Energy Sources: Our Options


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So, here’s the new post! In my last lesson I told you something about energy security and why it is important for us on a national as well as on a global level. Today, we will learn about the different energy sources that are used right now, and which ones could be used in the future. By the end of this unit, you will also see why people have to deal with the question how to provide energy in the future.

Our energy sources and their impact on the environment

The variety of different energy sources on Earth can be divided into three groups:

Energy classification

Classification of energy sources

Non-renewable energy sources, like crude oil and coal (fossil fuels), are finite. Humans exploit them, and as a result they will run out sooner or later. Renewable energy sources are continuous flows of nature. An example is wind. These resources can be constantly reused. Some energy sources are recyclable, e.g. uranium, which is used in nuclear power plants. It can be reprocessed and used again. Above you can see an overview of the most common resources, and which type of energy each one belongs to.

Our energy sources have varying environmental costs, depending on their production and use. In general, non-renewable sources are a major reason for global warming, and using renewable sources often means less harm to our environment. However, as the pie chart on the left indicates, only about 8% of the global energy that is consumed comes from renewable energy sources. (The statistic is from 2006, but the latest versions look pretty much the same.) In the following, I briefly want to present you each of the energy sources I’ve listed in my overview above:

Crude oil, or petroleum, and natural gas are fossil fuels found deep under the Earth’s surface. They are produced in terminals and refineries that take up large areas in often environmentally sensitive regions, e.g. the Arctic. There is a risk of oil spills and gas leaks. Such accidents have happened before and caused terrible damages to wildlife and vegetation. An example is the huge oil spill near Australia’s coast in 2009. It killed thousands of marine animals and threatened the Great Barrier Reef, which is the natural habitat of innumerable endemic species. What is more, burning oil and gas to produce energy releases greenhouse gases, and thus increases global warming.

Wagons loaded with coal

Another fossil fuel is coal. It developed from plants that died millions of years ago. The dead plant matter was buried beneath the surface by different layers, like sand and mud, and gradually turned into coal by biological and geological processes. Coal is produced by mining, which damages the environment, and burned too, so that this source of energy releases greenhouse gases as well. Besides, it is heavy to transport. This creates further greenhouse gas emissions. Like oil and natural gas, coal will run out one day, but while experts say that oil and gas will run out in 50 or 60 years, coal reserves are expected to last a few decades longer.

Uranium is another non-renewable energy source. It is used in nuclear power stations and can be reprocessed, which is why it is also a recyclable energy source. Uranium can be found underground. It is a finite energy source, but it will most likely not run out as quickly as for example coal, because we need much smaller amounts of it to produce energy than we need of coal. Uranium is a very dangerous energy source because it’s radioactive. Accidents like the one in the nuclear power plant in Chernobyl, Ukraine, in 1986 have proved what dramatic effects radioactive material can have. The vegetation around the power plant immediately died, rivers carried the deadly, radioactive water to other European countries, and local residents had to abandon their homes. Many animals and people who were contaminated with radiation died, became terminally ill or gave birth to seriously disabled children.

This solar plant in Spain features 15 hours of storage and can supply power 24 hours a day.

You have certainly noticed that there is a variety of renewable energy sources, and those I have listed above are only the ones that are currently used the most.

Solar power is an unlimited resource, just like the other renewable energy sources. Producing it does not release greenhouse gases. However, to get enough energy, large areas of land must be covered with photovoltaic cells or solar panels.

A wind farm in Texas, USA

Wind power can be used by installing wind turbines. Some people argue that they disturb their view of the landscape, and they can cause an annoying noise for people who live near them. Besides, they can have negative impacts on birds because they cause movements of the air. But the advantage of wind energy is that it can be used almost everywhere in the world because all you need is wind.  It is a good resource for countries like Great Britain, where it is quite windy due to its location on an island.

Wave power is not yet developed very far, but the basic principle is using the energy that’s transported by ocean waves by installing so-called wave energy converters. Wave power can be combined with wind power by combining the required machinery and installing it offshore.

Tidal power means using the power of tides and converting it into useful energy forms, e.g. electricity. Actually, in most cases renewable energy sources are used to turn any form of natural energy into electricity. The problem with tidal power is that barrages are built to harness the energy. These barrages disrupt natural processes, like animal migrations, and damage marine wildlife habitats.

