulations of my HOA allow that if I make an application and get no response, after 30 days I can assume it’s approved. I wish somebody had told me to take a closer look at the HOA CCRs.]

At request of my solar provider, the HOA sent me a standard application form. Among other things, the form asks for the signature of all my surrounding neighbors indicating if they “approve” or “disapprove.” In the case of solar panels, it’s my understanding that the neighbors’ approval is not required. In my case, getting neighbors’ signatures is complicated. During a pandemic it doesn’t seem a good idea to go door to door getting signatures. Also, the homes around me are rentals and it might prove daunting to try to get approval from out-of-state owners. I filled in “Unable to obtain due to COVID-19.”

The solar provider filled in “December 3” for the installation completion. That’s more than twelve weeks away but we all hope it will be sooner. They don’t get paid until I sign off on the installation.

Building permits

City, County and other authorities must approve the plans before installation begins. This can take 8 weeks.

Warranties

I’ve been reviewing the warranty information provided by the solar contractor. With the exception of the roof, they’re standard manufacturers’  warranties.

As always with warranties and their loopholes, you’ll be dependent on the good will of the company to stand by their product, assuming said company still exists in 10, 20 or 25 years. The average lifespan of a corporation listed in the S&P 500 is now about 15 years.

Photovoltaic Modules: 25 year workmanship warranty / 25 year 90.76% power warranty / 25 year labor warranty. Manufacturer warrants the power output will be no less than 97% of the designated Maximum Power (Pmax) stated in the product data sheet for the first year from date of purchase of the Product by the Customer and the Power output degradation will be no more than 0.26% per year for the following 24 years, so that, at the end of 25th year, the power output will be at least 90.76% of Pmax.

Translation:

Panels tend to produce less power as time goes by. Many panels degrade to 80% capacity or less after 25 years. Mine are “warrantied” to produce at least 90.76% during their lifespan of 25 years. Except, not really.

For one thing, they claim a margin of error of +-3%, so they’re really only guaranteeing 87.76% over the course of 25 years, not 90.76%, and that 3% “deduction” starts at year one.

The way they get to that 90.76% figure is somewhat convoluted, and of course unfair. Let’s say something worth $100 depreciates 10% per year. The first year it will lose $10 and be worth $90. The second year it will lose 10% of the $90 or $9, and be worth $81. After 25 years you’d still have $7.98 left. The way the panel manufacturer calculates it, you’d lose 10% of the original value each year, and would be down to zero after just 10 years. That’s how a rate of 0.26% per year goes from 100 to just 90.76 in 25 years, whereas if properly calculated it would be 91.12. Of course that difference is insignificant compared to their +-3% ringer.

In any case, an underproducing/defective panel may not be replaced with a new one, or even a refurb. Rather, the manufacturer can choose to refund the “value” lost. As I understand it, if a panel is only producing half the power it should, they’ll refund half the cost of the panel. This will probably be small comfort as you dig deep into your pocket to replace it.

If my “superior” panels turn out to have a lifespan no better than the “inferior” models, and is at only 80% after 25 years, if I’m lucky they’ll refund 7.76%, a paltry sum. Their brag about superior lifespan may be true, but it’s not backed up by much of a warranty, at least on paper. They’re no dummies!

Inverter: 25 year workmanship warranty

Power Optimizer: 25 year workmanship warranty

GSM Kit: 5 year prepaid plan (extendable at expiration). This is the communications module for the system monitoring app. GSM provides a cell-phone signal to facilitate remote monitoring. My understanding is the module includes WiFi so I can monitor without paying for the GSM signal. Typical costs for this kind of GSM service are $10 a month, which would weigh heavily in any calculation of return. I hope I won’t need it.

Mounting Racks: 25 years

Contractor Labor and Roof: 25 years. For the duration of the roof warranty, contractor is guaranteeing it’s roof penetrations to be watertight under any weather conditions. In case of a roof leakage after the expiration of the home’s original roof warranty homeowner must prove that the  leakage is actually caused by contractor’s roof penetrations.

Part Four: Snags & Glitches … Overcome

Resources:

PVWATTS calculator

Rough Draft of my spreadsheet. Click “Assumptions” tab after opening.

Going Solar, Part Two: A Secret Way To Save

Secret to me, until now: Time of Use Rates

Solar Panels are good for the environment of course.

The adventures of installing rooftop solar panels on an existing home

There is much to learn! Like Time of Use rates.

Since I posted “Part One” I have had my roof inspected by the solar provider. One cracked tile was found, which they will replace, and they report “the felt is good.” They took photos of all aspects of the roof. I suppose I should get a copy of those. [Advice: ask for anything special as soon as possible, preferably before signing the contract. I requested photos after the fact and was ignored.]

They say they will be providing a 25-year warranty on my roof. That protects against leaks from the points at which they attach their panels to my roof.

