By ERWIN CHLANDA
Turning rubbish into electricity sounds an appealing idea especially as the town council’s present tip – likely to be the town’s biggest polluter – is running our of space.
As it happens a local resident, Paul Darvodelsky, is an expert in process engineering whose consulting business, Pollution Solutions & Designs Pty Ltd has clients throughout South East Asia and Australia.
Mr Darvodelsky also is a film buff and owns the Alice Springs Cinema whose power bill has gone through the roof.
He says, in a nutshell, the town is producing enough garbage to generate electricity for nearly one third of all homes in Alice Springs. This is 10 times more than the Uterne solar power station produces.
Furthermore, it would reduce CO2 emissions generated by the current manner of dumping.
What’s more, rubbish dumped for decades, and waste accumulated in the sewage evaporation ponds next-door, could be suitable to be “mined” as fuel for such a generator.
This would reduce the amount of garbage in the current dump which, as Cr Steve Brown has pointed out, is going to be smack-bang in the middle of Alice Springs as it expands south of the MacDonnell Ranges.
“There is no doubt that some form of energy from waste project would be more expensive than a landfill, but then the benefits are also much greater,” says Mr Darvodelsky (pictured).
Here are his numbers:- Assuming we’re the same as the national average, we produce about one tonne of waste per person annually. That’s 25,000 tonnes per year.
Let’s assume that 60% of this is suitable for energy generation. Added to this could be material in the landfill and sewerage ponds which have accumulated over the years. This gives the potential for about 20,000 tonnes per year of material we could burn for energy.
The average energy value (calorific value) of municipal waste is around 15 to 20 MJ/kg. This means a plant burning 20,000 tonnes a year produces about 300,000 GJ of total energy.
To get an idea of the cost of a plant we need to look at the size. 20,000 tonnes per year would give about two tonnes per hour if the plant runs 24/7.
This is not dissimilar to a number of incineration plants I’ve worked on or visited recently. An incineration plant of about this size was recently built at a cost of $25 million. So let’s use that as a base line price.
Normally the cost of operating and maintaining a plant of this sort would be about 10% of the capital cost per year. This means $2.5 million per year.
Now for the energy: 300,000 GJ going into an energy from waste plant would give roughly 100,000 GJ of electricity. This equates to a three MW generator running 24 hours a day, 365 days a year.
At the current sale rate charged by Power and Water of around 30 cents/kWhr this adds up to $8m worth of power per year.
This is about 10 times the output of the Uterne solar power station near the Road Transport Hall of Fame which claims to generate enough power to supply 270 homes.
So we could supply around 3000 homes and this is about 30% of households in Alice Springs. (The average Alice house uses 8.5 MWhr per year.)
The commercial equation is that we have a total life cycle cost (that’s 20 years, net present value) of about $50 million to build and operate an energy from waste plant.
On the income side is a net present value of $80 million which is clearly bigger than the cost, which of course is a good thing.
However, Power and Water don’t generate electricity at the price they sell at so this must be taken into account in any financial assessment.
A further benefit: The landfill will generate – already generates – roughly one tonne of CO2 for every tonne of waste going into it.
This is the way this is calculated: A tonne of rubbish generates 50 kg of methane, which is 20 times as polluting as CO2.
At the current carbon price of $23 per tonne the 20,000 tonnes are worth $460,000 per year or $4.6m (taking into account time value of money) in carbon credits over 20 years, a potential earning for the council: Putting waste to landfill accumulates some cost!
The current manner of garbage disposal used in Alice Springs is likely the greatest source of greenhouse gases in the community.
If Mr Abbott gets rid of any carbon price then we’re still creating and perpetuating an environmental problem.
“Overall the case for an energy from waste plant looks quite interesting,” says Mr Darvodelsky.
“Certainly something which is deserving of further investigation. But it would be important to engage all stakeholders, particularly Power and Water, to make sure that the best path is taken to help make Alice Springs more sustainable.”
MAIN PHOTO: Copenhagen’s new waste-to-energy plant.
Turning garbage into electricity – option for Alice?
By ERWIN CHLANDA