Here's another energy philosophy; what works is already doing so and what doesn't yet work is pure speculation. Some critical factors are overlooked with granite geothermal. First is the low thermodynamic efficiency with a temperature difference of say 200C, less than half that of other thermal plant. Each time a hole is drilled into the granite to find a new hot spot or because a water channel isn't working that incurs a large energy debt equivalent to hundreds of kilowatt hours. Budget on at least half a million dollars per kilometre for high voltage direct current transmission lines in the outback. Note also the wet froth from these drill holes contains hazardous radon from uranium in the granite. Therefore the water has to be in a closed cycle. In fact the heat flux from hot granite is minuscule compared to solar radiation on the surface. It would probably be easier to store solar energy overnight and bring the facilities a lot closer to town.

I'd give this geothermal revolution a couple of years to prove itself then look elsewhere. Ironically it's kind of the reverse of that other furphy, geosequestration of coal emissions.

Development of hot-rock power generation is already proceeding. There is no need for a change to the economic rules to support it.

The idea of adding solar heaters to make the resource last longer is nothing more a thinly veiled attempt to make solar power look more viable than it is. Making the resource last longer is almost worthless from an economic standpoint.

We have no viable way of storing energy, so our options for exporting energy generated from hot-rocks is limited to those markets that could be reached economically by power transmission line. It's likely that there are none.

The value of tagged money depends on the demand for it. It's simplistic to suggest that there would be no cost to the initial recipient of the tagged money, because they would probably find that they had to sell it at a discount, there being insufficient demand for investment in renewables on anything like the scale required.

These ‘hot rocks’ are part of the natural environment. I wonder if anyone has looked into the consequences of human fiddling with this ‘resource’.

According to the CSIRO’s Peter Metabe, the world will be dependent on fossil fuels for at least the next 20 years.

Oil, gas and coal currently supply 86% of the world’s energy; wind, solar and geo-thermal less than 1/%.

Even if the energy options could be increased by 10 to 20 times (how long would that take?), renewable energy will never meet the growing demand.

And yet, people like Green Senator Milne say that we can switch to renewable energy now for all our needs!

Amazing how Mr Right (aptly named I think) can pour doubt on anything that might cause change. It seems he's quite nervous about change.

And Sylvia, on solar energy, I think you'll find that there are now batteries that store store power reasonably well and that this technology is only improving. In fact, one look at California and you'll find Australian solar thermal technology providing very large inputs to (I think) San Diego, if memory serves correctly, about 15%.

In Perth, where I am lucky to live, we have plenty of hot rocks in the perfect places to provide geothermal energy for the city, plenty of sunshine to utilise solar-thermal, and a regular wind source in summer when energy usage is highest. Add to that a trial of tidal power off Fremantle and it is clear that our reliance on coal and gas could be hugely reduced if the will was there along with only a fraction of the investment currently given to older and less efficient technologies. And even wth gas, the use of combined heat power stations would reduce the waste of power that our current technologies allow, particualarly coal-fired power stations. This is technology that was used over 100 years ago and was lost with the advent of coal, and yet it works far better. Check out what Woking Council did in the UK. They ended up selling power into the grid.

Nay-sayers about these new technologies are simply clinging on to what they know, petrified of change, and unable to show any innovation themselves.

"These ‘hot rocks’ are part of the natural environment. I wonder if anyone has looked into the consequences of human fiddling with this ‘resource’."

The irony is that the only way anyone will find out is if they try it! And they probably won't know for decades if in fact it does make a change.

Basically, the worst that can happen is that the granite rocks will cool down. Whether that will affect us on the surface of the planet is a moot point. Most unlikely I would think.

The biggest problem is likely to be the degree of fracturing of the granite. If it's too great, the injected water turns to steam, escapes down the cracks and is lost to the circulation process. This would kill the idea quicker than anything else.

