Energy an overview

Energyan overview

How many different sources of energy can you name?

• Oil• Coal• Natural gas• Biomass

– Biofuel crops– Wood– animal dung

• Solar– Photovoltaic– heat

• Wind

• Nuclear• Fuel cell• Tidal• Current• Wave• Hydroelectric

– Large– Small

• Geothermal

How many are solar based?

• Oil• Coal• Natural gas• Biomass

– Biofuel crops– Wood– animal dung

• Solar– Photovoltaic– heat

• Wind

• Nuclear• Fuel cell• Tidal• Current• Wave• Hydroelectric

– Large– Small

• Geothermal

What is energy, anyway?

• The ability to do work

• That is: gives the ability to move things

• It is force multiplied through a distance

• Key: Energy takes a variety of forms, but all forms can be used to do work.

Some energy units• British Thermal Unit (BTU)

– Amount of energy needed to raise one pound of water one degree F.– Roughly: the energy in a kitchen match– 1 candy bar has about 1,000 BTUs

• Joule– 1,000 joules = 1 BTU– About one million in a donut– Rarely used in polite conversation, but kilowatt-hours are just a fancy way of referring to

joules

• Heat can be equivalent to mechanical energy– 1 calorie = 4.186 joules– 1 calorie raises one gram of water by one deg. C– Food calories are in reality Kilocalories

Power

• The rate of doing work

• One watt = 1 joule/second

• We pay for electricity by the energy consumed, NOT the rate at which it is consumed.

• Usually: kilowatt-hours:

• = 1000 J/sec x 3600 sec = 3.6 x 106 J

Power vs. energy

• Go to the gas station. Fill your tank. Are you paying for the gasoline (energy) or the rate that you pumped the gasoline (power)?

• With electricity, you pay for the energy, not the rate you use it. So, you pay for kilowatt-hours, not kilowatts.

Energy conservationvs

Conservation of energy

• Conservation of energy: 1st law of thermodynamics says ``energy cannot be created or destroyed’’

• Energy conservation: Try to do things using as little (nonrenewable) energy as possible

Entropy

• Energy always deteriorates, becoming less usable

• 2nd law of thermodynamics: energy decays from a more usable to a less usable form– ENTROPY INCREASES

• Usable energy lost as heatemphasizes importance of conservation

Energy is at the root of many environmental issues

• Global warming

• Air pollution

• Sprawl

• Municipal waste (cheap energy means discard rather than reuse)

• Industrial agriculture

• Loss of habitat

•

Fossil fuels

• Formed hundreds of millions of years ago—before the dinosaurs

• From the remains of plants and animals, many tiny

• Cooked – pressure and temperature (as well as starting material) determine the fate

Coal

• The remains of decaying plants from swamps 300 million years ago

• Carboniferous period

Types of coal

• Lignite SOFT

• Subbituminous

• Bituminous

• Anthracite HARD

• Highest in water, lowest in btu/lb

• High water content, slightly higher btu/lb

• Lower water content, higher btu/lb, HIGH in SULFUR

• Lowest in water, highest in btu/lb, low in sulfur, most expensive

• Not coal Coal• 60% carbon 85% C

coal

• Mostly carbon

• A chunk of coal contains practically every other element – Sulfur– Heavy metals

The U.S. . . • . . . is the Saudi Arabia of

coal• In 2004, the US

government estimated that Wyoming had about 42 billion tons of mineable coal in the ground– Enough for the entire US

for about 40 years!

Coal

• Safety problems– Black lung disease– Mine disasters

• Legislation– Surface Mining Control and Reclamation Act

• 1977, required that open pit mines, once left as is, had to be reclaimed.

• Prohibits coal mining in sensitive sites, such national parks, wildlife refuges, etc.

Coal

• ASH = unburned particles– 98% is captured, landfilled– So, 2% released particulates

• SULFUR = in most coal, reacts with oxygen to form SO2 and then in atmosphere to form sufuric acidacid rain

• CARBON DIOXIDE

Oil and Natural Gas

• Oil: forms from microscopic aquatic organisms that die and are buried, absence of oxygen

• Natural gas: forms similarly to oil, but at higher temperatures

Structural trap

• Oil or gas trapped under and above impermeable rock (``cap rock’’)

Oil production: US

• What do you think is happening to U.S. oil production (i.e. the number of barrels of oil produced each day from U.S. wells)?

•

Peak oil

• Pay attention to this: you’ll be hearing a lot more about it.

• Key point: There is a finite amount of oil. At some point, the production of oil—the removal of oil from the ground—will peak and start to decline. That point is now.

• Another way of saying it: peak oil is the maximum daily global production of oil. After the peak, it’s downhill.

Peak oil

•

Saudi Arabia's King Abdullah told his subjects in 1998, "The oil boom is over and will not return... All of us must get used to a different lifestyle."

— Abdullah S. Jum'ah, 2008-

01[119]

``I do not believe the world has to worry about ‘peak oil’ for a very long time.’’ President of Saudi Aramco

”

Implications of peak oil

• What will happen if oil production declines?

• Think about all the things that use oilsee figure 19.11 in the textbook

•

Impacts of using fossil fuels

• All: carbon dioxide – a byproduct of combustion

• Coal: acid mine drainage – minerals in exposed rock interact with water.

• All: habitat destruction –mt.top removal for coal; disruption of habitat for oil/gas -ANWR

• Coal: acid rain• All: air pollution—particulates,etc.

Conserving energy

• Cogeneration– Capturing and using waste heat from other

processes• Sometimes, the heat is used to warm up buildings

in a cold area• Sometimes, the heat is used to boil water to make

electricity

Efficiency

• No process uses energy 100% efficiently– (1st and 2nd laws)

• Typical power plant: 33%

• Incandescent light bulb: 5 %

• Fluorescent light bulb: 20%

Efficiencies why not 100%??

•

Energy input, (BTUs) per person, per mile

• Automobile (driver only) 6530

• Transit bus (9 p.) 4235

• Airplane – commercial 3261

• Commuter Rail(31 p.) 2996

• Carpool 2230

• Motorcycle 1855

• Vanpool (6 p.) 1094

ANWR

• Arctic National Wildlife Refuge

• go to anwr powerpoint