Coal Seam Gas

Coal seam gas (CSG) is one of the highest quality and cleanest forms of thermal energy in the world, typically comprising less than 2% CO2 and about 95% methane. Because of this, it produces less greenhouse gas emissions than conventional natural gas, which can contain up to 50% CO2 when brought to the surface. CSG's significant potential is being recognised around the world — it already provides 15% of the USA's gas supply and close to 90% in Queensland, Australia.

CSG and underground coal gasification (UCG) both harvest energy without removing coal from the ground, but there are important differences between CSG and UCG.

 Coal seam gas flare, Waikato

Why CSG?

It is another form of indigenous natural gas that can offset the declining production of New Zealand's Maui gas field.

  • The small wells do not disrupt existing land use, making it easy for farmers to supplement their business income with CSG royalties.
  • It creates fewer greenhouse emissions than any other thermal energy.
  • It supports distributed generation by contributing electricity to the national grid from multiple points around the country, potentially avoiding expensive transmission upgrades.
  • Electricity from CSG would provide base load generation to support further renewable electricity generation projects.

How does it work?

When coal forms in the ground, the associated chemical and biological processes produce methane gasses. This methane sticks to the coal surface and stays in place because of the high underground pressure within the coal seam. By pumping water out of the coal seam, we can lower that pressure so the gas is released and then channel it to the surface for electricity generation or heating.

What are we doing?

Solid Energy is successfully continuing CSG exploration and resource proving in our Huntly field in the Waikato, and the Tahora-Tangarakau area in Taranaki. Exploration is most advanced in the Waikato, where test wells have yielded high quality gas containing 98% methane and just 1% CO2. Exploration is continuing across all these sites.