Phil,

I think you'll find that the battery technology is still at a point where it could not conceivable be used as a way of transporting the energy output from a power station. The highest energy density battery I can find is Lithium Ion, at about 160kWh per tonne. That is, a one tonne battery stores energy worth about $10 wholesale. The output from a 100MW power station would require the movement of 15,000 tonnes of battery per day to the destination market. This is completely outside the realms of plausibility, and nothing short of a couple of orders of magnitude improvement in batteries (not going to happen in our lifetime, and probably never) would change that.

There's no question that things like solar thermal power generators can be built, and they do get built when normal economic rules are ignored(i.e., they're subsidised by governments, either directly with cash, or indirectly with "renewable energy certificates"). Their cost can even be (and usually is) fudged downwards by discounting the capacity required elsewhere in the system to deal with periods of overcast weather. But in any case, attaching one to a hot-rocks generator would make no commercial sense, because it would provide no return at all on investment until the hot-rock resource would otherwise be depleted. Since that would be decades away the net present value of the future return would be next to nothing.

Ah Sylvia,

Who suggested attaching a solar thermal generator to a hot-rocks source?

The point is that if human beings had agreed that we would never get to the moon, we would never have got there because nobody would have tried. So an 'it will never work' attitude doesn't really get us anywhere does it? The same could have been said of many technological advancements. I'm sure battery storage will increase. And there are so many other available technologies to use and develop.

The point of building new systems and testing new ideas, is that while they may not be viable currently, they will never be viable unless they are trialled and further developed. Coal power stations, steam engines, nuclear power plants, the internal combustion engine all went through long development stages and have continued to be developed to this point. And history tells us that people said 'it will never work, let's continue riding horses and burning wood!' Closer to home, piping water from Perth to Kalgoorlie was never going to work either!

BTW I note that you didn't respond regarding combined heat power stations...these are far more efficient than the conventional coal and gas power systems. Just shows that with a little vision and a willingess to invest, you can make things happen.

A basic economics concept is opportunity cost - to be viable, the risk-adjusted rate of return must be at least equal to the best return on alternative investments. Geothermal would be in use now if it were viable; unless, for example, it is not viable only because the pollution costs of other sources are not priced. If, e.g., the effective cost to the community of CO2 emissions is $20/tonne, this could be corrected either by imposing a carbon tax or by a compensatory subsidy to geothermal production. That doesn't require any "new" economics. If geothermal isn't viable on that basis, at current and projected prices, then it's not in our interests to pursue it. Of course, changes in relative prices (cf the rapid rise in oil prices) might make it viable in future, subject to the various reservations voiced in other posts.

These hot rock power sites are, of course, another example of nuclear power (what do you think makes the rocks hot?), and presumably will be rejected by the greenies on the basis that nothing that can be f use may be approved. It's all hot air as far as I am concerned.

As far as I have read, the Hot rocks system has yet to even achieve energy neutrality, and even if it is, the huge volume of water consumed is still likely to make this environmentally unfriendly.

The proof of the pudding is that no one is putting serious money into this and if it really was the answer to our prayers, the hot rocks areas would be swarming like a gold rush.

So far, the hot rocks are a hole into which money is poured.

I would love to believe that a solution is in sight, but I am not yet ready to suspend reason like Kevin Cox.

In previous posts there do seem to be a considerable number of misconceptions. In particular on the danger of radon, thermal efficiency and even the effect of removing the heat.

Concerning the unjustified statements, one of great concern is the issue of radon from high heat production granites. It is not the abundance of heat producing elements that is the most critical, but the presence of an insulating layer of cover rocks so that the miniscule amount of heat generated is trapped and held for millions of years. There have been three hot rock projects that have measured radon emissions from granites during water and steam production Cornwall UK in the 1980's, Soultz France in the 1990's and the Cooper
Basin project in 2005. All three had relatively similar abundances of radiogenic elements in the granites and all three showed radon emission levels below background levels in many areas of the world where radon is not considered a problem.



