Disruptive advances in solar technology are unusual, with industry-wide design improvements often taking place in very small increments. These small changes create the buzz at solar trade shows like Intersolar North America, which is wrapping up this week in San Diego. However, one standout concept on display here is the Intensifying Solar Panel, a low concentrating solar device that includes its own internal tracker, now four years in development. The company reckons it can deliver the panels at roughly half the cost of a standard solar panel, thanks to a variety of technology improvements.
The conic mirrored aluminum reflector waves of the panel manage to boost cell efficiency 20× through the concentrated light, which strikes a trough of sliced silicon cells that represent only 5% of the volume or area of a traditional crystal silicon panel, according to the co-inventor, Suneet Singh, also the co-founder of Innovative Solar Power, based in Montreal.
The ISP panels use single junction monocrystalline silicon deployed as arrays, with patent-pending processes that deliver efficiency close to multi junction cells, Singh says. The design includes a large bus conductor attached to the solar cells using a multi-layer deposition method that reduces loss due to resistance.
While concentrating solar is an old concept, ISP Solar has cleverly added a tracker function by linking the mirrored aluminum cone waves with a wire that is driven by a small motor that serves only that panel. The entire panel is encapsulated to avoid soiling, and includes an aluminum base sheet that serves as a heat sink, ensuring that the cells will not overheat and lose light conversion efficiency.
The 85 watt panels operate with a cell efficiency of 24.3%, based on 1,500 volt wiring. The panels are rated for operation between -40 Celsius to 85°C, suggesting that the panel can be readily used in northern climes where such low temperatures could paralyze standard solar panels. The panels can withstand a snow load of 5,400 Pascal — or about 113 pounds per square foot, and a wind load of 2,400 PA — or about 140 miles per hour, Singh claims.
Among the design elements the company has made to boost the panel efficiency is a tracking system that can reposition in five minute increments. The motors used to drive the tracker are off-the-shelf units rated for eight hours of continuous operation at full speed for 50 years; the tracker requires only a low speed from the unit, Singh points out.
Although the panel weighs more than a standard crystal silicon solar panel, the internal tracking mechanism weighs only a small fraction of what standard single-axis tracking racking does. As a result of the internal tracking, the ISP system can be mounted on a fixed support system, which is typically the lowest cost capital investment for a solar array.
The ISP Solar panel also can be mounted on a commercial or industrial rooftop, on carports, or other structures where trackers generally are not feasible because of their massive weight. Tracking solar designs command the utility-scale solar market, but require open, near-flat spaces that are near power line interconnections. With the advent of the low-concentrating solar panel, the added efficiency of a single-axis tracker — typically around 15% — now may also be shared with commercial and industrial customers.
The company has three demonstration sites under evaluation in Canada since August, and is working to engage the National Renewable Energy Laboratory (NREL) in Golden, Colorado, to test the device as well. The company hopes to be able to begin manufacturing by the end of the year.
The ISP modules come with a 25-year performance and equipment guarantee that will be backed by third-party insurance, which helps assure customers that the warranty will endure.
Concentrating photovoltaics (CPV) has been on the design tables of solar companies for decades. Cumulative CPV installations reached 350 megawatts in 2016, less than 0.2% of the global installed capacity at the time, Wikipedia notes. CPV installations are located in Canada, China, the United States, South Africa, Italy and Spain, among other sites.
One early proponent of CPV in the United States was the Advanced Research Projects Agency within the US Department of Energy (DOE). ARPA-E provided R&D funding in 2015 for the MOSAIC Program (Microscale Optimized Solar-cell Arrays with Integrated Concentration) to further combat the location and expense challenges of existing CPV technology. The program ended in 2019
The MOSAIC program was ambitious in its effort to create a broadly applicable technology. “MOSAIC projects are grouped into three categories: complete systems that cost effectively integrate micro-CPV for regions such as sunny areas of the U.S. southwest that have high Direct Normal Irradiance (DNI) solar radiation; complete systems that apply to regions, such as areas of the U.S. Northeast and Midwest, that have low DNI solar radiation or high diffuse solar radiation; and concepts that seek partial solutions to technology challenges,” the program description noted.
The goal of the MOSAIC program was simple, yet vast: “If successful, these technologies could facilitate cost-effective deployment of solar power systems across a wide range of geographical locations, lowering U.S. greenhouse gas emissions and reducing dependence on imported energy.”