Lecture Outline

• Supply, Demand, and Reserves
• Energy Use:
• Renewable vs non-renewable
• What are fossil fuels and why are they important?
• How are fossil fuels formed and concentrated?
• Reserves and Usage Rate
• Extending the supplies

Announcements

1. Read Chapter 13 in Pipkin text.
2. Strongly encourage web-surfing - astonishing amount of information on gas, oil, coal, new technology, renewable energy such as wind and solar power.
3. Web sites: http://www.eia.doe.gov

Energy: the capacity to do work.

Human's success as a species is largely because of their ingenuity in exploiting energy in myriads of ways.

In 1990, non-renewables (fossil fuels) provided 90% of global energy. 92% in US. Global economy heavily invested in use of non-renewable resource.

FIGURE 1: 1994 US Energy Sources and Uses:  FROM US Department of Energy

Look at figure and notice renewable energy source contribution. Hydropower and wood burning contribute 90% of renewable power. Wind, geothermal, and solar power thus contribute only about 1% of US energy needs at present.

Question: how long before the resource is exhausted and what then?

I. Supply, demand, and reserves: Terminology and concepts

Reserves - already discovered deposits that can be extracted profitably.

Sub-economic or conditional resource - already discovered deposits that cannot be extracted profitably at present price.

Inferred resource - deposits that are likely to exist, but haven't yet been discovered. Can be estimated via statistical means.

Resource price increases or production cost decreases typically lead to increase in reserves because some previously discovered low concentration deposits become profitable.

Increase in commodity price often drives people to conserve, recycle, or use substitutes. Reserves may thus not always increase as prices increase.

II. Energy Use

Energy sources can be divided into two categories.

Renewable energy - provided by resources that accumulate as quickly or more quickly than they are used. Examples: sunlight, hydroelectric.

Non-renewable energy: Provided by resources that do not accumulate as quickly as they are used. Use is not sustainable over long run. Examples: oil, gas, coal, nuclear.

Principal energy use concentrated in generation of electricity (13% globally), generation of heat, and transportation.

III. Fossil fuels : Definition, formation, and accumulation

Fossil fuels - fuels derived from the remains of dead organisms. Examples include coal, oil, oil shales, tar sands, natural gas, and peat.

Hydrocarbons are molecules that incorporate both carbon and hydrogen. When hydrocarbon molecules are exposed to heat, the bonds linking the carbon and hydrogen atoms break. The liberated hydrogen combines with nearby oxygen to form water; the liberated carbon combines with oxygen to form carbon dioxide, and the net energy released by these chemical reactions is positive.

Overhead 1 - Time line of fossil fuel use

• Use of fossil fuels a short-lasting event in human history. Migration to renewable energy forms gaining momentum.
• Rapid depletion of resource that has been accumulating for hundreds of millions of years.

Formation of fossil fuels

Fossil fuels form only under exceptional circumstances. Dead organisms remains normally dry out (i.e. dehydrate) quickly, leaving behind their organic content (i.e. molecules that contain carbon). Normally, oxygen reacts with the organic matter, causing it to oxidize and re-enter environment as carbon dioxide or other carbon-based molecules. However, if organic matter is buried quickly enough or is introduced into an oxygen-poor environment such as lake-bottom water that lacks oxygen, the energy content locked into the hydrocarbon molecules is preserved, and can be released if burned in an oxygen-rich environment.

Oil and Natural Gas (methane) are fossil fuels formed through the accumulation and transformation of the remains of small marine organisms into liquid hydrocarbons. The necessary conditions for the formation of recoverable oil and gas deposits are

Conditions necessary to for form oil and natural gas

• Remains of marine organisms must be buried before oxidation occurs.
• Sufficient time (more than several thousand years) must pass to convert organic remains into hydrocarbon molecules.
• The rock must not be subjected to temperatures high enough to cook away the hydrocarbons.
• Rock containing fluid hydrocarbons must be permeable and porous so that there is sufficient pore space to accommodate the fluid and the fluid can flow through the rock.
• The hydrocarbons must accumulate beneath a geologic trap, which is most often in the form of an impermeable rock layer that prevents hydrocarbons from migrating to the surface and dispersing. Hydrocarbons in permeable rock without trap do not pool into a recoverable deposit.

Study figure of petroleum traps in Pipkin, Page 339

Coal and Peat - fossil fuels formed through the accumulation and transformation of land-based organisms. Details given on page 346 of text.

Tar sands and oil shales - discussed in text. Total energy resource represented by these fossil fuels is astoundingly large, equivalent to several hundred years supply. Not presently economical because of technological and environmental impediments.

• Oil

Presently supplies more energy to global economy than any other fuel. Roughly 25-30%.

