Liquid Petroleum Gas and the Crib Point Installation
The proposal, as most people on this side of the Peninsula know, is to import liquefied petroleum gas, to convert it to gas vapour at a complex installation, and send it up a pipeline to Cranbourne. It all seems pretty simple and harmless.
Let’s have a look at how this is going to happen. The gas will arrive as a liquid at -163degrees C in large ships somewhat like an oil tanker and a port facility to “gassify” the LPG will be built for this process.. This will involve the removal of some of the shoreline vegetation at Crib Point.
The gas arrives in these tankers as liquid at 163 degrees below zero.
To get the liquid gas to where it has to go it has to be volatilised, or converted to a gas (vapour) rather than as a compressed liquid. To do this AGL are proposing to use sea water to warm the liquid gas to “boil it” so it can flow up the pipe to Cranbourne. This means that sea water from Western Port will be used to warm up the LP gas. The sea water expelled back to Western Port will for most of the process be about 5-7 degrees less than when it went in. Additionally the water will be chlorinated so that marine organisms sucked into the system will not foul the pipes and filters. This process results in complex toxic organo-chlorine complexes. They will be released with the chilled water back into Western Port Bay.
Western Port is a RAMSAR nominated environment. It has Bass Strait as open ocean to its south with seals and fairy penguins (both important tourist destinations) and mud flats and mangroves up to the north. Western Port alternates environmentally with saline environments as the tides ebb and flow. The mangroves and mudflats are one of the breeding grounds making up the beginnings of the fish populations and other organisms that support the biodiversity of Western Port and the migratory sea birds that live here or migrate here. These contribute to the fishing potential of the seals, penguins and the southern oceans.
The idea of releasing mega litres of sea water (468,000 cubic meters or 468,000,000 litres) per day at 5 to 7 degrees less than ambient during this process is an experiment of huge proportions with outcomes that cannot be positively predicted. It is a figure that defies comprehension, to think of it again: 468 million litres each day. The result of the large scale warming of the liquid gas to volatilize and the cooling that will have on sea water will have far reaching effects and long term effects on the marine ecosystems of Western Port’s planktonic, benthic environments and the tidal mudflats. That amount of chilled water cannot be insignificant. It will probably have an effect on the commercial mussel farm close to Flinders. We have no information on the effect of organo-chlorinated residues and a cold water plume in the ecosystem or the effect on fishing, sea birds, seals penguins or anything else.
You might think that this will not have much effect on things. Let me give an example of something major that happened many, many years ago when the sewage outfall started at Boag’s Rocks near Gunnamatta. This changed the salinity of the sea water from 36mg/l down to 21mg/l. The plume of diluted sea water moves easterly and is diverted somewhat out to sea by Cape Schanck. This change is salinity has dramatically changed the marine environment at Cape Schanck; all the big kelps are gone for example. It will come around West Head and modify this end of Western Port. Do we really have the right to alter the natural environment at Crib Point or anywhere else??
Formerly Assoc. Prof. School of Biological Sciences, Monash University Clayton