Energy - Wind Energy: Renewable Energy and the Environment - page 14

problems, especially for today's children. If environmental problems affect someone else today or
in the future, who pays? The estimates of the pollution costs for generation of electricity by coal
range from $0.005 to 0.10/kWh.
Physical economics is the energy cost and efficiency of the process, energetics. Others refer to
energetics as energy returned on energy invested. A system for producing energy must be a net
energy gainer. What is the energy content at the end use versus how much energy is used in the pro-
duction, transport, and transmission? Therefore, the energetics of the process has to be calculated
over the life of the system, and the energetics must be postive.
There are fundamental limitations in nature due to physical laws. In the end mother nature
always wins, or the corollary, pay now or probably pay more in the future. On that note, we should
be looking at life cycle costs, rather than our ordinary way of doing business—low initial costs and
then payments over time.
Finally, we have to look at incentives and penalties for the energy entities. Each energy entity
wants incentives (subsidies) for itself and penalties for its competitors. Incentives come in the form
of reduced or no taxes, not having to pay social costs on a product, and the government paying for
research and development, while penalties come in the form of taxes and environmental and other
regulations. It is estimated that we use energy sources in direct proportion to the incentives that the
source has received in the past. There are many examples of incentives for fossil fuels and nuclear
power. At one time in the United States, there was a hugh incentive for the production of oil, a 27.5%
depreciation allowance taken off the bottom line of taxes.

2.2 DEFINITION OF ENERGY AND POWER
To understand renewable energy and the environment, the definitions of energy and power are needed.
Work is the force on an object moved through some distance. Work is equal to force times distance:

W F * D , Joule (J) Newton (N) * meter (m) (2.1)

A number of symbols will be used, and problems can be solved using personal computers,
spreadsheets, and calculators. Examples are supplied for illustration and understanding.
Many people have a mental block as soon as they see mathematical symbols, but everybody uses
symbols. Ask any person what piano means and he or she understand the symbol, but to a South
Seas islander, a piano is “a big black box, you hit him in teeth and he cries.” By the same token,
Equation 2.1 can be understood as a shorthand notation for the words and concepts written above it.
To move objects, do work, and change position of objects requires energy, so energy and work
are measured by the same units. Some units of energy are Joule, calorie, British thermal unit (BTU),
kilowatt-hour (kWh), and even barrels of oil.

Calorie amount of energy required to raise 1 g of water 1°C
BTU amount of energy required to raise 1 lb of water 1°F
Some conversion factors for energy are:
1 calorie 4.12 J
1 calorie kilocalorie 1,000 calories, the unit used in nutrition
1 BTU 1,055 J
1 barrel of oil (42 gallons) 6.12 * 10 9 J 1.7 * 10 3 kWh
1 metric ton of coal 2.5 * 10 7 BTU 2.2 * 10 10 J
1 cubic foot of natural gas 1,000 BTU
1 therm 10 5 BTU 100 ft 3 of natural gas
1 quad 10 15 BTU
1 kWh 3.6 * 10 6 J 3.4 * 10 3 BTU
1 kW 1.33 horsepower