With so much attention these days on solar panel manufacturers, it is appropriate to focus the first part of this 5 part series on the main driver of a solar electric (PV) system. This article will focus on the territories or the United States we are most familiar with such as Minnesota, Wisconsin, Louisiana, North Carolina and Illinois, and how the solar panels produce power in them.
Consumers are often confused by misleading marketing strategies on Efficiency, Company Strength, Performance Warranties, Durability and Real World Output. Our extensive product procurement process takes this into consideration and are outlined, in our professional opinion, based on intense experience, and diverse national experience with many of the industry leading manufactures.
Solar Panel Efficiency- Panel efficiency is often the most misinterpreted aspect when it comes to comparing solar panels. Efficiency from solar manufacturers is almost always on data sheets, but should never be used as the leading indicator against power production in real world circumstances. With a large gamut in efficiency ratings, the main consideration when comparing efficiency is how much space will be required to generate the overall power.
Efficiency on panels is very different then efficiency for a product such as a water heater, refrigerator, or an air conditioner. In the case of solar panels, rather than indicating how an appliance uses energy, efficiency is a reference to its ability to convert all of the suns energy on a scale of 1,000 watts per meter squared. Therefore, a higher efficient panel simply takes up a slightly less area to produce the same power, a 10% efficient solar panel vs. a 20% efficient solar panel rated at 200 watts simple means the 20% panel takes up half the space of a 10% module to produce the very same 200 watts.
A typical solar panel module floats around a panel efficiency (not to be confused with cell efficiency, which is always slightly higher) of 15%, this area of rating provides the best bang for your buck or your fastest return on investment with maximum overall durability.
I often get asked about record breaking efficiency and "why shouldn’t I wait until the technology gets better". This is often misleading as what makes the news is the efficiency that we see hitting satellites and are financialy unreasonable from an investment standpoint. There are some technologies that have been making some waves for quite some time such as printed cells, new manufacturing process, etc; however, the current polycrystalline modules are a durable product that are perfected, and will be here now and into the future as the core panel product.
The last item when discussing efficiency is specific to the 2 core types of modules, Polycrystalline and Monocrystalline. Poly is taking over the mass market as it is a more stable product than Mono, which though slightly higher in efficiency out of the box, suffers from a 1styear power output cliff that reduces it's efficiency in the field to that of a Poly panel. Mono panels often cost slightly more as with all the very high efficient modules, so much so sometimes that Return on Investment is extended by 2-5 with no additional power output benefits. In our expert opinion, this makes a 15-16% efficient Polycrystalline module the best selection for 95% of all solar projects.
Manufacture Strength- With what seems like monthly headlines of “Another Manufacturer goes out of Business”, it may seem daunting to how the actual solar market doing. It's doing Great! With almost every manufacturer as of the end of 2012 operating their businesses in the red to jockey for position as the leader in a market, trying to be here to stay, you, the consumer are reaping the benefits. With that said, manufacturer strength can seem daunting, and selecting a manufacturer to back there warranty is often a blind toss up, but there are some indicators to make the best discision.
I personally spend many hours a year qualifying these manufactures and often rely on many sources to establish an overall picture of company strength. As of the entire year of 2012 USA solar panel manufactures seem to taking the biggest hits in competing with companies in Asia and Europe. We have seen many US manufactures close their doors this year and a retraction out of the US by European manufacturers.
Solar Panel Warranties- Warranties of panels have fallen into a standard 10 year defect warranty, and a 25 year production warranty. At 25 years the solar panel manufacture guarantees an 80% power output as compared to its nameplate rating; therefore, a 250 watt panel at year 25 is guaranteed to have a power output of 200 watts. Many solar panel manufacturers have a 2 tier output guarantee during these 25 years, 90% from 0-10 years and 80% from 11-25 years meaning any large drop would still be warrantied. Top teir manufacturers use a linear warranty, that gradually goes down, ensuring there is no large power production loss in any given year. This type of linear warranty is the market leader at this time.
Product Durability- Most of the major brands on the market have very similar manufacturing processes that are related to product durability. I have spoken to customers that have had panels up since the 1980’s and they have survived many hails storms and terrible weather conditions in MN and WI weathers as well as the hot and Humid Baton Rouge, LA summers.
Most panel manufacturers are rated to survive at minimum 1” hail stone at 55 MPH at a 90 degree angle, making it debatable how much larger would they survive. I have personally been installing systems since 2006 and have never replaced one single module for hail or warranty issues making, them a very robust product. Some manufacturers offer better framing allowing for a more diverse installation options, helping improve installation aesthetics, which at Able Energy Co. we weight very heavily.
Practical Power Output- I saved the most important topic for last. Every solar panel system installed throughout the United States relies on one thing, power output. Whether you are in Minnesota, Wisconsin, Illinois, Louisiana, North Carolina, New Mexico, Arizona, or Hawaii, power production is the name of the game and, this is the largest distinguishing factor in solar panels. Power output pays for a system and saves its owner money. In evaluating a solar panels real world output, vs. “a lab number” or a "flash test" we rely on one source, which is the go to for the international solar industry, Photon Laboratories.
In short, Photon takes voluntarily submitted modules from manufacturers and tests them in a field for one year, tracking each panels actual power output. The results have been a great breath of fresh air to installers and consumers everywhere on what they can actually expect out of each manufacturer. We have seen some of the manufacturers doing a little cheating by submitting a module that is either no longer in production or haven’t had plans to large scale manufacture in an attempt to gain exposure. And being that Photon does an excellent job of indicating these modules, it is very evident which models are still in production.
Our Selection(s)- At Able Energy Co. we take selecting our modules as a balance between all of the above sections, considering each factor heavily, and weighing each equally. If we are bias more one way than another, it is towards real world energy production, as this is the ultimate payout of a well designed system. When considering price, as a ratio, and in reference to the attributes discussed above we can come to a conclusion on “Value”, our favorite word at Able Energy Co.
Each of our projects and customers has their goals and expectations, and we offer a brand that fits into the selection process on the top of the list. We are not beholden to any one manufacture making our selection as unbiased as we can make it.