Solar Power Pros and Cons

I made this list of the solar power pros and cons we considered, when we were initially contemplating the idea of getting solar panels installed on the roof of our house in Long Island, NY.

Cons

First, the cons… Ultimately we did move ahead with solar power, but not before considering these elements in the “cons” column.

• If We Wait, Photovoltaic Technology May Advance

This was a biggie… there’s a fixed amount of physical space on the roof, and once you purchase panels, you’ve “locked in” the amount of energy you can produce in that physical space. But over the years, the output per square foot in solar panels has done nothing but improve. So, newer, better panels may come out with advances in technology. We ended up getting 240 watt panels, but were told they are currently working on 250 watt panels which may come out later this year — that’s about a 4.2% increase in efficiency… if they have that kind of increase in efficiency year over year for each of the next five years, the solar panels of 2017 would be approaching 300 watts. That would mean producing 25% more power out of the same real estate.

• Roof Age Timing

The panels in our system are from Sharp and come with a 25 year warranty… Our roof’s remaining lifespan, by comparison, is more like 18 years. So when it comes time to think about a new roof, the panels will still have 7 years left under warranty. At that point, we’ll have to weigh the cost of having them taken down and placed back after the new roof is done, or, getting all new panels even though the old ones would still be under warranty.

• Shade

Shade from trees would be an issue, because the panels need the sun. In our case, fortunately, we don’t have many trees around our house to worry about. But, we did have to consider which sections of our roof are South-facing and sunny, versus North-facing and shady. Ultimately the North face got zero panels in the design; the South and West sides got panels. We weren’t sure — and still aren’t sure — just how well the panels will do in the different areas. Eventually we will have monitoring software that will show what each individual panel produces.

• Aesthetics

It’s got to be a consideration, that your house will look different with solar panels on the roof. It could be considered in the “con” column if you don’t like the look. Ultimately we decided our house would look fine — maybe even kind of futuristic. But it’s definitely something that each person would have their own opinion about.

• Night / Clouds / Snow

The output from any solar power system is going to be variable… concentrated only into daytime hours, and only if it is sunny out. It will also concentrate seasonally here, with the shorter days of winter bringing less energy output. And whenever we get a really heavy snow, those panels could be “asleep” for days thereafter until the snow melts.

• Not Useful As Backup/Generator

There are systems you can get where your panels charge batteries, which you can draw from when the system is not producing… But we are not getting such a system. Instead of feeding batteries with excess power, ours will “feed the grid” and then when we need power beyond what our system produces, we’ll draw it off of the grid. Originally I thought this would mean that if the grid is down (from power outage), that we’d still be able to draw power from our own system. But that is not the case… The system cuts off when the power goes out, so even on a sunny day, if the power is out, our solar power system is not a replacement for a generator.

Pros

On to the pros, which in our case, ultimately outweighed the cons.

• Helping the Environment, Reducing Emissions

Solar is clean; zero emissions. It’s going to make us feel good about doing our part to leave less of a footprint.

• Financial Benefits

This point deserves its own post, and I’ll make one. But for now, I’ll just say that I had always thought of solar energy technology as something that would eventually make sense financially. I was shocked to learn that it makes sense now. That’s in large part due to LIPA’s “solar pioneer” program — they picked up a huge chunk of the bill; in fact their investment was larger than mine after you subtract the federal and state tax credits from my share. I actually only end up paying 29% of the bill, and the remaining 71% is LIPA and the tax credits. And then when you project out the amount of power my system should produce over the course of the year, and translate that into the dollar amount I should save on my electric bill, it works out to a 20% yield on my investment. With a projected return like that, a lot can go wrong and you’re still doing well… I figure even if my system produces only half of what it is supposed to produce, I’m still at a 10% return, and that’s more than 10 times what my bank pays in interest these days.

• Warranty

The Sharp panels, and the inverters, come with a 25-year warranty… That takes a ton of risk out of the equation.

• They Have Microinverters Now

Solar panels produce direct current (DC); an inverter is what transforms that into alternating current (AC). It used to be that your entire fleet of panels connected up to one big inverter. Nowadays they have microinverters, which is a huge leap forward. You have this tiny little inverter for each individual panel, which lives right underneath it on the roof. So, each panel is controlled individually, meaning you can get better overall output, and, you can get really advanced monitoring. I’m really looking forward to that part, when we reach it, there’s supposed to be a web-based system you can point your browser to, and it shows all your panels on the screen, with the amount of power each one is producing (and historical logging too). With that kind of advanced monitoring system, I’ll be able to see how close to the projections my system gets in reality. When we reach that stage, I look forward to posting about it!