Equipment and products that enable us to use renewable energy instead of fossil fuels and conventional electricity are highly beneficial. Examples include solar thermal systems, solar electric (photovoltaic) systems, and wind turbines. Other power generation equipment, such as fuel cells and some energy storage systems (like batteries) are included here because they help us accommodate varied energy sources so that we may eventually move beyond fossil-fuel dependence.
Ready Solar manufacturers Solar in a Box, a pre-engineered and pre-assembled residential solar electric system. Partnering with inverter manufacturer KACO Solar and panel manufacturer Sharp Electronics, Ready Solar combines the framing system, panel and inverter into one low-profile unit. The inverter converts low-voltage DC to AC at each panel, eliminating the need for a central inverter and DC disconnect. If one unit fails or becomes partially shaded, the rest of the system continues to operate at full capacity. In the event of failure, a panel-level, web-based monitor sends an alert. System monitoring is provided for 5 years at no cost to the owner. Solar in a Box has a 25-year warranty on the panels and a 15-year warranty on the inverters.
Choose a photovoltaic (PV) system to fit your energy needs, budget, and the space you have for installing the modules.
Crystalline modules are proven, efficient, and reliable, and produce the most power per square foot, especially during peak hours. You can get these as mono- or polycrystalline products and the lesser-known ribbon technology. They don’t work well on cloudy days or in high heat, however.
Monocrystalline modules are the most efficient rooftop mounted systems, with some modules reaching 20% efficiency. So if you don’t have much space for a PV installation or want maximum power production, these are a good choice. Polycrystalline modules are almost as efficient as monocrystalline, and they are less expensive, so these are a good option for those on a tighter budget or with a little more space for the modules. Thin-film PV is less efficient than crystalline, and less expensive, too.
Thin-film works well in low-light conditions and in high temperatures so over the course of a year can create more power than crystalline PV per rated capacity, but because the rating capacity is lower for the same area, you’ll need a lot more room on the rooftop to have that much capacity. Amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium selenide (CIS)/copper indium gallium selenide (CIGS) are the major technologies.
GreenSpec lists PV modules that have high warranted minimum power ratings—the amount of power the company guarantees the module will produce—and high PTC (PVUsa test conditions) efficiency ratings, which are considered more of a “real world” representation of performance. PTC ratings are used by the California Energy Commission to determine rebates and are usually several points lower than the STC (standard test conditions) ratings.
Ratings and Commentary