# Pages Colby Carbon Footprint What is Energy Page History

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What is energy?
•    Merriam-Webster Definition  of Energy: a fundamental entity of nature that is transferred between parts of a system in the production of physical change within the system and usually regarded as the capacity for doing work
•    According to the Law of Conservation of Energy, energy cannot be created or destroyed, although it continually changes forms.
•    There are many different units for measuring energy.  The SI unit for measuring energy is Joules (j).
http://www.unit-conversion.info/energy.html
•    Everything we do uses some form of energy.
Example: Driving to work in a sedan consumes 3 MJ per passenger-mile traveled.

•    Everything we own and use, from the clothes we wear to the food we eat requires energy to manufacture or produce.

How Do we Make Energy?
Coal, Natural gas, and nuclear energy are used to make heat to convert liquid water to steam.

Steam spins the turbine.  Within the spinning turbine a big magnet is rotated around a length of wire, creating a magnetic field that electrifies the wire. Electricity goes out of the wire to transformers, and from transformers to us!

Instead of steam, wind power or running water can be used to spin the turbine.

How Do We Measure Energy?

Energy is measured in joules, the derived SI unit to find as     m2·kg·s-2, or applying the force of one Newton over the distance of a meter.

A joule measures energy in forms of heat, electricity, and mechanical work.

Although we measure energy use in different forms in our daily life, each system of measurement can be converted back into joules.

For instance, power companies tell us we use a certain number of kilowatt hours each month. However, one kilowatt hour is actually 3.6 MJ.

We also measure the energy automobiles use by measuring how many gallons of gas each consumes. There are 131.845 MJ of energy consumed for each gallon of gas used.

To heat our houses we use heating oil. One gallon of heating oil burned represents 146 MJ used.

How do we sell energy?

If energy is the ability to do work selling energy is really just selling work. To do this one must gather resources, which eventually become products or services capable of producing work. Because of the law of conservation, energy already exists; selling energy pertains to harnessing it and releasing it in its most efficient form.

Fuels:Renewable: Solar, Wind, Tidal, Hydro.

Non renewable:  Gasoline, Natural Gas, Food, Geothermal*

Nuclear: Fission, Fusion, Pebble.

Services: Heat, electricity, cooling, labor,

Products: Generator, tools.

* Depending on rate of consumption geothermal energy can be renewable.