Wednesday, January 25, 2012

Agriculture or electricity, for Tasmania?

This discussion (below) is copied from a newsletter a friend of mine writes, called Crikey dot Ken. Ken is always on the ball about issues Tasmanian and especially those relating to the D'Entrecasteaux Channel.

I don't know enough about Tasmanian soil to make a good judgement but I do know that the area being discussed for this irrigation scheme is prone to drought, and that is why it is cheap land, while many parts of Tasmania have excellent rainfall.

I should explain that Tasmania has well established hydro-electric schemes and some new wind farms. It is in an ideal position to make all its own electricity if it manages these well and invests in innovative mini-hydro farms like this one. Its only other option is to pump electricity across Bass Strait from the mainland, at huge cost, which it has started doing, much to the annoyance of customers like me who are seeing their costs double!!

One wonders what is really behind all this; one thing is for sure - it is about money and politics, and not about what is good for the future.

An agricultural bonanza for Tasmania or just a few others?

There is something not quite right with the scheme to bring water for irrigation to the midlands of Tasmania from Arthurs Lake. A motherhood question would be, ‘Are you in favour of an irrigation scheme that would see productive farms producing food that would feed many thousands if not millions of people in Australia and across the world’? This political proposal is to pipe / drain water from Arthurs Lake in the Central Highlands to the lower cost land illustrated in the map to the right. It’s an engineer’s dream job.

image But what are the cons apart from the pros? Arthurs Lake is a good size lake that sits below the much bigger Great Lake of Tasmania. The pros of Arthurs Lake is it has a catchment while the higher, bigger Great Lake has virtually no catchment apart from direct rain and snow. The Great Lake, last ten or twenty years, has been at the best say variable. The level of the Great Lake over the last twenty or more years has been bordering on empty most of that time. Traditionally the method has been to pump the Arthurs Lake water up to the Great Lake in the off peak and then funnel it down via Poatina Power Station which has been believed to produce the most efficient power generated in Tasmania such is the fall of the water. It has six turbines, with a combined generating capacity of 300 MW of electricity. There is a net gain to Tasmania using Arthurs water.

So who are the winners and the losers?

Now we are told Hydro Tasmania are being asked / told to for-go that water from the Arthurs Lake to feed the new Tasmanian Midlands Irrigation Scheme. If there has been modelling as to how much water is required for Irrigation; what is that amount? Does it equate to the water forgone by Hydro Tasmania for electricity generation? If the irrigation authority get it wrong with their estimates being on the low side of irrigation water required, will it be just as easy, or even easier, to take water out of the Great Lake too via Arthurs by reversing the past usual process?

As the Great Lake is likely to experience even lower precipitation and snow in the future will that mean that the most efficient power producer in Tasmania, Poatina, will be idle more times than not for lack of water that is drifting down a pipe line to the midlands to produce food and wool in a much less efficient way than Hydro Tasmania creating good clean electricity that is destined to fetch astronomical prices on future mainland markets. The infrastructure is already there to produce electricity.

The irrigation scheme will cost 100 million dollars for a harder to earn, unknown return This is more a shift of money from the electricity uses of Tasmania to the pockets of a few wealthy investors and some hard working farmers. In hindsight, all will be left is a few trout fishers looking at the mud of Arthurs and the Great Lake much like the older anglers reminisce about the great days of the Shannon Rise. This could be one of the greatest shift of capital from the Tassie battlers to the corporate board room, ever, and that’s saying something.

Thanks Ken for allowing me to put this on my blog.

1 comment:

Paulette Whitney, Provenance Growers said...

This scheme concerns me from a biodiversity perspective. Tasmania's Midlands boast wonderful, diverse grasslands which can thrive under carefully managed grazing. If this area is irrigated and put under huge cropping monocultures, the incredible flora and fauna that depend on this type of landscape will disappear. And that's without going into salinity, soil degradation, run-off of fertilisers and other agricultural inputs....Thanks for bringing it up Kate.