  STEP (Solar Thermal Electrochemical Production) is an alternative solar
energy conversion process. New and original, unpublished STEP results are
compared with other STEP results. The STEP process uses semiconductors, solar
energy and electrochemistry to generate a wide range of useful chemicals,
rather than electricity, as the product. Using both subgap (to generate heat)
and super bandgap (to generate electrons) insolation, STEP is more efficient
than either photovoltaic or photoelectochemical solar energy conversion. STEP
theory is derived and experimentally verified for the electrosynthesis of
energetic molecules at high solar energy efficiency. In STEP the efficient
formation of metals, fuels, chlorine, and carbon capture is driven by solar
thermal heated electrolyses occuring at voltage below that of the room
temperature energy stored in the products. As one example, CO2 is reduced to
either fuels, or storable carbon, at solar efficiency over 50% due to a synergy
of efficient solar thermal absorption and electrochemical conversion at high
temperature and reactant concentration. CO2 is efficiently transformed to
carbon nanotubes (C2CNT) with or without solar energy. New results on CO2-free
STEP ammonia, iron and cement production are delineated. Water is efficiently
split to H2 by molten electrolysis. A pathway is provided for the STEP decrease
of atmospheric CO2 levels to pre-industial levels in 10 years.
