2.5.2 - The Lithosphere (KQ5): Energy Resources

Energy is a major part of our lives.  In the past 150 years, as we've gone through the industrial revolution and beyond, our use of energy and energy resources has skyrocketed.  We power our homes, technology, schools and businesses, transportation, you name it...things would collapse if we lost our energy. It takes resources to generate the energy we use.  We have been very reliant on non-renewables, like coal for our power plants and oil for our transportation, but with the major depletion and pollution issues associated with them, we've been turning our eyes more toward cleaner energy sources that are renewable like solar and hydroelectric power.

In this blog, I will give you information on both renewable and non-renewable energy sources, with pros and cons.  You will be getting more information and sharing with the class via a poster project as well.

Before we get started with that, I want to draw your attention to the concept of net energy.  Net energy is the amount of high-quality usable energy available from a resource after the amount of energy needed to make it available is subtracted.  Basically, take out the amount of energy spent mining, refining, and processing, and the net energy is left over.  The following graph shows both non-renewable and renewable net energy.  It is shown in terms of net energy ratio, basically anything over 1 gives off that many times more energy than it takes to make it.

Surprised?  Coal is #1...by far!  Think about it, all you have to do is dig it out and burn it.  No fancy equipment, no refining, not a big transportation issue because it's solid.  BUT, it is non-renewable, and the dirtiest one up there.  Thus, while extremely energy efficient, alternatives need to be found.

Following is a graph showing how energy use varies between the US and the rest of the world.  While we have the technology to lead the world, we are lagging behind in a lot of ways.  Hopefully this section will help you to understand what we can do better.

We will be going over a lot of types of energy, so here is a graphic that shows how a lot are extracted:

Nonrenewable Energy Resources

Oil

Crude oil, the stuff that's actually drilled out of the ground, is a thick mixture of a bunch of hydrocarbons (Yay Chemistry!).  It was made from dead organisms (plants/animals) that decomposed and were put under pressure over time. The energy from the living things condensed and formed the energy-rich oil.  Oil, along with coal and natural gas, are referred to as fossil fuels, because they come from once-living organism remains (fossils). These hydrocarbons have different densities and are distilled at different temperatures in a process called fractional distillation.  We tend to think about oil as only being for transportation, but look at all the ways it can be used in the following diagram of a fractional distillation tower.

It's crazy the amount of stuff we get from oil.  Like I said, we'll be hearing more during the poster presentation.  Here are a list of advantages and disadvantages to using oil.

Oil Sands and Oil Shale

Oil can be found in sand and rock (shale) in different places around the globe.  It is way more costly to get because of the hardship of extraction, but technology is making it easier.  In fact, the massive amount of oil sands in Canada is the source of oil that's planned to be transported in the controversial Keystone XL pipeline.

Natural Gas

Natural gas is in the gaseous state (mostly methane) and is found usually above liquid oil.  It's being used more and more, and while it burns cleaner than oil, it still produces carbon dioxide and pollutants.  It's an intermediate alternative to oil, but still non-renewable.

Coal

Coal makes up the majority of the fuel used for electricity generation in the US and around the world.  Like oil, it is a fossil fuel that forms over time after living things die.  Here is a diagram of  different types of coal that are extracted based on it's level of formation.

Coal burns very dirty, but the US has implemented much stricter regulations over the years to deal with the emissions.  China, on the other hand, uses more coal than the US, Japan, and Europe combined, and has less regulations.  This has led to a lot of health problems there.

Before we look at advantages and disadvantages, I wanted to give you a diagram of how we turn coal into electricity...it's pretty simple really.  Burn coal, heat water, turn into steam, turn a turbine, generate electricity.

Nuclear Energy

Woah...wait a minute...I thought Nuclear was clean?  Why is it a non-renewable resource?

First off, just because something is 'clean' doesn't mean it's renewable.  Yes, Nuclear is clan when it generates electricity, but to get the electricity, we have to mine and enrich Uranium.  That process is very energy intense, in fact making the net energy of Nuclear extremely low, as shown below.

Plus, nuclear is very susceptible to large scale accidents like those seen in Chernobyl and Fukushima.

Just an FYI...nuclear power plants work just like coal power plants, but instead of burning coal, radioactive uranium starts to decompose, giving off massive amounts of radiation and heat, boiling water, turning the turbines, etc.  Here are diagrams of both the nuclear fuel cycle and a reactor, followed by the advantages and disadvantages of nuclear power.

Stop Here Day 1

Renewable & Alternative Energy Resources

Energy Efficiency Options

We wast massive amount of energy in our normal production and distribution of electricity, in our transportation, and even in our homes.  Waste happens during production, transportation, and by machines themselves.  Look at the total energy balance for our electricity below, and you can see what I mean.

The first step to reducing fossil fuel and non-renewable energy use is to make those systems more efficient.  Some waste is unavoidable (think Newton's 2nd Law), but 43% is what we think we can save.  How?  Look at a few of the options below.

The Grid - Our current electrical system basically uses a giant connected series of wires to power plants and buildings.  It has major energy losses along those lines.  Ways to improve would be by installing smart grid systems, which would monitor electricity, regulate when and where power systems went on, and integrate micro power plants that aren't so far away from the destinations.

More efficient buildings and houses - Many buildings and houses were not built with energy efficiency in mind; thus, they waste a lot of heating and cooling costs which could be save by:

• Insulating and plugging leaks
• Using energy-efficient windows
• Stopping other heating and cooling losses
• Heating houses more efficiently 
• Heating water more efficiently
• Using energy-efficient appliances
• Using energy-efficient lighting

The following diagram gives a great idea of many savings that can be done in regular homes.