Another concern is that of taking all that heat out of rocks 4-5 km underground. What will be the effect at the surface? The expectation is that there will be no effect. . In the granite the rock is 300ºC, but just 50km to the north, still beneath the Cooper Basin but in metamorphic basement rocks the rock is only 150ºC at the same depth.
It is true that the thermal efficiencies of power generation at 200ºC is relatively low, but it is incumbent on geothermal companies to prove that drilling, heat extraction and power conversion is an economically viable process. Now that some good results have been achieved it is looking less likely that the process is going to fail, particularly since the cost of other energy sources is now going through the roof, including coal without carbon capture and storage. With CO2 pollution taxes likely to be soon upon us and with the prospects of them increasing in time hot rock geothermal is looking more and more attractive.

For those interested in what the company has got to say, see http://www.geodynamics.com.au/IRM/content/home.html

Phil,

The suggestion that solar thermal power generation be used in conjunction with Hot Rocks was in the original article.

Effort is being made towards viable future energy sources, and huge amounts of money are being spent. Hydrogen fusion will probably work one day - it's just proved a lot more difficult than people originally thought. Work continues to be done on even safer designs for nuclear fission reactors, and on fission reactors that work on thorium instead of uranium.

But the need for future sources doesn't mean that every conceivable solution has to be worked on for ever and ever, despite evident problems with making them economic.

Democritus,

Development of hot rocks in Australia has not yet proceeded to the point where it generates power, but only because it takes time. So far there appear to be no show stoppers.

Rob pointed to the Geodynamics web site. Maybe the amount of money they've spent doesn't count as serious in your view, but in truth it's hard to see how they could have done things any faster by spending more

Sylvia,

Geothermal power is not old. Neither is it that difficult to do quickly if there was sufficient payback.

All that has been generated so far is Hype.

Democritus,

There's geothermal and there's geothermal. Hot rocks technology is not about plugging a pipe into a natural geyser.

They're drilling holes 4 to 5 kilometres deep into granite. That's not something you can do in a hurry.

Sylvia.

Thanks to everyone for the comments. Unfortunately the main message of the article was missed by many as they concentrate on the technology of hot rocks. The real message was that if we charge people more for energy but give the money back to them as Rewards for them to now invest in renewables we will reduce emissions. The difference in the market value of Rewards to their face value will tell us the opportunity cost of investing in renewables.

The other message is that there is an abundance of renewable energy available to be harvested. The energy is there - we just have to invest enough to develop it. We have no idea if hot rocks, or solar, or storing CO2, or nuclear, or windmills, or tidal or whatever is the answer but it doesn't matter. We know that the energy is there and we know that the marketplace in renewable infrastructure will provide the most cost effective way of achieving the result we want.

One way to get the market place in renewable infrastructure moving along is to make existing energy more expensive. We can increase the price with emissions permits or carbon trading. Another way is to tax emissions. Taxing energy but then giving the tax back to the people to now spend on renewable infrastructure is a socially acceptable and least cost approach to develop the market place in renewable energy infrastructure.

Taxing people be it through emissions permits or any other way and then relying on the government to distribute the money collected wisely is a very risky approach and no-one - including the government believes is wise. Relying on price signals to drive behavioural change and to encourage investors to put money into risky ventures is problematic.

Giving people money as Rewards to spend on renewable infrastructure will work. The tax burden is reduced because Rewards will have a value and this makes the tax more acceptable and stops the unedifying spectacle as everyone scrambles to get their piece of the tax pie for purposes other than reducing emissions.

Kevin Cox

To quote "The company successfully raised $11.5 million via an IPO in 2002, as well as further funds totalling $142 million for the 5 years to December 2007. Origin Energy Limited has also provided a significant financial boost to the company through its previously mentioned farm-in deal worth $105.6 million. Geodynamics currently has a market capitalisation of $306 m (191 m @ $1.60).

