Google are taking an interest in this technology having produced a video discussing this technology.
Factors involved?
The main components making up this plant are water injection and steam extraction bores and a standard thermal power station. Water use is expected to be quite high initially and transmission costs will also be a considerable factor due to the acceptable areas for this technology being in central, uninhabited regions of Australia. Far from end users of the power. However and estimate has been made by Geodynamics that the energy stored in 1sq km is equivalent to 40 million barrels of oil. And with 50,000 km suitable area identified thus far, the resource could easily justify the capital outlay on supporting infrastructure.
What generation capacity is possible?
Current feasibility of a single plant with a generation capacity of 300MW.
Can this operate as a 24 hour base load power generator?
Yes.
Provided the water supply is continuous and recirculating/reusing of water is maximized, the main reliance of this technology is using the residual heat in the earths crust. This is essentially a non-depleting resource.
Has this technology been tested?
Yes in a similar fashion. Geothermal power plants are all over the world. Lihir Island near Papua New Guinea generates around 60MW from this resource and Iceland has very large amounts of geothermal steam available for power generation. Therefore the concept is sound and already in operation on an industrial scale. What is unknown is effectiveness of introducing water which will have to be high pressure pumped into the bore and the losses potentially incurred. If large amounts of electricity are needed (auxiliary load) and water are needed the running costs of this type of plant may prove to be uneconomic. However the energy costs associated with injection of water may be eliminated by the installation of solar operated pumps or wind generation facilities.
Multiple companies are investigating this technology. Geodynamics (GDY) listed on the Australian stock exchange is the most advanced developer in Australia of this technique. Altarock in the US has been established to Google have also taken a stake in this technology. The Carlyle group has also invested in Geothermal technology through Bottle Rock Power.
Estimated Financial capital cost?
Any size plant could potentially be built, however to remain economically feasible a proposed 300MW plant would be the minimum size. This is due to Auxiliary pump power requirements, water usage and transmission and distribution infrastructure which will need to be built. A 300MW plant at would cost in the area of $600M USD not including transmission infrastructure which will push the initial price up to around double that number. Installation of a water supply pipeline could add an additional $150MUSD to this figure. Total costs for a first single plant in the area of $1.85Billion USD. Additional plants around $400-$600M USD dependent on success utilizing this technology.
Estimated return?
Based on current retail rates generation of electricity over the 15 year life this technology is expected to return 5.03% p.a. for 15 years.
Power station operators, construction personnel, clean energy wilcatters, other drilling professionals, electricity transmission jobs, geologists, engineering personnel. The skills required for this type of installation are all of those associated with drilling and exploration and building and operating a significant sized steam operated power station.
As these resources are local, including throughout the United States, not overseas, the potential for jobs in local areas is immense. There is also potential for manufacturing facilities to be built or need to ramp up production to meet the needs of these new plants. Both in exploration equipment and generation equipment. The potential for creating local jobs is significant.
Where is this suitable?
Central desert areas with semi-stable geological formations.
Google have produced an excellent resource map for the United states where this technology could potentially be installed.
As discussed, water reuse, water infrastructure, high pressure pumping power use versus end output, power distribution infrastructure all need to be addressed before this could be deemed an economic solution. A major investment in this infrastructure and proof of concept could see enough suitable areas which this company currently has access to, able to provide all of Australia’s electricity needs for 250 years. As it not based on accessing current areas with the potential for aquifier contamination is limited. This process utilizes a close loop system so water losses are anticipated to be minimal. Life cycle degradation of the heat source needs to be considered, potential mineral contaminants in the steam prior to use in the turbine cycle also will need to be dealt with.
C02 emissions?
The net advantage of the plant will be equivalent to reducing green house emissions by 2,628,000 tonnes of carbon dioxide per year if a 300MW plant is built. This is not the end power available however, so this figure will reduce dependent on transmission losses and auxiliary load (pumping).
News
GDY are highly advanced with the development of the first plant having completed the terms of agreement with Origin energy, a major international electric company, to build the first plant in Australia.
