The industrialization of the electrochemical reduction of CO2 toward CO in aqueous electrolytes has recently been started using silver-based gas diffusion electrodes. The performance of a CO2-to-CO electrolyzer model on a 10-cm(2) cell size is assessed with respect to operating pressure, achievable current density at faradaic efficiency of CO above 90 %, composition of gas streams and operational lifetime. Operational lifetime has exceeded 1500 h. The first scaling step to 300 cm(2) has been accomplished. The rated power of such a cell is around 300 W.

In this work, the exothermic reaction of the chemical energy storage material for stranded renewable energy, lithium is analyzed in carbon dioxide (CO 2 ) and air. Spectroscopic techniques were used to characterize the reaction of bulk lithium pellets of up to 1 g weight. In comparison, power plant applicable combustion of atomized lithium spray was analyzed. Electrical high voltage spark was used to overcome to activation energy of the combustion for the experiments with bulk lithium. The lithium spray was successfully ignited by pre-heating the reaction gases (air and CO 2 ). Radiation temperature of the bulk lithium during reaction in air was calculated to 2260 K. The observed green and red emission of the lithium combustion could be demonstrated in the spectral analysis. In CO 2 atmosphere the reaction products were found to be lithium carbonate with little lithium oxide. Beside, lithium carbide could be detected in the reaction product of the combustion of bulk lithium. The gaseous reaction product carbon monoxide (CO), which could be further converted with hydrogen from renewable sources to valuable methanol or gasoline, was detected online by gas analysis.

In this work, electrochemically recyclable lithium is analyzed as high energy density, large scale storage material for stranded renewable energy in a closed loop. The strongly exothermic reaction of lithium with carbon dioxide (CO2) yields thermal energy directly comparable to the combustion of coal or methane in an oxygen containing atmosphere. The thermal level of the reaction is sufficient for re-electrification in a thermal power plant compatible process. The reaction of single lithium particles, avoiding particle-particle interactions, is compared to the combustion of atomized lithium spray in a CO2 containing atmosphere. Particle temperatures of up to 4000K were found for the reaction of single lithium particles in a CO2, nitrogen (N2), oxygen (O2) and steam gas mixture. Furthermore the combustion of atomized lithium spray in both dry CO2 atmosphere and CO2/steam gas mixture was analyzed. The identified solid reaction products are lithium carbonate, lithium oxide and lithium hydroxide. The formation of carbon monoxide (CO) as gaseous reaction product is demonstrated. Carbon monoxide is a valuable by-product, which could be converted to methanol or gasoline using hydrogen.

In this paper, two different solutions for efficient solar powered sensor networks are presented and compared. Some fundamental considerations on the interaction of the solar cell, the storage capacitors, the DC/DC converters and the wireless radio transmitter are reviewed. The challenges for implementing a direct DC/DC conversion for powering wireless sensor networks are addressed. The realised circuit guaranteed an autonomous start up and a continuous operation of the entire wireless radio transmitter network from an illumination level of above 400 lx. Alternatively, with improved energy storage capability and best possible harvesting of solar power, a two-step DC/DC conversion system was realised. The key component of the supply scheme is a custom designed, low power ASIC which controls the solar cell at the MPP (maximum power point) to guarantee the most efficient use of the available solar power. The realised low power ASIC consumed only 800 nA of DC current to fulfil its control task.