The Beware of Movies! series is meant to point out some of the scientific inaccuracies of popular movies, specifically in points related to the geological sciences.
This post will point out the major inaccuracies portrayed in movies about the Earth’s resources, especially for energy. Unfortunately, there aren’t too many movies that really touch on this topic, so this will mostly be a short essay about energy resources. How do we get oil and coal?
Please make note of appropriate movies related to these topics in the comments if you know of them.
What are Natural Resources?
By natural resources, I’m referring to those things that we pull out of the ground to satisfy our own needs. Most of us think of water or oil as resources, but there are others. Many resources are also energy resources, like oil, gas, and coal. Water isn’t necessarily an energy resource, unless you’re thinking about geothermal energy.
Some resources are limited, and others are renewable. We think of energy from the wind or the sun as renewable resources, since neither is going to go away any time soon. Coal and oil, as well as many of the mineral resources are non-renewable, meaning that once we’ve dug them all up, that’s it. There’s no more.
What is meant by ‘reserves’?
We talk about the amount of materials we are able to extract from the Earth, and use this term ‘reserve’ to describe it. Reserves are the part of the natural resources that we are either actively extracting, or know we will be able to actively extract later.
The definition gets a little fuzzy when considering economics. In most cases, deposits of the materials we’re interested in extracting aren’t considered resources if it’s too costly or difficult to mine them. Once the technology is developed, deposits not formerly considered reserves, suddenly are.
Consider natural gas, for example. The best case scenario is when there are pockets of gas in convenient places where we can simply stick a hose in and suck it out. Such deposits are getting rarer, so now we’ve begun to try hydraulic fracturing, or just ‘fracking,’ to get the gas out of rock.
Fracking is the Devil, right?
Hydraulic fracturing (fracking) has become a politically charged issue. The principle is sound. Natural gas is found in deep rocks (shale), but can’t be pumped out because the rock is not sufficiently permeable to allow the gas to flow. We pump water in at high pressure, which causes the rocks to break, then when we pump the water out again, the gas comes out, too.
Problems arise from two fronts. 1) The water we use to do the fracking usually has a number of chemicals added to it to facilitate the fracturing process. Some are surfactants (soap), others are chemicals to help break down the rock. Something has to be done with this water once it’s been used. Some of it is re-used, which is good, but in the end, you still are left with a lot of contaminated water. 2) If the wells we use to pump the water in and out are not properly constructed, the water or the gas can escape the wells and contaminate drinking water supplies. This is where we see people able to light their tap water on fire because of natural gas contamination.
These are real problems, but with proper management and well construction shouldn’t ever happen. There is a fair amount of confusion about fracking. Most people don’t realize that the shale layers to be fracked are generally thousands of feet deeper in the Earth than are the deepest wells that provide drinking water. There really is no way for the fracking fluids to directly contaminate drinking water supplies. If wells are properly cased, then the only real environmental hazard is with the waste water itself.
Whether fracking is the devil or not, well…
Dinosaurs decayed to make oil, so why do we always look in the oceans or Saudi Arabia to find more?
One of my favorite misconceptions is that somehow the oil we burn was once dinosaurs. I think subconsciously, most people realize that this can’t possibly be the case, but if it’s not dinosaurs, what is it? Most oil is derived from the decay of ancient plants, just like coal. Where there were once plants, we might find oil.
The thing about oil (and gas) that is different from coal is that it tends to move. Oil will flow through the rock and get trapped into little pockets of rock. These pockets are usually formed by impermeable barriers like shale or other structures (faults) that the oil can’t flow past.
The challenge for us, then, is the find these little oil trap and drill into them. So how do we do that? Geologists discover these traps first by surface mapping and studying the orientation of geologic structures (like faults or tilted beds) and predicting what the geology is like under the surface.
When the surface is inaccessible, or we want to get a better image of the subsurface, we can use seismic studies to see what lies below. Seismic surveys utilize the fact that vibrations pass through rock and bounce off of any discontinuities that might be down there (like faults or changes in rock type). For shallow seismic surveys to look for oil, geophones are set up to ‘listen’ for the vibrations when a charge is detonated or a ‘shaker truck’ sets up a series of vibrations.
