A: Solar panel efficiency actually increases as the temperature drops. It decreases at higher temperatures. However, the effect is quite small.
Q. My house has solar, but because the company that installed the panels is now out of business, the monitoring of the solar is inaccessible.
Q: Is there a third party monitoring system that could be added to an existing system so that I can see more than just my net usage, but actually see if my solar panels are producing as I’d expect? Is there a way for people installing solar from the beginning to ensure that monitoring will remain available (open source access)? Is that common in single family homes?
A: Do you know who made your inverter? It is often SolarEdge or EnPhase. The app for your smartphone (and the web portal) comes from them not the installer. I think if you contacted them they could sort it out for you. If that does not work let me know. You will not be the only person in this situation as solar installers go bankrupt quite often.
Q:solar panel disposal also is a problem as they are replaced with more efficient ones
A: A solar panel is made from silicon, glass and metals. All are valuable and easy to recycle. Solar panel recycling is starting to become more commonplace as older panels from the 1980s start to get replaced with more efficient ones. There are already solar panel recycling facilities in MA, such as CED Greentech.
Q: Are there solar systems that will provide enough power for our home during a power outage?
A: Yes, but probably not the whole house, probably only the circuits you would power from an emergency generator. Since solar panels must, by law, disconnect from the grid during power outages (to prevent the linemen getting electrocuted by your solar power) you will need to install a re-connect switch at your electrical panel just like that for a back-up generator. This usually needs to be installed with a battery, but when the grid is out and the sun is shining you will be powering the house from the sun. Nice. I intend to do this on my house this year. I have just ordered batteries to be installed at my house to replace our ancient (and no longer working) propane generator.
Q: What if you need to put on a new roof within a few/several years of installing solar.
A: I replaced my 20-year old roof before adding solar panels. Taking the panels off to install a new roof will cost you more money, so if the roof will need replacing within the next few years, I think it is better to do it now. Solar panels will extend the life of the roof because it is the sun that deteriorates the asphalt not the wind and rain, and with solar panels, the asphalt is now shaded.
Q: Have you looked at Tesla solar roofing tiles?
A: I have, and I have concluded that they are just too new to even be considered at this point. A roof is a long-term investment. Until there is some data from roofs other than that on Elon Musk’s house, I will be cautious of these new products.
There have recently been a few reports from people who have installed the Tesla solar roof. The numbers are not encouraging. The Tesla solar tiles are only about 4-5% efficient compared to solar panels that are about 20-21% efficient. The cost of the installed power is about $4.62 per Watt compared to solar panels at around $2.80-$3.00 per Watt. The Tesla solar roof is about 50% more expensive than solar panels and about one quarter as efficient. I was right to be cautious of this new product.
Q; What if your roof has too many gables and “wrong’ angle for solar panels?
A: Complex roof lines reduce the number of panels you can fit on a roof. Almost all solar installers today use a software package called Aurora that calculates how many panels can fit on a roof using satellite data on the angle, shade and orientation of the roof. I have found it to be very accurate. If your roof cannot fit enough panels to cut your carbon footprint to zero, I suggest looking at community solar options. There are several companies in MA that offer this. They build large solar-panel array in big fields in MA and sell you the net-metering credits at a discount of usually 10% (one offers 12.5%) to the utility price of electricity. These net metering credits appear on your electric bill. This is a very good option if your roof is not suitable for solar panels.
Q : What are the most efficient solar panels available as of now?;
A: SunPower panels are about 22% efficient. Solaria, Panasonic, LG, REC are about 20-21% efficient and there are many companies (mostly cheaper brands made in China) that are in the 15-19% range. However, most efficient electrically is not the same as most efficient economically. For this, calculate the cost per kilowatt-hour generated by the array over the period for which the electricity output from the panels is guaranteed by the manufacturer. Today this is almost always 25 years. So if you have a 10kW array generating 10,000kWh per year (both fairly typical in MA) and your array cost $30,000 before the subsides and $15,000 after the federal and state subsidies then your cost of electricity (sometimes called the levelized cost of electricity or LCOE) is $15,000 / (10,000 x 25) or about 6c per kWh. To me this is the better way to look at efficiency and not the stated electrical efficiency of the panels.
Q: What about snow collection on a flat-mounted array?
A: The panels can easily bear the snow load, including during that winter a few years ago when we had 6’ of snow.
Q: are there solar installers that will install on slate roofs?
A: Not that I know of. It is very difficult to seal penetrations through a slate roof.