As turbomachinery engineers, it is not always easy to tell non-technical folks what we do. If we start with “I design turbines,” the first thing most people think of are those giant wind turbines, and we are stuck with the nickname “wind guy/gal”. What we do is far more complex than putting 3 blades on a stick and confusing bystanders with why the turbine is rotating on a seemingly windless day; and don’t even get me started on the claims that wind turbines are a non-visually pleasing ploy from the government to make use of our taxpayers money.
Okay, maybe I will get started on those topics, but not in this series. Today, I am introducing a new series of blog posts related to clean energies and how turbomachines tie in with this not-so-novel concept making a lot of noise nowadays.
Throughout this series, we will be discussing the different “clean” technologies in power generation which people have been using for hundreds of years, some more recent “hipster-y” applications, and look at what could make a difference in tomorrow’s world. These short posts will cover general and practical information, which students as well as seasoned engineers can use to better understand the topic at hand. Some articles/parts will be more technical than others, and no matter what your current level of proficiency, you will be able to pick out some useful takeaways.
As an introduction to the topic, today’s post will look at what clean energies are and where they come from.
Nowadays, the words renewable and non-renewable are everywhere, but what do they mean? Renewable energy comes from a source that cannot be depleted. (Sure, the sun will burn out in about 5 billion years, but when that happens, we will all be long gone.) Non-renewable energy comes from a finite resource. These commonly accepted definitions lead to the popular misconception that clean energy equals renewable energy. This is partially true and partially untrue. I’ll explain in a minute. Some examples of renewable and non-renewable energy sources will help.
Renewable energy resources include:
- Biomass (since we have a continuous supply of waste residues to burn up with no end in sight)
Now let us have a look at some non-renewable energy sources:
- Fossil fuels (oil/petroleum, natural gas, coal)
- Nuclear fuels (radioactive metals such as uranium and plutonium)
These non-renewable sources are all natural (non-artificial). These resources are being consumed much faster than they can be produced (either naturally or artificially), and therefore are referred to as non-renewables. According to the International Energy Agency or IEA, around 78% of the world used non-renewable sources for electricity generation in 2013.
In that same time frame, the IEA reports almost 22% of the world used renewable energies for electricity generation. That being said, this number is an average and does not differentiate between countries which make much more use of renewable energy sources. For example, Iceland has been running reliably on almost 100% renewable energies for about a decade while Portugal just reached renewable sustainability in March 2018 after years of concerted efforts. Other countries to have reached 100% renewable energy generation include Albania, Bhutan, Mozambique, Norway, Paraguay, and several others.
Now let us look at the definition of clean energies. The clean designation simply relates to energies that do not pollute the atmosphere when used. Looking back to our previous examples of energy sources, we can mark which fit this description and which do not.
- Solar – Whether we put a solar panel on our roof or not, there are no detriments to the environment after installation making it clean.
- Wind – There are no detriments to the environment after installation so this is clean as well.
- Tidal – No environmental impact after installation beside fewer surfing opportunities.
- Geothermal – Heat is being released from the Earth crust. Whether we choose to capture it or to let it escape to the atmosphere, the results on the environment are the same.
- Biomass – This takes energy from the combustion of plant waste, wood chips, organic debris, etc. that produce emissions even though they are currently considered “carbon neutral” and remains debatable.
- Fossil fuels – It is well known that these pollute through post-combustion emission of carbon dioxide, NOx, SOx, so they are not considered clean
- Nuclear fuels – This is where the most confusion exists. When nuclear power is used there is no detrimental impact on the surrounding, but the post-use storage is where things get much more complicated. The details of the process will be covered in a different post.
So now armed with the outline of this blog posts series as well as basic definitions, we can look more in-depth at a particular topic in the next post.