High Energy Society Why do we care about energy?

What is Energy Energy is the ability to do work. Energy is the ability to do work. Stuff that enables us to move an objectStuff that enables us to move an object Faster movement needs more energy Faster movement needs more energy Heavier object needs more energy Heavier object needs more energy We measure energy in Joules (J) We measure energy in Joules (J) It takes about 200 J to do one deep knee bend It takes about 200 J to do one deep knee bend

Other Units of Energy 1 Btu = 1055 Joule 1 Btu = 1055 Joule 1 calorie = Joule 1 calorie = Joule 1 Calorie = 1000 calorie = 4186 J 1 Calorie = 1000 calorie = 4186 J 1 kWh = 3,600,000 Joule 1 kWh = 3,600,000 Joule

Energy and Power POWER is the rate of using energy. Something that is powerful uses a lot of energy quickly. POWER is the rate of using energy. Something that is powerful uses a lot of energy quickly. Power = Energy/Time Power = Energy/Time This is a Rate Equation This is a Rate Equation We measure power in watts (W) We measure power in watts (W)

Energy and Power Doing deep knee bends at the rate of one every 2 seconds uses energy at the rate of 100 W. Doing deep knee bends at the rate of one every 2 seconds uses energy at the rate of 100 W.

Energy and Power Doing deep knee bends at the rate of one every 2 seconds uses energy at the rate of 100 W. Doing deep knee bends at the rate of one every 2 seconds uses energy at the rate of 100 W. It would take the same amount of energy to do 10 deep knee bends in 20 min as it would in 20 sec, but by doing them in 20 sec, you use energy at a faster rate. It would take the same amount of energy to do 10 deep knee bends in 20 min as it would in 20 sec, but by doing them in 20 sec, you use energy at a faster rate.

Energy and Power Common unit of power is a kilowatt (kW). 1 kW = 1000 W. Common unit of power is a kilowatt (kW). 1 kW = 1000 W. Energy = Power x Time Energy = Power x Time Common Unit of Energy = kWh (kilowatt-hour) Common Unit of Energy = kWh (kilowatt-hour) 1 kWh is the amount of energy you would use if you consume energy at the rate of 1 kW for 1 hr. (10 people doing deep knee bends for an hour.) 1 kWh is the amount of energy you would use if you consume energy at the rate of 1 kW for 1 hr. (10 people doing deep knee bends for an hour.)

When you pay your electric bill the quantity is “kWh”. What are you paying for? A. I’m paying for energy B. I’m paying for how fast I use energy

Energy and Power Because a watt is already a rate it is incorrect to say “watts per hour” or “watts per year” Because a watt is already a rate it is incorrect to say “watts per hour” or “watts per year” 1 hp = 746 W 1 hp = 746 W

Why do we care about energy? Energy provides us with Energy provides us with Necessities Necessities Food, heat, shelter, waterFood, heat, shelter, water Conveniences Conveniences Dishwasher, automobile, entertainmentDishwasher, automobile, entertainment The more energy we have available to us, the more comfortably we can live The more energy we have available to us, the more comfortably we can live

Why do we care about energy? Energy use is strongly correlated to standard of living (as measured by GDP per capita.) Energy use is strongly correlated to standard of living (as measured by GDP per capita.) For most of history we could rely on our own body or animals to do work. This is a few hundred watts of power at most. For most of history we could rely on our own body or animals to do work. This is a few hundred watts of power at most.

Today in the US we consume energy at a rate of 13 kW per person. Today in the US we consume energy at a rate of 13 kW per person. You may think of this as having 130 “energy servants” doing work for you 24/7. You may think of this as having 130 “energy servants” doing work for you 24/7. Typically less wealthy nations have a lot fewer “servants” Typically less wealthy nations have a lot fewer “servants”

GDP vs. Energy Use

GDP vs. Energy Use Trend is Linear

We are doing better on a GDP per kWh basis.

Energy End-use energy End-use energy Energy actually consumedEnergy actually consumed Cars, homes, factories, etc.Cars, homes, factories, etc. Primary energy Primary energy Fuel energy or energy flow plus transportation energyFuel energy or energy flow plus transportation energy

Energy Use By Sector Electric Utilities40% (1/3) Transportation28% (1/3) Industrial/Residential And Commercial 32% (1/3)

Energy Source By Sector Electric UtilitiesCoal (46%) TransportationPetroleum (93%) Industrial/Residential And Commercial Natural Gas(52%)

Where does our energy come from? Approx 81% from fossil fuel

Which of the following is NOT one of the three basic energy sectors in America 1. Transportation 2. Electrical Generation 3. Industrial Residential and Commercial 4. Heating

The primary energy sector that uses coal is 1. Electrical Generation 2. Industrial Residential and Commercial 3. Transportation

The primary energy sector that uses petroleum 1. Transportation 2. Industrial Residential and Commercial 3. Electrical Generation

Oil Supply and Demand

How Much Is There? Proven Reserves: Proven Reserves: Resource that we know is thereResource that we know is there We can extract it at current prices with current technology.We can extract it at current prices with current technology. We can increase Proven Reserves by We can increase Proven Reserves by 1) Finding new reserves. 2) Improvements in technology 3) Changes in economic conditions

Unproven Reserves: Unproven Reserves: We think that it is there based on testing/experienceWe think that it is there based on testing/experienceOR We know that it is there but it is too expensive to extract with current technology/economics.We know that it is there but it is too expensive to extract with current technology/economics.

