The photovoltaic module industry cut its teeth using the same technology as the transistor, integrated circuit and computer chip industry—the highly pure crystalline silicon wafer. An outgrowth of the space program, the terrestrial PV module was brought to earth using the same techniques—but is now developing other materials to generate pollution free dc electrons.
General Questions for Newcomers to the Photovoltaic Marketplace and Certification Testing:
A. Part 1.PMC can save manufacturers time and money.
In the late 70s through the mid 80s the qualification test standard around the world was JPL Block V. This been replaced by the CEC 503, IEC 1215, and IEC 1646. While these are excellent standards, European countries, plus some Middle East and African countries are writing into their purchase specs that theses tests must be conducted by JRC/Ispra! Manufacturers around the world are going to JRC/Ispra because they are afraid that modules tested elsewhere may not be accepted by buyers in Europe, et cetera. These manufacturers are hostage to JRC/Ispra and have to pay their prices and work to their test schedule. According to our clients, the cost for IEC 1215 is $30,000+ and the wait is three to six months before testing begins.
US manufacturers need an organization to represent then in the international marketplace and force the issue of reciprocity. First, PMC can (and is) positioning US manufacturers in the US marketplace by encouraging major buyers to adopt and require the PMC label. PMC does not have to accept JRC/Ispra test results unless it wishes to do so. Until the US creates “incentives” (i.e., barriers similar to those imposed in Europe and other regions), we have no bargaining power. Major purchasers in the US, such as UPVG, SMUD, APS, and DOD have agreed in principle to require the PMC label as soon as PMC certified products are available. Also, PMC, in conjunction with US manufactures, DOE, SEIA, and others can market the PMC program internationally, such that PMC is written into the purchase specifications. (Part 2 will explain why PMC should be implemented by ALL buyers of PV modules).
- Part 2.PMC is a far superior program to any other program available.
CEC 503, IEC 1215, IEEE 1262, et cetera are one time tests. Products that have been tested to CEC 503, for example, are qualified as long as that product is manufactured (e.g. 20 years), even though the quality of the product may have degraded substantially over the years. PMC subjects both the product and the manufacturer’s quality system to periodic (e.g., annual) audits and re-qualification (similar in concept to the UL 1703 certification). This provides the customer with ongoing confidence that the product is reliable and durable.
PMC also verifies that a manufacturer’s modules meet the manufacturer’s power specifications. No other qualification test standard or certification program does this. The PMC label provides the buyer with confidence that the module will really deliver the rated power (at least at STC). This is a powerful selling point!
A. UL 1703UL 1703 IS A SAFETY STANDARD FOR PHOTOVOLTAIC MODULES AND PANELS.
- UL provides evaluations and certification to UL 1703.
- Manufacturers whose products meet these requirements are authorized by UL to apply the appropriate UL Mark.
- Product manufacturing is then audited through a program of factory Follow-Up Services.
- To counter-check products bearing the UL Mark to see if they continue to meet safety requirements, field representatives make frequent, unannounced visits to production facilities worldwide.
- The manufacturing facility is audited with a “Follow-Up Service Procedure”. This Procedure authorizes the manufacturer to use, under specific controls, the appropriate UL Mark on their products. The Procedure also describes in detail the product as it was constructed when it was originally examined and tested.
IEEE 1262 IEEE 1262 PROVIDES ASSURANCE THAT THE PRODUCT IS RELIABLE AND DURABLE.
- a test standard, not a certification program
- a US national test standard that applies to both crystalline and thin film modules
- designed to detect known failure mechanisms in modules which affect performance, reliability, durability, and safety (some overlap with UL 1703)
- incorporates the requirements of IEC 1215 and 1646
IEC 1215 IEC 1215 PROVIDES ASSURANCE THAT THE PRODUCT IS RELIABLE AND DURABLE.
- a test standard, not a certification program
- an international test standard for crystalline silicon modules
- nearly the same requirements as IEEE 1262
IEC 1646 IEC 1646 PROVIDES ASSURANCE THAT THE PRODUCT IS RELIABLE AND DURABLE.
- a test standard, not a certification program
- international standard for thin-film amorphous modules
- nearly the same requirements as IEEE 1262
PMC PMC IS A CERTIFICATION PROGRAM THAT ENSURES PRODUCT RELIABILITY AND DURABILITY.
- product meets IEEE 1262 and IEC 1215/1646 (and retested every two years)
- requires an accredited laboratory
- module performance is measured and certified
- factory is audited periodically to verify minimum quality standards
A. A multi-client testing program at the ASU Photovoltaic Testing Laboratory (PTL) involves conducting PV module tests (per IEEE 1262, IEC 1215/1646, and/or UL 1703) for two to six module TYPES (i.e., models), generally from different clients, at the same. Cost savings of 25% to 50% are provided by multi-client testing. Test results are always proprietary for each client.
A. We need a total of nine modules for IEEE 1262/IEC 1215. A total of 11 modules are required for UL 1703. The same 11 modules can be used for IEEE 1262/IEC 1215. For a 0.7m^2 module, the cost for IEEE 1262/IEC 1215 is $21,333 for our July 15 multi-client test program.
The Photovoltaic modules you put on your building must have the Underwriters Laboratories seal. Too, the module’s design should have been qualified to either the IEEE 1262, IEC 61215 or IEC 61646 standards. UL safety listing, of course, assures the local electrical inspector will approve what you have chosen to install. The National Electric Code requires the UL label. The IEEE and IEC certification tests, by a recognized independent testing laboratory, assures the design and construction of the module meets certain recognized standards, giving your end customer confidence in the product.