Meanwhile I’ve been refining the numbers on my spreadsheet. Savings each month will vary according to how much solar is used and how much is taken from the grid. It is not simply the total generated minus the total used, because I only get a credit of 75% retail from the utility. So the more I use solar instead of the grid, the less I pay. I can calculate a maximum savings (all solar used, none sent to the grid) and a minimum (no solar used, all sent to the grid). For projections, I’ll use a figure midway between those two points.

Solar is not a substitute for conservation.

Solar panels on your roof does not mean you should use electricity with abandon. In fact, you should be conserving energy whether or not your go solar. You may find you save so much money by conserving that adding solar panels is unnecessary or not cost-effective. You need to compare the cost of solar versus your energy use AFTER employing conservation measures, not before.

Change all your non-LED light bulbs.

LEDs use about 1/10 the amount of electricity as old-fashioned incandescent bulbs. They last much longer, and the payback on replacing old bulbs is only a year or two. Your local utility may even provide some new light bulbs for free.

Turn off outdoor lighting during the day.

You can use LED light bulbs that turn themselves on when it’s dark. Be sure to get the dark yellow ones that don’t screw up the insects and birds. Ordinary LED bulbs may be screwed into sockets that are only on in the dark. Your local utility may provide some of these for free or at a substanial discount.

Use smart sockets.

Many appliances use electricity even when they are off. Shut them down as much as you can. For instance, kitchen appliances may be plugged into smart sockets that automatically turn themselves off overnight.

Seal doors and windows.

Plug up the cracks that allow cooled or heated air to escape.

Replace old appliances.

Refrigerators, dryers, hot water heaters and air conditioners that are over 10 years old are probably wasting energy. Your local utility may provide replacements for free or a substanial discount.

Install a “smart” thermostat.

Something like the “Nest” can reduce your electic usage by identifying times when you can be cooler or warmer. You can set it up to “pre-cool” your house on hot summer days, so you use less energy during peak times. Your local utility may provide a smart thermostat for free or a substanial discount.

Time of Use Rates

My research led me to something called “Time of Use Rates“. This is a plan that might provide savings to almost anyone, but especially for those with solar panels and a bit of discipline. Or it might be a total loser for those who’d rather not think about how they use energy. I’m going to give it a try, and I’m told I can cancel after 12 months and get a refund for any overage. All I had to do was notify NV Energy that I’d like to try those rates.

Basically they charge more (3.5 times as much, about $0.43/kWh!) for energy from the grid 1pm-7pm during summer weekdays. At all other times (evenings, weekends, wintertime) I pay about half the standard rate, $0.06/kWh. Sounds like if I’m willing to sweat a little during the summer afternoons, I can cool things off at night while saving money, perhaps 25-30% of my bill.

I don’t know if or how this affects the credit I get for kWh sent back to the grid. Most likely my credit fluctuates with time of use. Either way I’m bound to be using solar during those summer daylight hours and unlikely to ever pay the pumped-up peak price. As I learn more I’ll update this post.

Shift your usage!

In summer, when TOU rates from 1pm-7pm are outrageous, avoid using appliances and air conditioning. Dinnertime should be 7:30 or later to avoid using cooking appliances during peak. No dishwasher, washer, dryer etc. I pre-cool the house down to 75° from 11:45am to 1pm during summer weeks, then turn the thermostat up to 81° until 7pm. Today it was 106°. From 1pm to 4pm the inside temperature drifted up from 75 to 81 and the aircon kicked back on. It didn’t take much to keep it below 81 from 4 to 7.

In wintertime, when TOU rates are low all day long, shift appliance usage to the time when your solar panels are producing the most, 10am-3pm.

At this time it looks like TOU rates might cut $30-60 off my monthly bill, but will be even more beneficial once I switch on the solar.

My solar rep never mentioned “Time of Use”, probably because it might reduce my existing electric bills, thus reducing the cost-effectiveness of installing solar panels. When I asked him about it, he replied, “I think that is a great idea for everyone who has a solar system on their roof.”   

In California, solar users who employ “net metering” to sell power to the grid must also adhere to “Time of Use” rates. There’s an article at Energy Sage but I can’t vouch for its accuracy, nor the comments.

Compare solar to what your electric bill should be, not what it is.

If you reduce your electric usage through conservation, you will need a smaller, less expensive solar panel setup. This affects costs and payback.

Don’t skimp on capacity.

Your objective is to produce as much electricity each year as you use. If your system produces too much, you’ve paid for capacity that has a relatively poor payback. Too little and you wind up shoveling too much cash back to the utility. Given the basic costs of designing and installing the system, don’t skimp on capacity.

Some solar contractors may low-ball your system capacity in order to provide an attractive price, but this is detrimental to your long-term payback.

Part Three: Waiting, and what to do while you’re waiting

Resources:

PVWATTS calculator

Rough Draft of my spreadsheet. Click “Assumptions” tab after opening.