Introduction to Physical Science: Energy and Fuels Energy is defined as the capacity or power to do work, such as the capacity to move an object (of a given mass) by the application of force. Energy can exist in a variety of forms, such as electrical, mechanical, chemical, thermal, or nuclear, and can be transformed from one form to another. It is measured by the amount of work done, usually in joules or watts. All known forms of energy can be converted from one form to another. The Law of Conservation of Energy says that energy can neither be created nor destroyed, but only converted.
For example, a motorcycle converts and utilizes many forms of energy including Kinetic and Potential energies. An electrical current of energy surges to the motorcycle starter creating mechanical energy as it spins, eventually sending a spark to the spark plug igniting a small amount of gasoline (chemical and thermal energy), creating an explosion in the piston chamber. When the piston rotates after this conversion of energy, it turns a crankshaft creating a rotational force of mechanical energy sending this rotation to the transmission, which allows the motorcycle to spin the back wheel.
Exhaust from the chemical and thermal reactions occurring release from the muffler, creating sound energy. Upon moving, the chain spinning creates mechanical energy and the decompression of the springs change from potential energy to kinetic energy. In a matter of mere seconds, a multitude of energy conversions have taken place, right under your rear end. Fossil fuels are organic remains of biological life forms such as plants and animals that decompose under immense heat and pressure.
The process creating fossil fuels results in coal, petroleum and natural gas, three sources of energy that are flammable and found naturally in the Earth. Fossil fuels are considered a nonrenewable resource because they take millions of years to form. However, fossil fuels are highly attractive sources of energy due to their availability and usage. Coal is a solid energy form. It is mined from the ground and processed to clean dirt, rock, ash and other impurities and then transported for the market. Petroleum, or oil, is a liquid found deep underground.
Petroleum is pumped to the surface and sent to refineries via pipelines, vehicles or ships. Petroleum is used to make gasoline, kerosene and plastics. Natural gas is a gas made of methane or mercaptan and found underground. Natural gas is easily transported by pipeline to cities or underground reservoirs until needed. Natural gas is used as a heat source to make products. It is also found in fertilizer, photo film and insect repellants. All three forms of fossil fuels are easily transported, have vast utilization, low manufacturing costs and have production ability for derivative products.
Alternative energy sources to fossil fuels include solar power (solar panels, solar water heaters), wind energy (windmills, sailboats) geothermal energy (heat from within the Earth), biomass (tree branches, manure, yard clippings) ocean energy (kinetic energy via waves and tides) and nuclear energy (splitting an atom releasing heat based energy). Biomass energy is physical matter made of plant material and animal waste, and is the oldest source of renewable energy, having being used since the discovery of fire.
Biomass is used when wood debris is burned heating water and turning it into steam, or in co-firing (using biomass alongside a coal burning facility, utilizing less coal). Biomass has many environmental advantages, such as reduced air pollution and lower carbon emissions. Biomass is very renewable, having the ability to be grown, assisting with soil quality, erosion and natural animal habitats. With the ability of biomass to be grown locally, areas that once had to import fuels can become more financially stable and independent and more energy efficient.
The way biomass is harvested can prove harmful, either degrading soil or destroying habitats. Geothermal energy is heat from the Earth used as an energy source. Geothermal energy can be used for heating, or used to create turbine power, or using ground-source heat pumps (used to cool and heat buildings). Geothermal energy is very clean and natural, and is sustainable. Unfortunately, geothermal energy is connected to discrepancies below the Earth’s crust, such as fault lines and areas more prone to seismic activity. Careful planning and project management are critical.