On land, geophones are stuck into the ground some distance from the vibration source (whether it be a shaker truck or an explosion).
In water (such as in ocean surveys), hydrophones are towed behind a boat. Air blasts into the water are used to set up the vibrations.
The vibrations recovered by the geo- and hydrophones are reduced with computer technology to make an image that can be interpreted to see the structures under the surface.
Once the seismic has been interpreted, geologists look for the structural traps that could hold oil or gas and then discuss the feasibility of drilling to extract those materials.
Beware of Movies: In the movie Jurassic Park, there is a small-scale version of seismic used to find dinosaur skeletons in the opening sequence. A shotgun blast is used to create the vibrations that are read by the geophones. The problem is with the type of image that results. Sorry folks. There’s no way that you’ll see a perfect image of a Velociraptor skeleton from a single shotgun blast.
Oil and Gas are important resources, because I like my car and the lights in my house. What is all this hype about Peak Oil?
Peak Oil is an interesting and mis-understood problem. We do know that there are limited oil reserves on the Earth, but we’re still exploring and finding more oil. Recall that reserves are the sources that are already being drilled or will be eventually. So the reserves basically are all the oil we have.
Right now, we are able to produce enough oil to meet demands, but at some point oil production (getting it out of the ground and processed for its final use) will no longer be able to keep up with demands. This will be due to the combination of diminished resources and increasing demands. This point is called “Peak Oil.”
So, where are we on the curve?
Depending on whether you consider the entire world, or just one continent at a time, we are just at or just beyond peak oil. Our reserves will increase slightly with new discoveries and methods, but they will not keep up with demands. While production is still increasing, soon, production will decrease. This will undoubtedly cause increasing costs and shortages.
Well, we’ll always have coal.
Coal is commonly used to run the power plants upon which we rely for our electricity. But it is also a limited resource. We can look at coal production just as we look at oil production and think about ‘Peak Coal.’
Even though there is still a lot of coal left, the world is past its peak for coal production. We had best not plan on coal as an infinite energy source.
What else is there?
There are a few other options for natural energy resources, many of which are renewable, but all are not economical at this point. For example, enhanced geothermal systems have great potential, but are extremely expensive to implement.
Alternative energies like wind and solar also have great potential, but the equipment required is costly, and in the case of solar energy, requires the utilization of other difficult to produce natural resources, like silicon for the solar collectors, or lithium for the required batteries.
For this, I don’t have any good solutions. I only present this information here for you to consider. If you don’t like the potential outcomes implied by this, I encourage you to do some more research, or contact your local legislator and tell him or her that you’re concerned.
Water is too an energy resource! Hydroelectric generators have been around for a long, long time. Like wind and solar it’s very cheap to produce, but expensive to build a plant to produce it. Unlike wind and solar, economy of scale makes it cheaper to build a big hydro plant than a wind or solar plant with the same capacity. So you get big plants like the ones along the Niagara River, which supply a big chunk of the Northeast’s power demands.
The reason hydro isn’t more common is that it requires a very specific geologic structure: lots of water on top of a hill that can be convinced to run down quickly, and a way to replenish the water at the top of the hill. There are a limited number of sites with those characteristics, and they’re not making any more.
I think some of the resistance we’re seeing to fracking is people remember how groundwater was ruined by unscrupulous oil drilling in the last century. I grew up in Southeastern Ohio where there was a small oil industry. There were areas there where wells had not been properly cased, allowing crude oil into the fresh water aquifers that fed most wells in the area. When you know somebody who had to abandon their home because their well was contaminated, you tend to be a little skeptical the next time someone suggests drilling for oil in your back yard. (Not that I oppose fracking. I think it’s a good idea, but I think the people doing it need to be watched carefully.)
I did rather leave out hydroelectric, didn’t I? Just like hydrothermal, you have to have a lot of pieces already in place before it’s economical or even possible.