Vycházím z blogu šéfové výzkumu té firmy (mimochodem,zahájení PhD v sedmnácti na Princetonu na katedře fyziky plazmatu, klobouk dolu) http://www.lightsail.com/blog/making-economical-cl ean-energy-at-planet-scale/ tak těch 70% je Grid-Grid účinnost

The efficiency that we think that we can hit, eventually, it should be theoretically possible, is 70% plus. But with our first product we think we can hit between 60-70%. We’ve done a lot of work on this. With the help of our first investor, Vinod Khosla, we managed to build an industrial scale proof of principle.