One Solar Installation, Five Stocks


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Invest In What You Know

"Invest in what you know" is an old stock market adage.  The idea is that, if you have some personal knowledge of the real economy, you can use that to make better investments.  

How useful this adage is depends on how you apply it.  If you know more about a stock market sector than other investors because of "what you know," it's possible to make better investments because you may be better at spotting future trends.  If, on the other hand, you feel you know a sector because you buy its products, you may get caught up in a herd mentality and end up buying a company (along with a bunch of its other customers) just when the popularity of its products peaks along with its stock price.

I'm a recent customer of the solar industry.  Last week, my solar installer flipped the switch on my new solar PV system, and my meter started spinning backwards.  Like many new solar owners, I'm a bit obsessed with the system.  Here, I'm channeling that obsession into an article about the companies that supplied parts of the system, and what we can learn about their prospects.

The System

Solar systems are far from uniform, and vary significantly depending on energy usage, location, available space, and local incentives.  My system is a little larger than average, at 6.6kW. I have a fairly high load because last year I installed air source heat pumps to supplement my oil-fired boiler.  My two-person, 2000 square foot house in New York's Hudson River Valley uses an average of 13 kWh a day outside the heating season, but add another 10-20 kWh a day during the four-month heating season, for an average annual usage of 21 kWh/day.

According to my calculations using PVWatts, my 6.6kW system should produce just about that much in an average year, but my solar installer used more conservative numbers, and expects it to produce about 20kWh a day.  Below is a monthly production and usage chart based on my calculations.

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Because my usage is highest in the winter, and my production is highest in the summer, I will be relying on net metering rules to "bank" kWh produced from April to October to be used for heating from November to March.  My utility requires that this kWh bank be trued up once a year, which I will set in March or April.  I've shown the true-up here in March, where I'm "billed for" negative kWh (i.e. paid by the utility.)  

This "banking" is actually to the utility's advantage because, not only do they effectively get an interest-free loan of electricity for an average of six months, but New York electricity prices tend to be a little higher in the summer than in winter.  Since 2005, only 2014 had a higher peak winter price than the previous summer peak.  Last year's exceptionally high winter prices were caused by locally high natural gas prices, in turn fueled by the polar vortex.  The utility also benefits from daily production swings: Solar production is highest when hourly prices are highest in New York.

Although the utility receives significant benefits from my solar system, it is also a good deal for me, mostly due to Federal and State incentives. If I assume electricity price increases completely offset system maintenance costs (I expect them to more than pay for any maintenance), my expected internal rate of return over 30 years will be 9.7% (or 8.3% over 20 years.)  The payback of my initial investment will take about 9 years. Without subsidies, the 30 year return would have been a paltry 1.9%, with a 22-year payback.

I expect that many New York solar systems have even better returns than mine, because I made a number of decisions which raised cost without increasing electric production.  First, I wanted to reserve part of my roof for a future solar hot water system, so I chose somewhat more expensive monocrystalline panels in order to make the most of the roof space I was willing to use.  Second, I decided to go with SMA TL-US strong inverters rather than microinverters because TL-US inverters can provide some back-up power when the grid goes down.  Third, I had to do some upgrades to the frame of my garage and attic of my old (1930) house to support the extra weight of the panels.  Finally, I wanted an awning to protect a third floor balcony from rain, and so I had my installer project the edge of the panels past the edge of the roof to serve this function, making the installation more difficult.

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Long ABB.

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