Environmental Physics Chapter 1: Introduction Copyright © 2012 by DBS

Energy: A Definition Energy is the capacity to do work –You must have energy to accomplish work!

Energy: A Definition Energy is a major building block of modern society…

Energy: A Definition The standard of living refers to the quality and quantity of goods and services available to people, and the way these goods and services are distributed within a population. Highly dependent on available ENERGY resources!

Energy: A Definition Modernization from a Rural to an Urban Society… Fossil fuels made possible the rapid growth of population as transportation cost were reduced and human productivity increased greatly.

Energy: A Definition 1973 Oil embargo 1979 Iranian Revolution 2003 Iraq Invasion 1993 Gulf War Cost of gas – Energy is crucial to everyday life 9/ WW2

Energy: A Definition Energy supplies and economic growth – access to adequate and reliable energy resources is central for economic growth

Energy: A Definition Humans once had to depend on their own muscles to provide the energy to do work, today muscles supply less than 1% of the work done in the industrialized world – machines dominate

Energy: A Definition Energy might best be described in terms of what it can do. We cannot “see” energy, only its effects; we cannot make it, only use it; and we cannot destroy it, only waste it. Unlike food and housing, energy is not valued in itself but for what can be done with it. Use of energy directly affects the environment.

Energy Use and the Environment Age of environmental awareness

Increased use of fossil fuels since the industrial revolution has increased atmospheric CO 2 by 30%... Which has probably increased the earth’s temperature…

Energy Use and the Environment

Energy Use and the Environment We face very tough choices Reduce fossil fuel burning because of concern about global warming …what substitutes are there? What can take the place of gasoline in cars? Should food be used for fuel, when people are starving? Should solar energy be subsidized to compete with less expensive but more polluting fossil fuels which will run out?

Energy Use Patterns Energy consumption increased rapidly up until the 1980s… 1940s 3% more each year 1960s 5% more each year Decline in 1980s The Btu or British Thermal Unit is the energy needed to raise the temperature of 1 lb of water by 1°F

Energy Use Patterns Science, economics, and politics: shifts in the use of commercial energy resources in the United States since 1800, with projected changes to Energy consumption increased rapidly up until the 1980s… Shifts from wood to coal and then from coal to oil and natural gas have each taken about 50–75 years. Note that, since 1800, the United States has shifted from wood to coal to oil for its primary energy resource. A shift by 2100 to increased use of natural gas, biofuels, hydrogen gas produced mostly by solar cells, and wind is one of many possible scenarios. (Data from U.S. Department of Energy) Experience shows that it takes ~50 years to phase in new energy alternatives Quadrillion = 10 15

Figure 1.3: Energy consumption in the United States over the last two hundred years, by fuel used. A Btu is a unit of energy. A quadrillion Btu (or Quad) is Btu.

Energy Use Patterns Figure 1.5: World energy consumption, 1970–2025 for industrialized countries, developing countries, and Former Soviet Union. Fastest growth is in developing countries Consumption in Europe has declined slightly with the closure of energy intensive industries in former communist countries. World energy consumption is growing by about 1.9 percent a year, on average. Projected that developing countries will be using more energy than industrialized countries by 2025

p. 8 Morning rush hour, Canton, China. Fastest growth is in developing countries …tend to have very low energy consumption per person but large and rapidly growing populations, requiring significantly more energy as their living standards improve.

Figure 1.5: Regional shares of total final consumption for 2007.

Energy Use Patterns Figure 1.6: World energy consumption by country: U.S. has 5% of world population uses 1/4 of the world’s commercial energy US has one of the highest per capita rates of energy consumption of any country…

Energy Use Patterns What are the principal sources of energy in the US? Coal Oil Natural Gas Nuclear Hydropower Renewable energy

Figure 1.7: Energy consumption by source for the world and for the United States: % from fossil fuels (Non-renewable)

Oil fields in Texas in the 1920s. Where in the US was the first modern oil well drilled? Oil replaced coal as the fuel of choice

Figure 1.9: Energy consumption by source for the world and for the United States: Use of natural gas has increased to ~ 23% Large decrease in contribution from wood and coal Rapid rise of oil and gas since WW2

Figure 1.10: United States petroleum production and imports: 1949–2003. (Petroleum includes crude oil and natural gas plant liquids.) Until 1940s US produced virtually all the oil it needed Petroleum imports begin Current production Current imports

Fundamental Sources of Energy FUSION (SOLAR) FISSIONGRAVITATIONAL (PE/KE earth- moon-sun) Fossil fuels Wind Waves Biomass Hydro Direct solar Nuclear energy (man-made) Geothermal (natural) Tides

Energy Use Patterns Renewable energy sources –solar –wind –waves –hydro –biomass –geothermal –tidal Wind energy is the world’s fastest growing energy source, 25 % per year

p. 12 The 350-kW photovoltaic power plant at Gun Hill Bus Depot in New York City. Solar cells supplement the terminal’s electrical energy needs.

