"It was jubilation. We're extremely empowered and excited that there's been another victory by the NSW community against coal seam gas."

No surprise, perhaps, that anti-CSG protesters had something to celebrate with AGL's decision to throw in the towel on gas exploration and production projects at Gloucester and Camden that would have involved $1 billion or more in spending.

Those comments, though, came from Naomi Hodgson, a campaigner for The Wilderness Society, who joined about 20 anti-CSG protesters on Thursday outside Santos's Narrabri Gas Project – 350 km north-west of Gloucester.

Some 16 protesters have been charged at the Santos' desalination plant works in the past two months, including a 47-year-old grandmother who was sprayed with pepper spray by police  on Monday while locked on to machinery with another woman.

Unless another brave company steps forward, Santos will – once AGL exits its existing Camden field with its 96 operating wells in 2023 – have the unenviable role as the sole remaining torch bearer of CSG in NSW.

In Santos's favour is the fact that the government is more confident about the risks of drilling in the geological structures in the Pilliga than scientists ever were with the Gloucester project.

Stuart Khan, an associate professor in engineering at UNSW, says the plan for 850 wells in the Pilliga also gives the project a greater scale to sort out the problems of salt disposal from the CSG production – hence the desal plant under construction that is now the target of protest.

By comparison, Khan notes that AGL was trying to get away with a plan to use the waste water after dilution for irrigation – or at least until the Environment Protection Authority belatedly blew the whistle on the concept.

Unlike AGL with its diversified retail base, though, Santos is a crippled energy company, about $8.7 billion in net debt and a slumping share price. Some analysts question whether it can survive if oil prices – which help set gas prices – remain below $US30 a barrel.

However, after the resounding success against Metgasco's proposed gas field in the Northern Rivers and now against AGL in Gloucester and south-west Sydney, it's a sure bet where environment groups will next focus their energies.

"It was a David and Goliath win," says Julie Lyford, a former mayor of Gloucester and the chair of Groundswell Gloucester, as her group gathered to celebrate their success on Thursday.

"A lot of support will now go to the Pilliga and Camden to make sure they get the same outcome as Gloucester."