The company also plans to finalise its preferred design for a 50 MW power plant during 2008. Once operational (planned for 2012), the power plant, which will be for commercial operation and produce zero emissions with zero water requirements, will produce enough electricity to power approximately 50,000 households on a continuous basis."

This guys is small change in the power industry. 50MW by 2012, this is at best a pilot plant, and the money allocated and the time scales indicate that it is as yet not being taken seriously by industry.

Silvia, these holes are not drilled quickly, but can be done much faster with top notch equipment, and multiple drilling rigs.

If there was oil down there, there would be 50 holes already, and a $1bn worth of kit on the surface.

Democritus is right.

The capital cost and the immediate return on investment is the problem. Oil gives you a quick return on capital. Renewables take a lot longer and so if oil was down there investors know it will give them a guaranteed return very quickly. The way we calculate the "opportunity cost" or the time value of money is the reason investment in renewables is so hard to get. It is not that it won't work. There are 70 or more countries now getting energy from various geothermal opportunities (technically different from Innamincka but still geothermal)

If we have some money that MUST be spent on renewable infrastructure then the market place will ensure that it will be spent in the most efficient way. Trying to get investment in new technologies is difficult and just using the price approach of emissions permits will mean that the price of energy will increase to very high levels before people will take the risk. Artificial instruments like permits or carbon credits may (and have in the past) disappear with the stroke of a pen and that means it is going to take even higher prices to persuade people to invest because the risk is greater.

The simple Rewards solution of requiring the extra money collected from increasing the price of energy to be spent on infrastructure means the price of energy will not have to rise as high and so it MUST be less damaging to the economy to achieve the objective of reducing emissions.

Rewards fits into trading psychology that makes the deal fair - I pay more but in return get a Reward that I can now invest or sell. Emissions permits means that I pay more. Giving money to governments is seen as unfair by everyone who has to pay. Warm fuzzies and trust is not enough return and we want something tangible.

We can forget about the particular technology that will win out. The most cost effective will succeed and the country that gives the best deal to investors will be the one where the investment happens.

It's probably true if there were oil down there, there would already be multiple wells, because it is already *known* that oil reservoirs can be exploited.

At the moment, it's known that there is a body of hot rock down there, but it has not been demonstrated that it can be exploited. A large amount of money has already been spent, and more will be spent, in proving that it's physically and economically possible to extract the energy. The idea could yet prove unviable for some as yet to be discovered reason.

It isn't reasonable to compare oil investments with hot rock investments, because they're at completely different stages in the investment cycle.

Sylvia you are correct. The problem with investing in renewables is that the return on investment is unknown and risky. It is very risky if it depends on artificial products like carbon credits and emissions permits where the return depends on the whim of a government.

To take market share from an established technology a new technology has to be cheaper and better for it to be adopted. Renewable energy is no different.

Even in situations where there is an almost immediate return on investment companies are unwilling to invest because they have "better things" to do with their money. Our company would not spend money on insulation with a ROI of one year because we need all our money to increase sales.

To solve the emissions problem we need investment. The government could tax us and then distribute the money but that is an inefficient way to allocate resources. Fundamentaly emissions permits and carbon credits are mechanisms to encourage investment in renewables.

Giving the tax (surcharge) back to the purchaser and REQUIRING that the purchaser spend the money on emissions reduction infrastructure of their choice is a simpler and more direct way of solving the investment "inertia" problem. It uses the existing market place of renewable energy and emissions reduction infrastructure as the market place. It is simple and implementation is low cost and fast. The cost to the purchaser is the surcharge minus the return on the investment so the net cost is lower than a straight tax.

There are many innovative ways to distribute the tax to amplify the effect. For example we now tax the coal we sell overseas. Why not give some of the tax back to purchasers but REQUIRE them to spend the money IN Australia developing the renewable energy resource of their choice. The renewable energy would be in Australia and we can tax it in the future. There is an abundance of untapped renewable energy in the world and the countries with first mover advantage will get the biggest market share.