Energy Efficiency

The reality is that governments know we are headed for tough energy poor times; its not just the exploding population growth, the reduced available fresh water, the fact we import more and more food every year because we can no longer grow it; it’s because the cheapest form of energy is being frittered away.

Like an ignorant teenager, they want to continue to party like there is no tomorrow, they want to have as good a time as possible and let tomorrow take care of itself.

Trouble is, there are no technoloigical saviours; of course they want to appear to be in control and advocate many wild and woolly plans to get that energy from somewhere.

They spend the public’s money like it belongs to someone else and increasingly encourage the public to support the next ‘big thing’.

Media tart Peter Beattie spent some $300 million on – an American company – shale oil plant even though he was told it wouldn’t work and Queelnsland’s Labor party pulls dead rabbits out its hat with increasingly less conviction.

So what have Australia going for it ? Why solar power, but its the least funded and supported source of energy and you have to ask why; could the answer be as simple as the egos of bureaucrats not wanting to be proved wrong ?

No, they decided that getting energy from the Sun was not as good as geothermal energy, and pumped millions of $’s into the scheme and invited a gullible public to follow suit (it worked with Telstra didn’t it ?).

A document (pages 3-6) of the Geodynamics Annual Report for 2009 had an interesting snippet;

Extraction of geothermal heat demonstrated.  

Flow testing has demonstrated production of geothermal energy from hot rocks with a peak production of 40 kg/sec.

Dave Kimble did some calculations and arrived at a less than satisfactory EROEI (Energy Rurn on Energy Invested) …

Presuming that means 40 kilograms of pressurised hot water ( 225°C ? ) brought to the surface per second; the rate of excess heat above the ambient temperature ( 25°C ) would be 40,000 x ( 225 – 25 ) x 4.18 = 33,440,000 watts

In fact that heat is put through a heat exchanger and heats isopentane which boils and goes through the turbine in a closed loop and produces electricity . Since they were going to produce 1 MW before the system blew up and was abandoned, the efficiency of the hot water to electricity conversion process was only 3%, which is incredibly low.

And that is their peak figure – you would expect that as they suck the heat out of the rocks, the rocks would cool and over time the temperature of the hot water would fall.

The heat is replenished by heat flowing in from surrounding rocks, but the thermal conductivity of rock is not all that good, so as the distance the heat has to travel through rock to get to the circulating water gets longer, the slower the heat will pass, and the more the circulating water’s temperature would fall. This rate of fall of temperature is a critical figure for the geothermal process and it is amazing that they haven’t been crowing about how good it is as a result of the trials. The implication is that the figure is not so good.