Green Roofs - Many buildings in big cities are putting vegetation on their roofs.  It helps not only with CO2 sequestering, but provides natural insulation to cut down on heating and cooling losses.  There is actually a green roof on top of the restrooms in Island Park near Marina Jack.  Check it out next time you're there!

Fuel Efficiency in Transportation - While we have made advances here, increasing the efficiency of our transportation still lags behind most other countries.  By turning to hybrid, electric, and smaller cars with more efficient engines, we could really cut down on our oil consumption.  Remind me to spend a little more time explaining hybrid and electric advantages in class.

Here is a list of advantages of reducing energy waste:

Now, let's take a look at the renewable, alternative energy sources. There is no one answer to replacing non-renewable fuels.  All alternatives won't work in all places...and they all have their advantages and disadvantages.  It'll be a combination of ideas that is able to fix the problem.

Solar

Every energy source starts with the sun.  Even fossil fuels originally had their energy provided by the sun to grow themselves or the food that they either before they died.  So, getting energy directly from the sun is an obvious solution.  There are a few types of ways we harness solar energy:

Passive and Active Solar Systems

Both of these systems involve using direct sunlight for single buildings/houses.  Passive systems use special windows/vents to provide heating in the winter and cooling in the summer just from the sun.  Really cuts down on electricity use.  Active systems use solar collectors on rooftops to heat a fluid to use in water heaters, air conditioners/home heaters, and in Florida many times, pool heaters, saving major amounts of electricity use.  Both systems are shown below followed by advantages/disadvantages.

High Temp Solar Collectors

These systems use reflective mirrors to concentrate heat from the sun on a single point, usually a pipe, that then provides the heating power for power plants.  Advantages/disadvantages are shown below of these types of systems.

Solar Photovoltaic Cells

Also known as PV cells, this is what most people think of when they think of solar energy.  Photons (light) from the sun is absorbed, 'excited' electrons, and provides electricity directly from the cell.  They're getting better, but are still pretty inefficient and costly.  They can be put on rooftops or in large fields.  A couple types and the trade-offs are shown below.

Hydropower

Water is very heavy, and the use of falling or flowing water to turn wheels has been around a very long time.  We now use it to turn turbines to generate electricity.  We have developed technologies to harness wave power, but of course, this would only work for coastal areas.  Same with tidal power (getting the water flowing in and out during tides).  The most widely used method is the construction of dams.  A dam is basically a wall placed in a river.  Upstream, the river floods into a still water reservoir (lake).  Water flows downstream at a much slower rate, because it falls through the inside of the wall, turning turbines, generating electricity.  It's basically free energy (minus the operating and building costs), but has major environmental impacts on the surrounding ecosystem.  We will discuss these more in the hydrosphere unit.  For now, from an energy standpoint, take a look at the trade-offs below.

Wind

Predictable high winds aren't a common occurrence everywhere, but where they are, wind energy is a no-brainier.  Large windmills do the heavy lifting, with no additional parts needed.  They can be noisy and cause harm to birds, but those problems are being addressed with some really cool new technologies.  Here is a diagram of different types and the advantages/disadvantages.

Biomass/Biofuels

Biomass is basically anything living.  So using biomass for fuels, is burning things like trees and plants for fuel.  They burn pretty dirty and are not nearly as efficient or energy-dense as coal.  Plus, in order to be used sustainable, they need to be regrown at the rate you use them.  Trade-offs are shown below.

Biofuels are liquid fuels made from biomass, like ethanol made from corn and diesel made from used vegetable oil.  Trade-offs of biodiesel and bioethanol areshown below.

Geothermal

Geothermal energy is literally 'energy from the ground.'  It can be utilized in multiple ways, including in single buildings and large-scale plants.

For sing,e buildings, pipes connected to home heating and cooling units can be run under the ground, where the temperature is always constant.  In the winter, the fluid in these pipes is warmer than the outside air and in the summer, the fluid is cooler than the outside air.  By running them through the heating/cooling systems, it reduces the amount of energy needed to run.  Here's an example of what that looks like.

Large-scale geothermal plants will use pockets of hot water found under the earth.  These are typically around geyser locations.  This hot water will come out as steam, thus no need for burning.  These are great where available, but do run out after time.  Places like Greenland with massive potential for large-scale geothermal plants are being considered to produce hydrogen, which is very intensive, and you will learn about in the next area.  Below are the advantages/disadvantages of geothermal energy.

Hydrogen

Hydrogen is a great source of fuel, because it can be put through a fuel cell along with oxygen from the air and electricity is generated, with the only product being water vapor!  The process is shown below.

 Hydrogen cars are already on the road, but the reason they haven't been in mass production is that hydrogen is very expensive and energy-intensive to generate (usually electrolysis from water) and it is very had to store, since it is a gas.  Technologies are being worked on, and you can see the trade-offs below.

Putting it all together

So, like I said before, there's no one answer to the replacement of non-renewable fossil fuels.  It will need to be a gradual shift, with multiple system in place.  Much more research is needed, but the answer will be a smart, energy efficient grid, with a combination of different types of energy production and less large-scale plants.  A diagram of this kind of idea follows.

That's ideal, but integrating with already existing fossil fuel systems is the first step to a cleaner and sustainable future.

Graphics obtained from Living in the Environment, 2009, Miller & Spooner