Geothermal energy has some serious implications for the future of power generation. As a long-term solution to our world’s energy problems it promises a great solution: clean energy in a renewable fashion, using only the heat of our planet.
Of course, whether or not it’s truly a viable long term solution is up in the air however, and there are some definite pros and cons to the whole thing.
Before we dive into all of that, let’s take a look at just what qualifies as geothermal energy for those who aren’t studied up on the matter.
Harnessing geothermal energy
There are three main types of geothermal energy plants currently in production, each of which has their own advantages and disadvantages.
Dry plants utilize steam from geothermal activity. Rather than having to go through a series of different actions, these plants utilize the steam which is released through vents directly in order to spin a turbine and power up a generator.
Flash steam power plants use high-pressure water from underground, pumped upwards. As the pressure lessens, a good portion of the water is converted into steam, which then powers a turbine and loses its heat
The now-cooled water is returned underground after passing through a condenser, and injected back underground in order to continue the power cycle. The vast majority of geothermal plants use this technology.
The third type of plant is a binary plant. These plants aren’t all that common since they’re much more complex but the basic principle is pretty easy to understand: they use the heat from underground water in order to heat another liquid through heat exchange.
The secondary liquid then boils and the vapor is used to power turbines, while the condensed liquid returns to the cycle in order to ensure that it continues for some time to come. The liquid used is generally a condensed hydrocarbon with a low boiling point, such as butane, so that the heat exchange can be made efficiently.
All three types of plant are currently in operation in different parts of the world, with each being favored for utilizing the geothermal properties in different areas.
The pros of geothermal energy
There are a lot of advantages to the utilization of this form of energy, and it’s easy to see why it’s use is starting to take over a larger section of the energy economy:
- Environmentally friendly-Geothermal plants don’t produce a substantial amount of pollution. This makes them extremely green, and in the case of flash steam power plants there’s virtually no exhaust except for water vapor.
- Sustainable-Unless you’re talking a galactic time scale, geothermal energy is extremely sustainable. The reserves naturally replenish over time and are virtually inexhaustible, even considering the growing need for energy.
- Extremely high potential-Current estimates for the maximum production of geothermal power run around 2 terrawatts. While it’s unlikely to reach that far anytime soon, that’s about a ninth of the power used in the world on an annual basis.
- Small footprint-Large portions of geothermal plants can be built underground, limiting their effect on the environment above ground.
- Readily accessible-While not able to be exploited profitably in all areas, geothermal energy is theoretically exploitable pretty much anywhere on the surface of the planet.
- Advancing technology-One of the most exciting things about geothermal technology is that the only thing holding it back from being pretty much everywhere is the technology. If costs come down enough we could have an absolutely golden opportunity at our fingertips.
Sounds good, doesn’t it?
Geothermal energy actually has a longer history than many people give it credit for. The oldest geothermal application was actually a large heating system in Chaudes-Aigues, France which has been operating since the mid-14th century.
Indeed, geothermal heating applications are still used quite often. By pumping fluids underground and allowing them to heat, they can produce some pretty impressive effects when it comes to water heating for instance.
As a possible future application this can actually save quite a bit of energy in many areas, since a lot of energy goes into heating water for both residential and commercial applications.
Let’s explore the downsides to this valuable resource before we come to any solid conclusions.
The cons of geothermal energy
There are some definite downsides to geothermal plants as well.
- Pollution issues-While nowhere near the emissions of coal plants, depending on the area that can be some nasty stuff emitted from geothermal plants. Sulfur dioxide and silica are two of the main culprits, but heavy metals are sometimes contained in the steam released due to their presence in underground reservoirs.
- High upfront costs-Geothermal power plants cost a lot to put in. Apart from the plant itself and the machinery contained therein, there’s also the need to drill down in most areas in order to get proper access to the thermal energy below.
- Surface instability-Probably the worst issue with the construction of geothermal plants is that their construction can create earthquakes. There have been documented cases where this wasn’t just a possibility but actually happened.
- Location specific-While it’s certainly possible to harness geothermal energy in almost every area on the face of the planet, the ability to pull serious amounts of energy is limited to just a few areas on the surface of the planet.
Except for the possible generation of seismic activity most of the disadvantages inherent to geothermal energy generation are quite minimal.
While it’s not quite as clean as, say, solar energy it’s still quite a bit cleaner than fossil fuels and there are sufficient locations to generate a considerable amount of the world’s energy requirements even with the current levels of the technology.
The seismic activity definitely isn’t a joke, however, a recent geothermal drilling attempt caused hundreds of earthquakes in Switzerland centered on the drilling site.
It’s important to keep in mind, however, that most of the plants which have been installed so far have been completed with minimal changes in the seismic activity in the surrounding areas.
A place for geothermal energy
Geothermal potential simply isn’t at the point where it’s going to be the be-all, end-all of future technology but as things improve it has the potential to be able to reliably take up a large chunk of the burden from other renewable energy sources.
The biggest thing which needs to be done is to make sure that geothermal plants are as sustainable as possible, since mismanagement of the water reservoirs used can lead to them diminishing over time. Fortunately, current techniques have a strong focus on making sure that the majority of the water is returned, to make the plants as sustainable for a long time.
Currently geothermal power suffers from some underfunding which may prevent it from reaching the targeted goals of the industry in the coming decades.
The development of geothermal energy is a serious boon in many places around the world. While the US, for instance, has a large amount of plants installed there are many places around the world where it’s quite promising.
In areas which are somewhat short on fuel but have active volcanoes, for instance the Eastern Caribbean, it’s one of the most viable sources of energy available.
There’s a lot to look forward to, provided that the funding does come forth.
The hottest part of the energy revolution
Geothermal doesn’t receive quite as much attention as wind and solar power in the sustainable energy discussion. This is primarily due to the fact that it seems to be quite location-dependent at first glance.
The reliability of geothermal energy can’t be underestimated, which means it’s one of the best possible adjuncts to the less reliable solar and wind powered options which have taken center stage in the world’s attention.
This unfortunate discrepancy has a two-fold cause: geothermal is less talked about simply because it’s less well known, and at this point in time the proposed scaling of even the best technology isn’t going to make it a universal solution to the world’s growing energy needs.
Currently it makes up a rather small part of the energy being supplied to the world, especially in developed nations.
What many people fail to realize, however, is that even if geothermal can only supply 10% of the world’s energy at its peak, then it opens a lot of doors. Since it’s sustainable for extremely long periods when the water utilized is re-injected into the ground, it is a long term solution.
The world is advancing towards the usage of more and more renewable energies, that much is certain and can be widely seen in broad trends across the globe. Geothermal may not have quite the same flash and allure as wind and solar energy, but it might be a great capstone on top of other renewable efforts as we move into the future.
The pros and cons of geothermal energy are pretty clearly laid out. Reliable sources of energy with lasting power, and the technological development to back it, are pretty rare but in this instance it turns out it can be found just under the Earth’s crust.