Abundant, cheap supplies of oil may continue for 20 to 50 more years, although significant supplies of oil will certainly be available for longer than that for the right price.

Interesting facts:

• Saudi Arabia, with the world's largest reserves of crude oil, could supply the world's needs for only 10 years before total reserve depletion. NOTE: RESERVE, NOT RESOURCE DEPLETION
• The oil that companies hope to find (a 20% chance) in Alaska's Arctic Wildlife Refuge could meet U.S. demand for only 6 months. A very large oil field (i.e. 1-10 billion barrels of oil) constitutes only a few months oil supply at present rates of global oil consumption.
• Middle East has nearly 100 year reserve of exploitable oil at present prices and present production rate; North America has only 10 year reserve. However, NA has enormous sub-economic resource (300 billion barrels or 13 times the reserve) that can be exploited at higher prices. Global reserve has 44 year lifetime at present prices and rate of production.
• Reserve estimate does not take increase in demand and thus increase in production into account. If production is increased to satisfy increased demand, lifetime of reserve decreases.
• If price increases, reserves may increase because companies will report oil fields that are presently held out of production due to low prices.

• Natural gas (methane) (click here for further details about natural gas)

Natural Gas or methane - The fossil fuel of the next 50-100 years.

Lifetime of total resource in U.S. at present use rates is about 65 years. USGS estimates it will require about 1 million new gas wells to pump out the resource.

Why is this the fossil fuel of the future?

• Generates little carbon dioxide when burned, and its energy content can be converted to power very efficiently because as a gas, it burns more completely than oil or coal.
• Proven reserves are increasing rapidly and now stand at 60-100 years. The total resource could last much longer, two centuries by some estimates.
• Over 50 countries have useful supplies, making it a more widely distributed fuel.
• Turbines that burn natural gas to generate power are more efficient than for coal or oil, and power plants can be built in only a couple of years and modularized to supply small and growing markets.
• Natural gas is much more versatile than coal or oil, can be used in 90% of all energy applications with little effort. Home heating and cooling, car fuel, electricity generation, fuel cells... FUEL CELLS are a new technology that convert energy in methane directly to electricity via chemical reactions in small, silent, non-polluting portable cells. They are extremely efficient and non-polluting. Fuel cells are just coming to market. (http://www.i-way.co.uk/~ectechnic/home.html)
• Energy can be converted more efficiently to power and heat with natural gas than with oil or coal. Conversion efficiencies: large coal, oil, or gas burners 35-40% energy content to electricity, 65% to heat and typically lost; gas turbine station - 30% energy content to electricity, 50% to heat, some of which is used, and 20% to run system (i.e., lost); Fuel cell: 40-45% energy to electricity, 35-40% heat used on site, 20% lost running the system).

At present trends, natural gas will overtake oil in the next 10-12 years as the number one globally produced fossil fuel.

Reserves are so abundant in some countries that they are simply flared off and lost. However, globally, an enormous gas rush is on - many tens of billions of dollars of natural gas pipelines and power plants are being built each year to exploit this abundant and relatively clean fuel.

Disadvantage: Methane is a powerful greenhouse gas, so when it escapes during pumping, transport, or use, it contributes to our greenhouse effect. Its also extremely explosive.

• COAL

Coal is our most abundant and yet dirtiest source of fossil fuels. For current or slowly increasing levels of energy use, proven recoverable reserves in U.S. are sufficient to supply all of our energy needs for about 260 years. Globally, we have a 230 year supply of coal.

In the U.S., coal generates 56% of the electricity, and globally, coal generates 44% of electricity.

Advantages:

• Because of ample domestic supplies, our country is not subject to volatile world politics. We have used only a few per cent of our existing reserves.

Disadvantages:

• Burning it generates a lot of CO2, (twice as much as equivalent amount of natural gas), heavy metals, sulfur, and ash, all of which are toxic to the environment,
• Not useful for motor vehicles,
• Mining coal is environmentally destructive

V. Energy Efficiency and Conservation (click here for energy efficiency info)

Ways to extend fossil fuel reserves or reduce our dependence.

• Conservation (i.e., using less)
• Increased efficiency (i.e., extracting more from what we use)

Increased efficiency goes hand in hand with conservation.

Examples: Superefficient Cars, more efficient electrical appliances, better energy-to-power conversion efficiences

Amount of energy to be saved is enormous - energy saved by high-efficiency light-bulbs, if installed for old incandescent types, would equal entire power output of nation's 109 functioning nuclear power plants. Installing variable speed motors in US factories would save more than $100 billion per year in industry power costs . Savings in power costs would pay back for the cost of the new motors in less than 1 year!

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