Enhanced geothermal systems is a term that tends to make people thoughts wander off and think about other things – like a cold beer.
However, it's a really important concept that opens up the full potential for the future use of geothermal energy. So pay attention and have the cold beer when you finish reading this article.
The article also contains a couple of really informative videos, so make sure you watch those too!
Traditional geothermal power plants
The prevalent geothermal energy plants tap into underground steam or water reservoirs, using binary cycle systems where the steam that drives the turbines is condensed and fed back into the underground reservoir.
These plants aim to replenish the reservoir so that it is not exhausted over time.
However, such reservoirs do not occur everywhere and if geothermal energy was to realize its full potential a breakthrough was needed.
Enhanced geothermal systems
The system involves tackling areas where there is no existing reservoir of steam or water but where there is rock with sufficient heat, say150°C (300°F), and then breaking up or fracturing the rock formations and then pumping in water so that it can be heated and brought back to the surface as steam to drive turbines and produce electricity.
The following video illustrates the process:
Google, everyone's favorite search engine company, has invested heavily in the development of this technology. At the moment, in the USA, there is about 3,000 MW capacity in geothermal plants and it is estimated that if EGS technology is used then the potential is there to increase that capacity by a factor of 1000. When you look at the potential worldwide then it is absolutely mind-blowing.
Remember, geothermal energy provides base-load power, 24 hours a day, every day.
Team up the enhanced geothermal systems with wind and solar and the world has the potential to shut down the fossil fuel plants that not only wreck our environment but also our health.
Enhanced geothermal systems – the risks and drawbacks
With any new technology development there are always possible drawbacks and associated risks.
In the case of enhanced geothermal systems when you use water, under pressure, to widen the fissures in existing rock formations there is a risk of seismic activity which might result in an earthquake.
This requires careful research in the exploratory phase and also careful monitoring in the production phases.
Obviously, one avoids putting such a plant on an existing fault line or close to a major population center. However, even so, the risks remain. It then becomes a question of careful monitoring and adjustment so as to control the extent of seismic disturbance. Scientists and engineers working in this area are confident this can be managed.
Fortunately there are working projects in Australia, Germany and the USA. What is needed is more successful projects so that public acceptance is obtained.
At this stage it is important for governments to fund research and development of demonstration projects so as encourage the private sector funding that will be vital to future expansion.
The following video explains the situation on balancing risks very well.