Which way should the array face? The rule of thumb is always face the array true South (in the Northern Hemisphere). Oh, there may be exceptions, such as your immediate neighbor to the east is a thousand foot high mountain, and it keeps the sun away from your place until noon every day. Sure, there are exceptions—but not very many!
Keep trees away, or anything that can possibly shade the system—or grow to shade—during its lifetime. Shade is cool for people, but not for PV!
Another rule of thumb is to elevate the array so it is at an angle of around the latitude of the site. Normally placing the modules on a standard pitched roof is fine—and facing south. If one is tweaking things to get the most energy out of a system, PV purists would have the array on a tracker that constantly points the array at the sun—from sun up to sun set, and changes its elevation angle, too, as the sun changes its seasonal position in the sky. Not too practical for the normal homeowner, however. Placing the array flat on a flat roof is OK, but means your system won’t generate electricity at its best.
A photovoltaic array can either be designed as an integral roofing members (such as the Unisolar amorphous architectural modules) or simply attached to the finished roof, using standoffs of 1 or 2 inches to provide air circulation that the crystalline silicon modules need. Include the array as part of a south-facing roof, if you can, so it will look like it’s part of the structure, esthetically pleasing and doesn’t look like a sore-thumb (oops, another unit of measure for that thumb) afterthought.
Some companies are coming out with PV “shingles” that look and act exactly like roofing shingles—except you can also get electricity from them. Others are aiming at commercial buildings where modules can be integrated with and look just like vertical glass exteriors.
Another company is expanding on the shingle concept by attaching PV modules to large (3 feet x 4 feet) roofing tiles that can be used as the roofing structure on flat, industrial buildings. Might be applied to a homeowner’s large, flat roofed garage, for instance.
But for the single family, non-technical homeowner, who is interested in generating green electrons—but not going overboard in the process, either technically or economically, a 1kW grid intertie system will do the trick. Simple, relatively inexpensive and pollution free generation.
What of the homeowner who wants to become a little more sophisticated? What if the concern is to make certain power—at least in an emergency mode—is available if the power company’s lines are knocked out during a lightning (or wind) storm? The simple grid intertie system will go down, too. The power companies, wisely, have said that “we can’t have independent distributed power producers—meaning your rooftop PV array—pumping power into our lines when our linemen are out there trying to fix damage from lightning—or any other cause.”
Should your homeowner want to be “the only beacon in the darkness” when the power goes out, this can be done, but it’s much more expensive. Using that favorite rule of measure, the thumb, you’ll probably find the cost for such a system to be in the range of $8 to $10 per watt. It does provide a degree of independence. The system automatically will disconnect from the power company grid at the first sign of trouble, then switch to the “independent,” or “stand-alone” mode. Power companies like that, as you’ve disconnected your potentially lethal system from their grid. But it will make you the envy of the neighborhood, as you may be the only house on the block with lights—and computers and TV up and running!
But, “there ain’t no free lunch.” The homeowner must have a degree of sophistication to operate and maintain the system. A battery bank is needed to store the energy needed during your emergency. And batteries need maintenance. Too, after a number of years, they’ll need replacement. If your homeowner is clamoring for an Uninterruptible Power Source that will power the house, then this is the system to consider. Automatic controls will keep the battery system charged, will sense when the grid system goes down, then will disconnect the home from the grid lines and automatically begin operating in the “stand-alone” mode—to the chagrin of the non-UPS owning neighbors! As implied, it comes at a price. Not only dollars (a system size of at least 2 kW may be appropriate) but also being able to maintain the system—or have the system maintained. Another implication by that statement? Not too many technicians are capable of servicing PV systems yet. Therefore, the KISS principle should be employed—Keep It Simple Senor(ita)!
A properly designed photovoltaic (solar electric) system will work, and work well, for years. But you as the builder, and your customer, the homeowner, shouldn’t expect more of the system than it can provide. Whatever system is chosen, even the simplest will need homeowner maintenance.
To generate The generation of green electrons today, at this stage of PV market maturity, needs homeowner involvement. The amount of involvement depends on the homeowner, and can range from simply keeping things clean, to complete immersion and being known as the “nerd of green.”
The simplest system is the “grid-intertie.” This is a PV array (an array is simply a bunch of PV modules connected together) that generates direct current of, let us assume, 1,000 watts. Because it is DC, the normal household needs to change it to AC before household appliances can use it. This is done with an inverter, and it is simply tied to the power company. Any power your system generates is used by the loads of your house first. If you aren’t using the full output of your array, the excess power is fed into the grid system of the power company.
Each local power company has its own way of “buying” your excess power, ranging from letting your meter “run backward,” or “net metering” (that uses two meters, one showing how much you’ve used of the power company’s power, and how much your system has pumped into the power company’s system—with the difference between the two used to figure your bill), or using the second meter to figure how much your system has pumped into the grid, but paying you for that at a rate different than what you pay for the power company’s energy.
One kilowatt (also expressed as 1,000 watts or 1 kW) is probably the smallest system that economically should be installed. Multiples of 1 kW are easily added, normally to about 5 kW for single family residences.
This simple grid intertie system needs only occasional maintenance in the form of washing off the PV modules. Normally Mother Nature’s rainfall will keep them clean. The homeowner may also have to look at the inverter’s panel to see if there are red lights or other signals telling if the inverter may not be working. Those signs may trigger a call to your friendly PV technician.
Falling leaves need to be kept off the array. Any blockage wipes out a PV cell’s ability to generate electricity—and is the enemy of generating green electrons!
—the granddaddy of the industry and most commonly found and most efficient (about 15%) of the materials used in today’s PV modules. Efficiency? Look at it this way: If 1,000 watts of sunlight falls on 1 square meter of crystalline silicon PV modules, about 150 watts—or 15%—of electrical energy is produced.