Green Hydrogen
Clean, reliable and secure energy supply is a key requirement for the further development of the European economy. At the same time, the Paris Agreement and its aim to limit the global warming to well below 2°C call for a quick and significant reduction of CO2 emissions, including the energy sector. In the energy sector this can only be achieved by a significant increase of the share of renewable energy sources (RES). As the most abundant RES, wind and solar, are intermittent by nature, there is a need for energy storage technologies, to provide back-up power when wind and solar output are low and more generally for load levelling and grid stabilisation.
Chemical storage appears to be the most promising long-term energy storage technology. Among chemical storage technologies, hydrogen is expected to dominate as it can be produced by electrolysis of water using excess energy from RES, easily compressed and stored, and finally re-electrified using gas turbines.
Siemens vision for energy
e-Hydrogen is the generation of Hydrogen through electrolysis of water.
The Role of the Gas Turbine
Siemens are currently modifying existing Small Gas Turbine Combustor technology to burn both Natural Gas and Hydrogen for fuel. These Hydrogen and Natural Gas Co-firing Gas Turbines will be able to run on any ratio mixture of Hydrogen and Natural gas, with the desired proportion being solely hydrogen. Natural Gas stores ideally would be used for redundancy or emergency purposes.
Emissions & Closed Cycle
(Civils if you’ve made it this far, cheers)
The combustion of Hydrogen in pure oxygen yields water as the only waste product, as follows:
This means theoretically the only exhaust products out of the Gas Turbine will be steam, therefore the intention is to turn the engine into what is known as a closed cycle. Whereby the exhaust steam is condensed to water, and fed back into storage for subsequent electrolysis into hydrogen and oxygen.
The reality is that combustion of Hydrogen in Air will additionally yield oxides of nitrogen – bad. This will drive development of more robust catalytic converters to strip oxides of Nitrogen out of the exhaust.
Further Reading
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