This expedition explores the many ways in which we capture energy and put it to use.
Fossil fuels are natural formations. Produced by the Earth, they are composed of the decay of living organisms, such as plants and animals that have been placed under sustained pressure for long periods of time.
Coal, oil, and natural gas are the 3 most commonly used fossil fuels.
Sea creatures only as big as a pinhead are the origin of oil. Able to convert sunlight into stored energy, as they died and were buried under sediment and squeezed for long periods of time, they formed the fossil fuel.
Prehistoric remains of plants and animals formed peat and became trapped in peat bogs and swamps. These trapped organisms turned into coal after sustaining prolonged periods of pressure and heat along with decay.
Odorless and tasteless, this gas is a hydrocarbon composed of both hydrogen and carbon particles. It is also a byproduct of living organisms that decayed hundreds of millions of years ago.
Nuclear energy is created using a process called nuclear fission. This process involves the splitting of large atoms, such as uranium or plutonium, into 2 smaller ones by slamming another particle, a neutron, into them.
This creates large amounts of heat, which is used to boil water to produce steam. The steam then runs turbine generators that produce electricity.
When a neutron collides with uranium, it causes it to split, releasing heat and 3 more neutrons into the reactor. This causes a chain reaction as these neutrons collide with other uranium atoms, forcing them to begin splitting as well.
There are 2 nuclear reactor types. The Boiling Water Reactor (BWR) directly boils water in the reactor to create steam. The Pressurized Water Reactor (PWR) keeps reactor water under pressure so it can’t boil, using its heat to boil a secondary water supply to create steam.
Neutron absorbing control rods help control the rate of reaction caused by the neutrons hitting the atoms. If too many reactions occur at once, the reactor could explode. Usually made of cadmium and boron, control rods help absorb excess neutrons after an atom is split.
There are a number of ways to utilize geothermal energy but they all have the same source: the Earth! Whether it be hot water in shallow ground, or hot rock found deep beneath the Earth's surface, all of these geothermal sources arise from the heat generated by the Earth.
We use this energy in different ways, from heating buildings to removing snow and even to creating electricity.
Step 1: Cold Water
In order to generate the steam needed to turn turbines, cold water is injected into permeable rock. This special rock has little holes that allow water to pass through.
Step 2: Add Magma
Below the crust of the Earth lies the next layer, a hot liquid rock called magma. The heat from the magma underneath this permeable rock converts the water to highly pressurized steam.
Step 3: Collect Steam
An underground well then taps into that steam. Next, the steam turns the blades of special turbines that are connected to the generators that will actually create electricity.
The steam used to turn the turbines is collected and cooled down, and returned to its liquid form. The water is then reused to start the energy creation process again.
Solar energy is made possible because of our sun. Using a process called photovoltaics, heat and light are captured to create energy. Photovoltaics technology captures sunlight and converts it into direct current electricity, which can be used in many different ways. The heat of the sun can also be captured directly and used.
Available in many sizes, solar panels are used to power everything from toy cars to entire cities. Previously, energy collected from solar panels could not be stored efficiently, however with battery technology improvements, solar energy can be used night or day, rainy or sunny.
Solar panels consist of 2 sides, positively charged and negatively charged.
When directing the sun’s photons into atoms on the negative side (generally made of silicon) electrons are released, creating an electrical current as they travel to the panel’s second layer (usually made of boron).
Solar Thermal Plants
Harnessing the sun’s heat to generate electricity, many large mirrors called heliostats reflect sunlight and focus the beams onto a receiver. A boiler filled with water is found inside the receiver.
The concentrated sunlight heats the water, converting it to steam, which then turns the turbines to create electricity.
Wind energy is a form of mechanical energy. The wind’s kinetic energy spins turbines, which create mechanical energy for electricity. In order for them to work best though, they need a steady wind speed of at least 13 miles an hour.
These structures were one of the first ways in which man harnessed the power of wind. Windmill uses include grinding (or milling) grain and pumping water from wells.
Horizontal Axis Turbines
With its rotating axis parallel to the ground, this wind turbine may face directly into the wind, or away from it. Although they have the most potential for producing large amounts of electricity, horizontal axis turbines can have trouble without a steady wind.
Vertical Axis Turbines
The rotating axis of a vertical axis turbine is perpendicular to the ground, so that it captures wind from all directions. These wind turbines work well in areas that do not have a steady flow of wind in any one direction.
Hydropower, also called hydroelectric power, uses the kinetic power of moving water to make electricity.
Water can be collected from various sources, such as rain, melting snow, streams, rivers, and even the ocean, to turn mechanical turbines that spin a generator, which produces power.
Dams are one way that water powers turbines. By collecting rainwater, melting snow, or water from fast flowing rivers, dams store water in reservoirs. The stored water is then funneled through narrow channels that contain turbines, which create electricity.
Pumped storage is used to regulate power production at hydroelectric plants. It involves pumping water from a lower reservoir (which has already passed through the turbines) back up into a higher reservoir, where it can be recycled back down as more power is needed.
This ancient invention utilized the moving water in rivers to turn water turbines. These water turbines, much like our modern turbines, were connected to shafts which could in turn rotate other objects, such as millstones for grinding grain.