Hi Raysea - I guess "technical risk" is a relative term. The...

Hi Raysea - I guess "technical risk" is a relative term. The document you refer to makes it clear that the biggest power generation developments in SA have been wind farms and domestic rooftop solar PV. The latter, combined with energy efficiencies (ie use less power due to high cost), is leading to significant reductions in consumption. Wind is the only new capacity to the grid.

This general pattern is the same all over the developed world, in some places there are also large solar farms making significant contributions.

The point is that both wind and solar are easier to build than EGS geothermal because any decent engineer can easily and cheaply measure the resource and build the structures. Financiers and regulators can more easily visualise the projects, because they can see them, and appreciate the relatively short time-frames. For geothermal you need to have at least a basic understanding of geology to understand what is happening, and highly specialised knowledge and confidence to build things which you can't see and which lie at the end of a 4 km long pipe.

I agree GDY achieved the operation of a 1 MW pilot plant, but it took a very long time and a huge amount of money to achieve it. How many solar, wind or conventional power plants with much greater capacity could have been built with those resources? Unfortunately geological conditions are also highly site-specific so, for example, any lessons learned by GDY may not necessarily be useful to PTR. Wind and solar plants can be replicated almost anywhere.

Personally, as a geologist, I love geothermal and believe it is the best long-term technology to replace coal and gas-fired base-load power plants. However, wind is becoming its biggest competitor. It provided 27 % of SA's power in 2012-13, compared to 4 % from rooftop PV, 52 % from gas and 17 % from coal.

Of course wind is intermittent and geothermal is not - so what is the extra cost to the grid for handling that intermittency? This will be where geothermal's advantage will lie.

In some places around the world geothermal will have a natural advantage because it occurs at shallow levels because of an association with volcanoes. These should be exploitable relatively easily and cheaply. GDY's Pacific projects fall into this category and so should PTR's Tenerife project.

Unfortunately, I think the non-volcanic Australian geothermal industry largely wasted its opportunity to use taxpayer funds to develop its deep technology, and I can't see when or how it will get another opportunity in the short-term. It would help if GDY gets a customer for its pilot plant output, otherwise we may have to wait for proof-of-concept developments overseas, particularly from the US and to a lesser extent Europe and China.

As for the major gas and coal generators, I think they should be interested in geothermal for their long term development but I suspect they are just waiting for someone else to do the heavy lifting. They can afford to move in later when the hard work has been done.

Elsewhere in Australia I think there small-scale opportunities to replicate the Birdsville geothermal plant throughout most of the Great Artesian Basin, using new micro ORC plants which can produce power from 80-115 C water. Beneficiaries would be off-grid farms and small towns, but the market would not be large. However, this might be an intermediate step to re-building the larger-scale, deep EGS industry over the longer term.. Perhaps PTR could take this up.

Well, that was a long rant off my chest. Better get some more coffee..