Hitachi Zosen Inova’s power-to-gas technologies are designed to make renewable energy from volatile sources of electricity storable and to decarbonise energy and industrial systems.

Power-to-gas technology is an integral component of today’s energy business and cutting-edge infrastructure. We provide turnkey plants that can be combined with existing WtE and biogas installations or other electricity and industrial COproducers, enhancing overall plant efficiency and directly boosting economic efficiency.

With the EtoGas technologies of alkaline pressure electrolysis and catalytic methanation as well as a biological methanation from Schmack, we offer clients seeking to generate synthetic gases such as hydrogen and methane for use as energy carriers, alternative fuels or in industrial applications suitable processes to choose from. As experts in the construction of thermal and biological energy recovery plants, we’re familiar with the processes both up- and downstream of power-to-gas installations. We also have our own production facilities, enabling us to deliver individual designs tailored to specific customer needs and requirements.

Technology and Services

With electricity production so volatile and prices in decline, operators of waste treatment and industrial plants, and energy producers with access to cheap green power, are looking for alternatives to be able to run their installations profitably. One cost-efficient solution is alkaline pressure electrolysis.

Electricity is input into the process to produce oxygen and hydrogen. These are separated by electrolysis, with the 5.0 quality hydrogen then compressed to 200 or 500 bar for trailers. The hydrogen can be used in industry or as a vehicle fuel, or alternatively it can be fed into the natural gas grid as a store of energy.

Alkaline pressure electrolysis EPC plant is available in 2 MW modules and can be scaled as required.

Image: INPEX Anlage, Japan

All over the world countries and regions are working on strategies to decarbonise the economy and society at large. Companies are also looking for ways of reducing carbon emissions and intelligently feeding them back into the energy cycle. This is where catalytic methanation, one of the technologies in HZI’s EtoGas portfolio, comes in.

The inputs for this process are hydrogen, for example from electrolysis, and gases containing COsuch as biogas, exhaust gases or industrial syngas. In a catalytic reaction, carbon dioxide and hydrogen react on the surface of the catalyst surface to produce water and methane. Using catalytic methanation to decarbonise industrial plants is a cost-efficient CO or COreduction option. It’s a sustainable process that enhances both the lifetime and overall efficiency of a plant.

Installations are available in sizes from 8 to 500 mof product gas per hour.

Designed, co-funded and constructed by HZI, the INPEX plant in Japan is an impressive reference and a perfect example of where the path to sustainable energy will lead.


BiON® power-to-gas technology is a compelling biological methanation method using electricity to produce synthetic methane.

The main agents in this anaerobic process for converting hydrogen and carbon dioxide into pure methane are special microorganisms called archaea. Ambient pressure and temperature play a special role in all this. The purity of the source gases, by contrast, does not have to be high. The carbon dioxide (CO) required for the process is used as it comes, regardless of whether it originates from industrial processes, the ambient air or fermentation plants. The synthetic methane produced is fed directly into the natural gas grid, stored in a gas storage facility or alternatively used as required to support a combined heat and power plant. This biological power-to-gas technology is thus fundamentally different in technical terms from the chemical/catalytic process.

HZI Schmack offers you the entire range of technological know-how, from engineering and plant construction to service, on a one-stop basis.

Image: Power-to-gas plant on the Limeco site in Dietikon, Zurich

INPEX plant, Japan