Thursday, April 12, 2007

Hot rocks: a cheap and clean energy solution?

There’s been a flurry of media reports in recent weeks about the promise of geothermal energy in Australia:

PEOPLE could be using "green nuclear" energy in their homes within three years as entrepreneurs rush to produce zero-emissions electricity. Geodynamics Ltd told the Australian Stock Exchange yesterday it had sped up plans to harness the heat generated by natural nuclear activity deep beneath the central Australian desert. The company plans to pipe high-pressure hot water from the granite bedrock four kilometres beneath the Queensland-South Australia border, where the slow decay of potassium, thorium and uranium generates temperatures as high as 300 degrees...

Dr Williams expects the company to send electricity to the national power grid by 2010 and later directly to western Sydney. By 2015, it could produce as much electricity as the Snowy Mountains hydro scheme. Some scientists say hot-rocks technology could soon deliver huge volumes of economically viable power, thanks to the continent having the hottest and most geologically favourable granite deposits on earth.
The extent to which this technology is exploited comes down to its economics, relative to other energy sources:

The greatest impediment to the renewable energy industry is that the nation's electricity is among the cheapest in the world, thanks to huge deposits of high-grade coal. But geothermal energy is expected to be economically viable after a moderate cost is imposed on greenhouse gas emissions.

Geodynamic, assisted by $11.8 million in federal grants, said it would produce one megawatt of electricity for about $45 an hour - compared with coal power of about $35. The Prime Minister's taskforce on nuclear energy estimated the cost of nuclear energy at $40-$65, "clean coal" at $50-$100 and photovoltaic solar energy as high as $120.
So what should we do about geothermal power? Should we be investing in it? Or in solar and wind? Or in clean coal?

A low risk strategy would seem to be to start putting a price on greenhouse emissions, through some kind of carbon tax or emissions trading scheme, and letting investors put their money into what they assess to be the technologies that offer the best opportunities for power that’s relatively cheap and low-emission. These could be kick-started, where appropriate, by modest grants.

Of course, you don’t actually need to put a price on emissions to encourage investors to put money into researching and commercialising these technologies. There’s no price on emissions at the moment – coal power stations can emit all the carbon dioxide they like and they don’t have to pay a cent – but investment is occurring. The reason is that everyone realises there will be a price on emissions in the future and it’s time to start investing accordingly.

I suspect this is one of the reasons we’ve seen the apparent paradox of industries that stand to lose from carbon taxes and the like actually advocating that governments introduce a clear carbon price. If they have a good idea what the price on emissions will be over the coming decades, they can plan how much to stick with coal or oil and how much to invest in alternatives. At the moment, all they can do is speculate.


justakim said...

I remember from my first environmental science class years ago, that 'the problem with geothermal' was the impurities that is mixed in with the steam. I don't remember exactly, but I would imagine it's minerals that make it corrosive. Has anything in technology changed that has made it more viable, or is it the growing cost of other options?

Paul said...

Hi Justakim,

As a long-term shareholder of Geodynamics (with a vested interest) I've examined the science and practical considerations rather carefully and 'corrosion' would not appear to be an issue and has never been mentioned. Your science lecturer was likely discussing more traditional geothermal technologies with the HFR (Hot Fractured Rocks) technique being employed by Geodynamics. The beauty of HFR is that it takes place in geologically stable areas (i.e. no earthquakes or volcanic eruptions) and in areas which, based on the general geology of Australia, would be inherently low in corrosive minerals. Furthermore, if these minerals were present the recirculating system could easily be flushed with additional clean water and inhibitors if required. As I said, it has never been stated as an issue.

This technology is, in my humble opinion, the best single option that we have for producing zero-emission base-load power. I should also add that the known resource of hot rocks is probably only the tip of the iceberg and current estimates are very conservative. The amount of heat energy within the earth's crust is virtually infinite and in a process of constant renewal through natural radioactive decay. What's more, the technology to extract this heat already exists. It is about time that this technology is finally getting some of the attention it clearly deserves. Australia is in an extraordinary position to make good use of this outstanding renewable resource.

laura said...

I'm not sure how the geothermal guys plan to get over the significant economic hurdle of the distance from their plants to the grid. very pricey.
a carbon price, if it was high enough (the current models would really only lead to more gas being used), would naturally favour the cheapest alternative, which in the renewable sector is wind.
we need a price on carbon and a renewable energy scheme (ie. VRET, NRET, an increased MRET)

Anonymous said...

thnx for your post. i had heard of geothermal, but i was not aware of any large-scale projects being planned.

Anonymous said...

Thanks a lot it helped me in my science fair project

Anonymous said...

thanks a lot it helped me with my project

dan said...

thanks a lot it helped me with my project

Anonymous said...

thanks a lot it helped me with my project

Anonymous said...

Has anyone asked why the radioactive decay occurs so deep underground? Would there be a natural purpose for the decay to occur well away from where we dwell? How would we feel if someone came to drill a well into our hearts to extract our endless supply of Love?
Seems to me like we can remember "what we do to our home, we do to each other" Baseload or none, what is our baseload and what is our respect for the natural purpose of decay occuring so deep beneath us? I'm deeply grateful that the decay occurs so deep undergraound to make this planet habitable. Let's explore some simple options before we make complicated and flimsy exploration.

mariana said...

well i dont get how much it costs and why?

mariana again! said...

i have a question- im doing geothermal hot rocks for a science project and my question is "does the cost of this energy make it prohibitive for common use...why or why not?" well i know geothermal hot rocks cost 6 cents per kilowatt-hour and $1700 per kilowatt installed. why does it cost this little? i know it runs on a constant source of free fuel, but are there any other reasons? please comment back i need some help by today.

tom costello said...

omfg do u know wat hot rocks are or is this even just a site for watever?

calvin said...

Geothermal energy is the cheapest form of clean energy out there, with wind energy a close second – and both could become cheaper than fossil fuel-fired energy if governments will direct more research funding to them.

That's according to a new report from New York University Stern, which calls for governments to start putting more money into geothermal and wind power research to yield faster and more dramatic improvements than money put into solar research.

Geothermal energy was singled out as the cheapest renewable energy source out there, and could become competitive with coal and gas-fired power with about $3.3 billion in research and development spending, the report said.
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The United States got about 2800 megawatts of geothermal energy in 2006, or 0.3 percent of the total. But it only costs 4 to 6 cents per kilowatt hour to make on average, according to DOE's Energy Efficiency and Renewable Energy division – close to the ultra-cheap price of energy made from coal, but without coal power's massive carbon emissions.