Get ready for the hydrogen economy

Science Centres: Energy

Hydrogen is an attractive option as a source of clean, secure energy, especially for transport. If or when hydrogen vehicles really take off overseas, New Zealand has to have the infrastructure to handle them, including hydrogen production and distribution.

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CRL Energy’s fluidised bed coal gasifier system. (Photo: Alan Blacklock, NIWA)

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Coal to hydrogen process

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CRL Energy technical officer, Ben Rumsey, monitoring operation of the gasifier. (Photo: Alan Blacklock, NIWA)

In a hydrogen economy, New Zealand would need to produce approximately one million tonnes of hydrogen every year to run its transport fleet. Renewable fuels alone are unlikely to meet these volumes. CRL Energy is now working on the final stage of technology to convert New Zealand’s low-rank coal into high purity hydrogen for fuel cells developed by Industrial Research Ltd. This research programme, called Hydrogen Energy for the Future of New Zealand, is funded by the Foundation for Research, Science & Technology (FRST).

Steady progress

The first step in the process requires a fluidised bed coal gasifier – one of three new types of gasification technology developed internationally during the past two decades and the one best suited to New Zealand’s low-rank coals (lignites and sub-bituminous coals). Compared to the other gasification technologies this is a low-temperature process(around 900º C) and the coals must be highly reactive. Our previous research had shown that our coals are among the most reactive in the world.

CRL Energy designed, constructed, and operates a 50 kW fluidised bed gasifier. It produces a syngas comprised mainly of hydrogen, carbon dioxide, and carbon monoxide. The syngas also contains small amounts of hydrogen sulphide which can damage the fuel cell and other components downstream of the gasifier. We overcame this technical challenge about a year ago, successfully removing the hydrogen sulphide to below detection limits (sub parts per billion). This has allowed us to proceed to the next stage in which the syngas passes through a catalyst bed and most of the carbon monoxide is converted to carbon dioxide and hydrogen.

The entire package from gasifier through to shift reactor is now fully integrated and work has begun on the final stage moving from shifted syngas to hydrogen fuel cell. The CO2 is separated at this stage and would have to be sequestered in stable geological formations. Carbon capture and storage is the focus of a new FRST-funded programme involving CRL Energy and is led by GNS Science.

How could New Zealand become a hydrogen economy?

CRL Energy also leads the Transitioning to a Hydrogen Economy research programme. This FRST-funded programme is part of the ‘Energyscape’ suite. It is identifying:

  • a likely pathway to a hydrogen economy in New Zealand
  • the knowledge gaps and barriers to that pathway
  • the research investment that may best fill them.

The project team has circulated an issues document to targeted end-users, describing what a hydrogen economy is, relevant international research, and the potential hydrogen supply chains for New Zealand. Currently the team is identifying the most favoured supply chains. These supply chains will then be used as the basis for scenario development (how might New Zealand get to a hydrogen economy?) and these scenarios will be used to highlight the existing knowledge gaps and barriers. The final report is due by the end of the year.

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