There’s considerable emphasis put on the brand and type of panels that solar companies install. MOXIE only uses solar panels from guaranteed Tier 1 companies for example. But what does that mean? What are Tier 1 solar panels?
First, solar panels with blemishes, cracks, or other problems, have decreased output. This can happen to any panel. Often, customers can get a refund or replacement for a faulty panel. In other cases, if the efficiency falls below a rated level, there’s a different type of guarantee for that (see below). Warranties vary by manufacturer.
The term “Tier 1” is a designation from Bloomberg New Energy Finance (BNEF) given to companies with a long-standing reputation. They distribute the T1 list quarterly and to purchase a subscription for the “official” list, you must contact them directly. (There’s a link to an unofficial list below.)
Technically, there’s no such thing as a Tier 1 solar panel. There are only solar panel manufacturers on BNEF’s Tier 1 list. See the difference?
But for this blog, we’ll be using the T1 term in the broadest sense possible.
BNEF’s T1 list was developed to inform investors about the companies who provide PV panels. It can be a starting point for researching panels. But ultimately, the BNEF list says nothing about efficiency, a key metric for assessing solar panel output. We’ll go into efficiency a little bit below.
Tier 1 solar designation is not necessarily a reflection of the quality of the panel or line of panels. Instead, it’s a guide to the solar panel manufacturers.
BNEF Tier 1 Solar Panel Qualifications
According to their guide, BNEF’s key criterion is “bankability.” BNEF can remove a T1 company from their list at any time. However, most T1 companies are perennial solar leaders. The main criteria for Tier 1 panel manufacturers are:
- T1 PV module manufacturers own their own production facilities.
- Tier 1 companies supply panels to six different projects over 1.5MW each.
- The projects using T1 panels must be financed by six different banks in the past two years.
From BNEF’s 2020 methodology guide: “This [T1] classification is purely a measure of industry acceptance, and there are many documented examples of quality issues or bankruptcy of tier 1 manufacturers.”
Why is bankability important?
In essence, the Tier 1 list is a financial reference for investors backing solar farms.
They consult BNEF’s list of T1 manufacturers to assess financial stability and longevity of the companies. Why would you consider T1 panels? Mainly because a warranty from a bankrupt company is meaningless.
What is tier 2 or tier 3?
Technically, there’s no such thing as a tier 2 panel or T2 manufacturer. There are no T2/T3 lists. BNEF doesn’t publish a list with that official title. Generally, it’s assumed that T2/T3 manufacturers are those not named on the T1 BNEF official list. That’s the rough definition we’ll use here.
Basically, a so-called tier 2 panel can easily be as efficient as a Tier 1 panel. Maybe the T2 producer’s manufacturing systems aren’t fully automated. Maybe they assemble panels from purchased parts. Or they haven’t supplied panels to six different projects over 1.5MW in the past two years.
Tier One Solar Panel Quality
T1 panels can have blemishes. T1 panels can form cracks after years in hot and cold temperature extremes. And all solar panels lose efficiency after time or in hot weather.
But manufacturers, like SunPower, LG, Q-Cell, Mission, and Panasonic, also have efficiency guarantees that cover accelerated losses. These are called “linear performance,” “power,” or “production” warranties. These warranties are in addition to the product warranty. Check with MOXIE for more information.
“Tier 1” does not necessarily mean the panels are “the best” or most efficient.
BNEF’s methodology guide states clearly:
“We strongly recommend that module purchasers and banks do not use this list as a measure of quality, but instead consult a technical due diligence firm such as Edif ERA (formerly OST Energy), ATA Renewables, Sgurr Energy, DNV GL, Black & Veatch, TUV, E3, STS Certified, Clean Energy Associates, Solarbuyer, Pvbuyer, Enertis, Oravia, Leidos Engineering or Phoventus. These would usually consider what factory the module comes from, as well as the brand, and give an informed opinion on whether the modules will perform as expected.”
However, BNEF gives no determination of quality based on efficiency ratings, temperature coefficient, or warranties. The sole purpose of their T1 list is to provide a guide to the “bankability” of solar panel manufacturers.
Solar Panel Efficiency
Solar panels are measured for efficiency under ideal temperature conditions. That’s about 77 degrees Fahrenheit, or 25 Celsius. In these conditions, most panels produce electricity at about 20% efficiency, give or take.
Solar panels can only convert light energy, not heat. Additional heat is no benefit to solar efficiency. In heated conditions, photovoltaic panel performance decreases.
When a PV panel is warmed up, the current (rate of flow of electric charge) will increase, but the voltage (the difference in charge, kind of like the water pressure in a tank) decreases.
A temperature coefficient of -0.25 means that the panel will decrease in efficiency by .25% for every degree above 25°C.
So if your -0.25 panel is heated to 30°C (86°F) and has an efficiency of 20% (under standard testing conditions), their efficiency at 40°C goes down 3.75%.
In this example, a 300-watt panel, rated at 20% (STC) goes down to 289 watts at 40°C.
Solar Panel Ranking and Type
There are two more things to consider for solar panels: silicon cell construction and facing.
Monocrystalline panels contain a single piece of silicon. In general, they have a higher efficiency rate.
Polycrystalline panels are cheaper to produce and tend to have a blue hue. Manufacturers melt pieces of silicon together to form poly-panels.
The other form of panel is thin-film solar, made from a variety of materials. Thin-film solar is lightweight and flexible. However, performance and efficiency is lower than poly- or mono-crystalline panels.
The other term you may have read is bifacial solar modules.
Like the name suggests, both sides of a biface solar panel can produce energy. Monofacial panels have an opaque backing, just the top side produces energy. Bifacial panels can receive reflected light from a rooftop or ground surface (like sand or light colored stones) to boost production.
All solar panels are not equal.
Beyond the tiers of solar companies, each solar product line has its own data sheet and specs.
Check a list of Tier 1 solar panel manufacturers here. (Note: This list is by Solar Review, not BNEF.)
Why does MOXIE sell panels from Tier 1 solar companies exclusively?
What are the alternatives?
Tier 1 solar panels come from trusted names, like SunPower, Panasonic, Q-Cell, AXITEC, or LG. As a solar dealer, MOXIE finds bulk deals and passes savings on to you.
So will you go with a T1 panel? Yes, if you work with MOXIE, you’ll definitely get T1 panels from certified Tier 1 companies. Absolutely, guaranteed, no doubt about it. MOXIE only sells and installs T1 panels.
We’re not in the business of selling solar panels not found on BNEF’s list.
But we ARE in the business of answering solar questions and providing solar education.