While the total amount of energy can never be changed, energy can be transformed from different physically manifest forms. For example, thermal energy can be converted into mechanical energy through the processes that occur inside a steam turbine (water is heated up which then creates pressure force that turns a rotor). That mechanical energy can then be converted into electrical energy by way of a dynamo (the rotational action spins a coil of conducting material within a magnetic field).

Scientists like Sir Charles Parsons and Michael Faraday discovered these conversion techniques by understanding the physical properties of materials, how they interact with each other, and how they change when heat energy is given to them.

Solar radiation energy can be converted directly into electrical energy with the use of semiconductors that display the “photovoltaic” effect (solar energy knocks off free electrons from the material). Nature has evolved photosynthesis to convert solar radiation energy into chemical energy.

When talking about electrical energy that is used for a purpose, like powering a house or a factory, we have to talk in terms of power over a duration of time, hence the term kilowatt-hour(KWh) that arrives on your electric bill from the utility company. You can find out the capacity of your house to use energy by adding up all of the watt rating of all of your appliances, lights, etc. (everything with a wire running to it).

This would be measurable in watts. For example, say that you add everything up and it comes to 2,000 watts. If you turn everything on and use it at its maximum setting for one hour you would find that you used 2.0 kilowatt-hours of electrical energy.

The same is true for an energy generation system like a solar panel or a wind turbine. The rated capacity of the equipment might be 10 kilowatts. If it runs at peak capacity for one hour, then it would generate 10 kilowatt-hours.

Electrical Generation
How much energy does contemporary life consume?

A quick understanding of how energy is created and consumed (and lost to heat through inefficiencies in conversion systems) can be gained by studying the Sankey Diagrams created by John Ziagos at the Energy & Environment Directorate at Lawrence Livermore National Laboratories.

The above diagram is expressed in British Thermal Units
(1 quad = 1,000,000,000,000,000 BTUs). One BTU is roughly the amount of energy required to raise the temperature of one pound of water one degree F. 1 BTU = .0002931 kilowatt-hours so the 12.77 quads end use equals about 3.74 trillion kilowatt-hours (or 3,743 terawatt-hours).

You can see that the ratio of energy losses to useful energy is nearly 2:1. We have to generate twice the energy we need as a result of waste and inefficiencies in the systems that generate our power and the end uses that convert it to useful work.

Renewable Energy Sources
Another thing that is helpful to note from the Sankey Diagram is that 95% of our energy use is dependent upon fossil fuels or nuclear energy. These sources of energy rely on the extraction of non-renewable resources from the earth: chemical energy or nuclear energy that has been stored by natural processes into geological formations over millions of years. When we run out of these resources, they are gone for good. We can’t just make more.

And as the more accessible deposits of oil, coal, natural gas, and uranium are depleted through conventional drilling and mining, the deeper and less accessible deposits will require increasingly dangerous and environmentally destabilizing methods in order to reach them.

Estimates vary on how long we have for each. Remaining supply at current consumption of uranium has been estimated by the European Commission to be around 42 years and by the uranium mining industry at 80 years. We have already reached the point at which conventional crude oil is getting difficult to extract from known proved reserves. This is requiring deeper ocean wells and sophisticated lateral drilling technologies.

The higher price of oil is also increasing the economic viability of more costly unconventional sources of oil leading to projects such as the Athabasca Oil Sands in Alberta which require clear cutting and removal of “overburden” and open pit mining which have obvious disastrous effects on the environment. Such unconventional methods also require large volumes of fresh water for extraction (four cubic meters of water to extract one cubic meter of heavy oil).

Accelerating a shift away from dependence on non-renewable sources of energy is good public policy for another reason too—the polluting effects of fossil fuel combustion. There is general agreement among climate scientists that carbon dioxide (CO2) released into the atmosphere from the burning of coal, oil, and gas are contributing to changes in global weather patterns, natural ecosystems, raising the average temperature of the planet, acidifying the oceans, and contributing to a steady rise in ocean levels.

An excellent resource for more information about the levels and effects of CO2 in the atmosphere can be found at 350.org. And for the complete assessment of the intergovernmental panel on climate change (IPCC), click here.

 

In order to better figure out how we can help to make a transition to renewable sources of energy, it helps to have an understanding of how much energy we need to produce to satisfy the demands of contemporary life.
On the next page in this section you'll read more about consumer energy needs and electricity production and distribution.

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