Tandem Sun employs the most efficient solar harvesting technology available today – multi-junction solar cells (MJSCs). MJSCs currently have a proven efficiency of over 43%, but high cost restricts their use. Tandem Sun has therefore developed a unique patent-pending technology able to cut the costs of MJSCs while at the same time increasing their efficiency. The company believes that MJSC technology can now achieve Grid Parity at utility scale and, in a longer perspective, in rooftop applications.