Note: We never totally extract all of the energy, it just gets too difficult to get after a while. Note: We never totally extract all of the energy, it just gets too difficult to get after a while.

How Long Will It Last ? Simplest analysis is Rate Equation Simplest analysis is Rate Equation Straight-line modelStraight-line model If we know (or can guess) how much we started with (Q  ) and we know the rate we are using it (R) and how much we have already used (Q u ) If we know (or can guess) how much we started with (Q  ) and we know the rate we are using it (R) and how much we have already used (Q u ) Time = (Q  -Q u )/R Time = (Q  -Q u )/R

How Long Will It Last ? Rate Equation doesn’t take changes in use rate into account Rate Equation doesn’t take changes in use rate into account How long = Amount remaining/Rate How long = Amount remaining/Rate Similar to Simple interest - Interest on principle only Similar to Simple interest - Interest on principle only

Poor approximation because it does not take into account changes in rate of use. Poor approximation because it does not take into account changes in rate of use. The demand for energy has been constantly increasing so rate equation time is probably too long The demand for energy has been constantly increasing so rate equation time is probably too long

Exponential Change Amount of change depends on current amount. Amount of change depends on current amount. Similar to Compound interest – interest on principle + interest Similar to Compound interest – interest on principle + interest

YearAmount Interest Total 0$1000$100$1100 1$1100$110$1210 2$1210$121$1331 3$1331$133$1464 4$1464$146$1610 5$1610$161$1771 6$1771$177$1948 7$1948$195$2143 8$2143 Note: Money had just about doubled after 7 years. If we had just added $100 per year (constant rate) we would have only had $1700 after 7 years.

Doubling Time In general, if our percentage growth per unit time is P (%/unit time) then the time for our initial quantity to double is DT where: In general, if our percentage growth per unit time is P (%/unit time) then the time for our initial quantity to double is DT where:DT=70%/P Example: If P=10%/year then DT = (70/10)years =7 years

Between 1960 and 1970, US energy consumption grew by 45% Between 1960 and 1970, US energy consumption grew by 45%

What is P in the doubling time expression? A. 45%/yr B. 4.5%/yr C. 9%/yr D. 10%/yr

How long would it take U.S. energy use to double? A. 4.5 yr B. 10 yr C yr D. 18 yr

Between 1960 and 1970, US energy consumption grew by 4.5%/yr. This would mean energy use would double in only 70/4.5 =15.5 years! Between 1960 and 1970, US energy consumption grew by 4.5%/yr. This would mean energy use would double in only 70/4.5 =15.5 years! With constant rate if we double our reserves, we double their expected life. With exponential growth, doubling reserves will only add a short amount of time. With constant rate if we double our reserves, we double their expected life. With exponential growth, doubling reserves will only add a short amount of time. Obviously exponential growth in energy demand CANNOT go on for very long. Obviously exponential growth in energy demand CANNOT go on for very long.

If we start with $1000, approximately how much money would we have in 14 years if it gains interest at 10% per year? 1. $ $ $ $8000

Hubbert Analysis Production of a natural resource follows a bell-shaped curve with time Production of a natural resource follows a bell-shaped curve with time Initially applied to petroleum production Initially applied to petroleum production

Rationale Based on finite amount of resource Based on finite amount of resource

Rationale Initially, development of a new resource shows a period of rapid growth. Easy access, addition of infrastructure Initially, development of a new resource shows a period of rapid growth. Easy access, addition of infrastructure

Rationale Based on finite amount of resource Based on finite amount of resource Initially, development of a new resource shows a period of rapid growth. Easy access, addition of infrastructure Initially, development of a new resource shows a period of rapid growth. Easy access, addition of infrastructure As high quality, easy to find resources are depleted, production will peak and then decline. As high quality, easy to find resources are depleted, production will peak and then decline.

Hubbert (1956)

Production will have a “Bell Shaped” Curve. Production will have a “Bell Shaped” Curve.

In the 1950’s, Hubbert predicted that the US oil production would peak in the 1970’s….It did. In the 1950’s, Hubbert predicted that the US oil production would peak in the 1970’s….It did. Current models predict world oil production will peak in 5-20 years Current models predict world oil production will peak in 5-20 years More when we get to each fossil fuel source. More when we get to each fossil fuel source.