Thermo chemical - Solar gas
CSIRO is working on heating methane CH4 in a solar thermal tower to break it down to H2 and CO2. The idea is to bury the CO2 and pipe the hydrogen with more energy than the CH4. The energy gain is from the solar heat.
When the H2 burns the heat will be released. Otherwise it will generate electricity in a fuel cell.
It would work well with a solar thermal plant that uses gas (methane) as a backup. During the day the gas could be converted to Hydrogen rich gas.
SolarGasTM is now ready for commercial use.
The solar tower and heliostat field at CSIRO's National Energy Centre in Newcastle, New South Wales.