Ken Zweibel

The Impact of Tellurium Supply on Cadmium Telluride Photovoltaics

Better optical designs and enhanced recovery of tellurium may boost the potential for large-scale energy production from thin-film cadmium telluride solar cells. For decades, the material associated with photovoltaic (PV) cells has been silicon. However, after many years of development, cadmium telluride (CdTe) PV modules have become the lowest-cost producer of solar electricity, despite working at lower efficiency than crystalline silicon cells. CdTe sales are growing rapidly, but there is concern about projecting hundredfold increases in power production relative to current production with CdTe PV modules. One reason is that Te, a humble nonmetal that is actually abundant in the universe, is as rare as many of the precious metals recovered from Earths crust (1). Furthermore, current technology now uses Te at rates that are substantial fractions of its supply. Here, I argue that the long-term potential for CdTe PV modules need not be bleak, given realistic developments in module technology and Te recovery.

Centralized Production of Hydrogen using a Coupled Water Electrolyzer-Solar Photovoltaic System

This study investigates the centralized production of hydrogen gas (H2) by electrolysis of water using photovoltaic (PV) electricity. H2 can be used to power all modes of transportation. The logical first large-scale application of H2 is as a replacement fuel for light-duty vehicles, light commercial trucks, and buses. Since H2 is an expensive fuel compared to gasoline, consumer acceptance of H2 is contingent on its use in advanced fuel economy vehicles such as fuel cell vehicles (FCVs), which lowers the cost of H2 relative to the cost of gasoline used by conventional fuel economy vehicles. The purpose of the study is to provide baseline projections of capital investments, levelized H2 prices, and fuel cycle greenhouse gas (GHG) emissions of a centralized PV electrolytic H2 production and distribution system. This is important in order to evaluate the economic and environmental impacts of utilizing PV electrolytic H2 as a fuel source. The use of PV electricity for electrolytic H2 production is a means of storing solar energy and overcoming its limitations as an intermittent power source. However, the intermittency of solar energy reduces the utilization capacity factor of electrolysis plants, which increases H2 production cost. The relevant question is whether the

Multi-gigawatt thin film PV

Thin films are reaching 1-GW annual production because of the success of one company and technology, First Solar CdTe. Other thin films languish, with amorphous and thin film silicon still restrained by low efficiencies; and CIS yet to demonstrate sufficient volume production. Will the future of thin films be only the future of CdTe? Yet even with commercial success, CdTe must also compete with crystalline silicon, which has taken a big step forward with the end of the silicon feedstock problem. What then is the true competitive position of crystalline silicon and CdTe? Still, PV is not alone in providing us with alternative energy. Arguably, the key qualities are non-CO2 production and the potential to make terawatts. PV will compete with solar thermal electric, wind, nuclear, and carbon sequestered fossil fuels to ameliorate the greenhouse effect and energy dependencies. How does PV stack up? And how does intermittency make this competition even harder for PV? One thing is certain, PV costs must continue to drop, because true success in the marketplace will be hard won.