By Scott Bentivegna
I often wondered what was inside the EPV Solar building on Bakers Basin Road. Are they a solar installer? Do they make solar accessories? Maybe they trade solar credits? It turns out I was wrong on some of my guesses; they design, manufacture and market solar modules as well as install complete photovoltaic (PV) systems. Someday, they also hope to trade solar renewable energy certificates (SREC’s). Looking at their Web site, www.epvsolar.com, I found out they produce thin-film photovoltaic modules. Like all photovoltaic modules, these convert sunlight directly into electrical energy. However, instead of creating solar cells by cutting wafers from a large silicon crystal, EPV creates the modules by depositing gases that form a thin film of amorphous silicon directly onto panes of glass. This thin film process is less energy intensive and more economical then traditional panel manufacture methods, plus it requires 100 times less silicon than traditional panels.
Here in Lawrence, few of us have the opportunity to see how solar modules are made. To give The Lawrence Ledger readers a chance to understand how EPV makes these modules, I contacted the company and asked for a tour. Jim Savage, marketing manager for EPV Solar, was kind enough to meet with me and give me a walk through the process at their Robbinsville facility.
We started at the beginning with the glass plates. These arrive at the facility with a tin-oxide coating on one side. The tin-oxide is important since it conducts electricity. The glass edges are ground and the corners rounded to remove any sharp edges. After rinsing, a laser cuts a pattern in the coating forming the basis for an electrical circuit. The plate is then placed in a sealed chamber where silicon precursors like silane gas and other additives are deposited on the plates. Controlling the amount of doping additives allows the operators to fine tune the electrical properties of the module.
After the silane deposition, the panels go back to the laser bench for more laser ablation. A thin layer of aluminum is added by vaporizing a small aluminum target. Then back to the lasers. Workers then bond thin strips of aluminum around the edges to form a busbar. These strips will later be used to collect the electricity from the module. A final layer of non-conducting sealant (laminate) is added along with a back pane of glass. The modules are then heat sealed to protect the innards from exposure to the elements. Once cool, the aluminum strips are connected to electrical leads and the last opening is sealed.
To verify the module will produce the amount of electricity expected, many quality control checks are done throughout the process. The modules are also checked with bright lights to check how much electricity they produce. The solar modules have a stabilization process where they will actually produce more than their rated power for the first few months before stabilizing at the rated power.
Since the plates do not require a metal frame, they are cheaper to produce, require less materials and energy to manufacture, and can be incorporated directly into buildings or structures. Some of the panels uses include: a balcony railing made up of modules, a curtain wall for exterior windows, a decorative and energy producing façade, or a shading skylight or awning. The modules can also be used like traditional solar panels on commercial building rooftops or mounted on poles. Several installations include parking structures where the cars are shielded from the sun while the panels above generate electricity.
Find further information at www.sustainablelawrence.org. Contact Sustainable Lawrence at 609-895-1629 with questions or suggestions for additional eco-tips.