Biomass usually means plant matter that is burned to produce electricity or heat. The burning can release greenhouse gases, but it can also be used as a methane gas fuel. In this case there is very little greenhouse gas emission.

Another renewable energy source is geothermal energy, which means using the heat that is stored in the earth. Its disadvantage is that you can only produce a significant amount of energy with it in volcanic areas, e.g. Iceland. In these regions there is a constant risk of volcanic eruptions, earthquakes, and emissions of toxic gases.

The Gordon Dam in Tasmania, Australia

And finally, the most widely used renewable energy source is hydropower. The gravitational force of falling or flowing water is used to generate electricity, hence the term “hydroelectricity”. If less energy is needed that produced, a popular way to store the energy is to use it to pump water back up into a lake that lies behind a dam. Now it can be used again by conducting it down and turning its energy into electricity. However, hydro-electric power has some significant negative impacts on the environment. To create the large lakes behind the dams of hydro-electric plants, huge areas of land are being flooded. The drowned vegetation decays and releases greenhouse gases. Besides, silt settles in the artificial lakes instead of flowing downstream where it is usually used by farmers to fertilize the land. That’s why they often have to use chemical fertilizers which are environmentally unfriendly. What is more, sometimes dams collapse due to earthquakes or other causes and destroy huge areas of useful land.

The issue of using fossil fuels

Some of you may have read my post about energy security. I that lesson I’ve already explained that fossil fuels will most likely run out in a few decades because we are exploiting their sources. Nonetheless, we rely on them and get most of the energy that is consumed worldwide from those reserves. The fact that we are running out of our non-renewable energy sources has caused constant price rises over the past decades, like for example at petrol stations, and I believe at least everyone who owns a car can relate to that.

Besides, coal, oil, natural gas, and uranium reserves are distributed unevenly. For example, the map below indicates that the greatest part of the world’s oil reserves can be found in the Middle East:source:,r:0,s:0,i:82&biw=1280&bih=642As those who have read my last post already know, the uneven distribution of energy sources in the world can be used by countries who have many resources to put those that have to import energy from them under pressure. This dependence on each other for one’s energy supply affects the global energy security. It’s a major concern of the USA to be dependent on oil from the Middle East, and other countries are worried about their energy supply as well. What if someone started a war and disrupted the flow of energy? What if terrorists managed to destroy the infrastructure that is necessary for the transport of energy from exporting countries to those that consume the energy? Another problem is that while our global reserves are diminishing, the worldwide demand for energy is increasing fast. Rapid technological advance has made us get used to a 24-hour-access to energy, especially in the western world. Can you imagine life without electricity? Without being able to get to work by bus or by car every day? Without a TV you can relax in front of in the evening, or a computer that means the door to your friends who live on the opposite side of the Earth? I guess you can’t.

In fact, most of us can’t. This is the reason why scientists are trying to find more efficient ways to use renewable energy sources. We are beginning to understand that our oil and coal reserves won’t last forever. It won’t take very long until we’ll find ourselves in a future without fossil fuels. We can either prepare for this future, promote renewable energy sources, and create a smooth transition, or we can try not to think about it and just enjoy our present lives, exploiting our finite resources until nothing is left of them. Whichever way we decide for, that future is coming nearer, and we’ll have to accept it sooner or later. The following video summarizes our recent history with fossil fuels, and it also clarifies what our future could look like:

Human independence from fossil fuels – is that realistic?

As the video shows, our economy is dependent on fossil fuels. Especially more economically developed countries (MEDCs) base their economy on their non-renewable energy sources. The narrator in the video referred to our future without fossil fuels as the “post-carbon future”. We know that this post-carbon future is not too far away anymore, but still our demand for fossil fuels is actually increasing. The world population has reached 7 billion people (if you write down the whole number, that’s 7 000 000 000 – with nine zeros!), and everyone wants to keep their lifestyle, having access to energy all day and in every situation. Modern societies are organized in a way that forces people to consume more and more, and to base their lives on the supply of fossil fuels.

