Dimitri Mignard

Triggering Redox Activity in a Thiophene Compound: Radical Stabilization and Coordination Chemistry

The synthesis, metalation, and redox properties of an acyclic bis(iminothienyl)methene L- are presented. This π-conjugated anion displayed pronounced redox activity, undergoing facile one-electron oxidation to the acyclic, metal-free, neutral radical L. on reaction with FeBr2 . In contrast, the reaction of L- with CuI formed the unique, neutral Cu2 I2 (L. ) complex of a ligand-centered radical, whereas reaction with the stronger oxidant AgBF4 formed the metal-free radical dication L.2+ .

Estimating the capital costs of energy storage technologies for levelling the output of renewable energy sources

In remote areas and islands north and west of Scotland and in many other parts of the world, the high cost of connecting wind farms and other renewable energy converters to the grid may make energy storage an attractive alternative. We estimated the installed capital costs of advanced adiabatic compressed air storage (ACAES), vanadium redox flow cells (VRB) and Li-ion batteries in the range of 0.5–50 MW and 0.7–30 MWh. These costs were all of the order of £1 million per MWh, confirming that they already compared favourably with that of network improvements and connection to mainland. VRB and Li-ion batteries had similar capital costs, with VRB being more competitive at lower power output and higher energy storage. Cost reductions of 30–50% would be required for ACAES to be competitive, which may be achieved by the use of reversible compressors that can also be operated as expanders.

Squaring the circle: Sequestration of CO2 as liquid fuel

Publisher Summary This chapter presents the case for using CO2 as a feedstock to fix electrolytic hydrogen. Advantages include the avoidance of small scale reforming and associated un-recovered CO2 emissions for the production of hydrogen; the possibility for a large penetration of renewable generators of variable output into the electricity grid; and the production of clean fuel utilizing CO2 emissions. A preliminary analysis based on integrated heat balances indicates that the methanol-to-gasoline process uses less energy than the production of methanol or ethanol fuel. The Methanol to gasoline (MTG) process seemed to need no net heat input, due to its integration with the methanol process, and reduced distillation loads. In all cases, the extraction of CO2 using amine technology was not considered and would require 10.95 kWh/kmol (CO2+ H2) feed. Future work will look at the integration of this scheme with a fossil-fuel power technology requiring the less energy for CO2 extraction, in particular the chemical looping process.