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.