To end our dependence on fossil fuels, we must begin by understanding the full extent of our reliance on them. If we want to prepare for our post-carbon future, it’s not enough to promote renewable energy sources and install photovoltaic cells on the roofs of our houses. No, we must rethink our entire lifestyle. We must be aware of the fact that our transport systems, as well as the production of innumerable goods we are used to pick up at the shopping centre at any time we want, are dependent on fossil fuels. At this point, I want to quote one of the experts who speak in the video clip below: “The solution cannot be to do less of the same thing. More or less tightening our belts will not solve the problem. We need to invent lifestyles and ways of consuming and producing that are radically different.” This means that it isn’t enough to reduce our energy consumption and try to maintain our current lifestyle as long as possible. We have to reorientate ourselves and find a way of life that harmonizes with the new conditions. I’m saying that we must redesign cities and invent sufficient vehicles that are powered with renewable energy. We must invent new ways of production and transport. Clear and brief, the disappearance of fossil fuels will affect almost every part of our lives.

But if we realize and accept that there is this huge transformation ahead of us, I believe that we can create a world that is independent from fossil fuels. Well, of course the world has never been dependent on them, it’s only us humans who are. If you imagine that the Earth would have been existing for one hour, then human life would have been there for less than a second. I like this comparison, because it shows so clearly how short the time we have spent on Earth so far has been. Just like the dinosaurs, we’re only one small chapter in this planet’s history. The difference between us and the dinosaurs is that they haven’t destroyed so much of their habitat in such a short time. We haven’t stopped polluting our environment, destroying habitats and ecosystems, and causing species to become extinct, since we first started to use fossil fuels to produce energy.

However, I am convinced that there is no point in continuing like that. If we want to enjoy life on Earth for longer than a few more centuries, we have to find a way of life that protects our environment. A lifestyle that is sustainable. As you have learned at the beginning of this post, there is a variety of renewable energy sources. One of their advantages is that there is such a great mix of them that every part of the world should be able to use at least one renewable energy source.

Map showing the amounts of solar radiation reaching the Earth. The highest levels of solar radiation are coloured in dark red, the lowest in beige.

The resource with the greatest potential is probably solar energy. Many people doubt its usefulness and think that buying solar panels is too expensive. Another argument is that (as the map on the right shows) only regions near the equator receive great amounts of solar radiation. People say that the amount of solar energy that can be used can vary a lot from one day to another, and thus the energy supply is unpredictable. Besides, a lot of the energy is lost during transport from the power stations to the consumers. But actually, most people underestimate the progress that has been made in recent years. Scientists have worked on these problems –  and they have improved the technology a lot. According to Greenpeace, buying and installing solar panels has become a lot cheaper. For countries that are located within the tropics where there is a lot of sunshine, it can be cheaper to use solar energy than to pay for sufficient infrastructure to transport electricity from other energy sources into rural areas. Experts also say that covering 2% of the Sahara with solar panels would provide enough energy for the whole world. Just 2%! That’s quite little if you consider the amount of energy that we consume. And there are other deserts that can be used to build solar power plants, for example in the USA, Mexico, India, and Australia. What is more, scientists have developed more efficient ways to transport the energy, so that only very small amounts of it are lost during transport. In my opinion installing solar power stations in the deserts is a good solution because it’s not such a waste of space. This is due to the infertility of the ground and the extreme living conditions which make deserts places that very few humans use for other purposes than producing solar energy.

Solar power plant in the Mojave desert, USA

Of course, this is just an example for using renewable energy in the future. We can use all the other renewable energy sources we have as well, and we can combine them to achieve a higher energy security. People have started to promote renewable energy sources, and we’ve had a good start, but there is still a very long way to go until we can call ourselves independent from fossil fuels. We must transform the world as we know it gradually to succeed and to create a smooth transition from non-renewable to renewable energy. We have to change our economy and stabilize population numbers to keep them on a sustainable level. We need to find a new lifestyle where fossil fuels are replaced by renewable energy sources.

But if we manage to combine our efforts and work together on one big goal, I believe that we can end our dependence on fossil fuels. It will take time and we’ll have to surrender some of the comforts we are used to, but I am sure that the result will be worth it.

So, again I hope that you have learned something new from this post, and that you’ve enjoyed reading. And I want to thank all those of you who have been busy writing some amazing 1000 comments on my blog!