Aurelia Turbines and hydrogen

Aurelia Turbines develop and produce small gas turbines which can operate on a range of fuels. One of these fuels is hydrogen.

Why hydrogen?

  • Hydrogen is clean, as complete combustion results only in water.
  • It can be produced using renewable energy.
  • It can be stored and used only when needed.
  • Hydrogen can be used to decarbonize the sectors where a shift to electricity is not an option. Those sectors range from food production, where steam is needed to steel, cement and chemicals, where the industrial process requires heat of more than 1,000 degrees Celsius.
  • To a limited extent, it can be fed into existing natural gas pipeline systems. This reduces the need to build new infrastructure for energy delivery.

What are the challenges with hydrogen?

  • Hydrogen-containing gases lead to combustion speeds that are too high for conventional gas turbines. For example, if pure hydrogen was used with normal natural gas fuel nozzles in a turbine, the nozzles would melt as the combustion would occur prematurely.
  • Hydrogen gas is highly reactive and therefore has a very high laminar burning velocity. Hydrogen combustion is approximately ten times quicker than that of other fuels. This may lead to hydrogen causing explosions if it is not handled properly.
  • Even though hydrogen has good energy density by weight, it has poor energy density by volume versus hydrocarbons. For example, the volumetric energy density of hydrogen is 3.2 times less than that of methane.
  • Hydrogen can enter and diffuse through steel even at room temperature. It can embrittle steel, causing the rigidity of the steel to weaken. This, combined with the requirement to withstand high pressures, makes many ordinary steel structures unfit for storing hydrogen.
  • Component gases in industrialised sources make hydrogen more difficult to utilise.

Why can Aurelia use hydrogen?

  • The structure of a gas turbine is different to that of a reciprocating engine. While some amount of damage in a piston engine is unavoidable, high burning velocity does not harm a well-designed turbine.
  • Aurelia achieves fuel flexibility by a modular design. The combustor is designed as a separate component from the turbo machinery. Physical changes in the combustion chamber – such as adjusting the length, volume or internal air flows – do not affect the rest of the turbine. Consequently, with a relatively small number of changes, hydrogen can be utilised to generate electricity using Aurelia’s two-spool, intercooled and recuperated (IRG2) gas turbine process.