Energy Use Patterns Energy is not an end to itself but is valued for what can be done with it End uses of energy: Figure 1.12: United States end uses of energy by sector: 2009.

Figure 1.13: United States total energy flow in 2003 (Quadrillions of Btu). Total energy consumed—98.2 Quads—includes conversion and transmission losses of electric utilities. (NGPL = Natural Gas Plant Liquids)

Energy Resources Estimates for coal are easiest to make…why? To understand energy one must understand energy resources, their limitations and their uses Reserves are not static…why? bbl = barrels, Btu = British Thermal Unit, cf = cubic foot 2 important factors: i) Size ii) Lifetime

Residence Time Average amount of time a particle exists before it is removed. Can be used to measure remaining reserves. Defined as follows: Residence time = amount of substance in the system rate of flow from the system e.g. example 1.1: US oil reserves are est. at 29 x10 9 bbl (from previous table), current production is 6 MBPD. How many years will it last? Note: this is a simplification as both of these numbers change.

The Washington Post, 03/20/08

Energy Use in China Figure 1.15: Energy resources used in China: Per capita consumption is far less than USA 33 Mbtu vs 333 Mbtu GDP growing at 10 % per year World’s largest consumer of coal Eenergy usey may eventually surpass US

Exponential Growth and Resource Depletion To specify the lifetime of a resource you must also specify the expected rate of growth in its use Exponential growth is growth by the same percentage rate each year The larger a quantity gets, the faster it grows Consider $1000 growing at 10% per year By the 7 th year the investment has doubled By the 14 th year the investment has doubled again If we plot this graph what does it look like?

Exponential Growth and Resource Depletion A useful relationship between doubling time and percentage growth is: Doubling time ~ 70 years % growth rate To specify the lifetime of a resource we must also specify the expected rate of growth in its use Growth rate of 7% for electrical energy, amount consumed would double in about 70/7 = 10 years If we want to find out exactly how much of a resource is present we need to solve a different equation At 0% growth coal will last 500 years, with a 5% growth rate in the consumption of coal per year its lifetime would be less than n years, find n: US coal reserves = 7 x Btu (table 1.1) 2003 consumption = 23 x Btu per year (Appendix F) 23 x x (1.05) n = 7 x n = 117

Resource Depletion However: Use of a resource will not continue to grow exponentially indefinitely Figure 1.18: World coal production cycle. The probable exploitation of a fossil fuel (coal in this case) can be characterized by the solid curve. Production initially increases exponentially (as shown by the dashed line), but its rate of increase eventually decreases. Production then declines as extraction becomes more difficult and the rate of discovery decreases. Knowing the amount of fuel initially present, we can use this pattern to determine the lifetime of a resource; in this example, the lifetime of coal reserves is 400 to 600 years. (The amount of coal used so far is shown by the shaded area.) Hubberts bell-shaped curve

Figure 1.19: United States oil production. Comparison of estimated (Hubbert) production curve (dashed line) and actual production (solid line). Oil – estimated vs. actual Resource Depletion

Figure 1.20: United States natural gas production. Comparison of estimated (Hubbert) production curve (dashed line) and actual production (solid line). Natural Gas – estimated vs. actual

Exponential Growth and Resource Depletion Use of a resource will not continue to grow indefinitely Hubbert curves allow estimate of time of depletion and maximum use (Hubbert’s Peak) Implies coal will last > 500 years Implies oil will last ~ 50 years Implies gas life extended by advances in production technologies e.g. fracking

Oil: A Critical Resource Oil has fueled most of the increase in global energy consumption since WW Oil embargo 1979 Iranian Revolution 2003 Iraq Invasion 1993 Gulf War 9/11 We import 56 % of the oil we use Use is growing at 1.5 % per year Decline in prices encouraged increase in use

p. 22 A map of the Middle East. d

Energy Conservation Total energy consumed in an activity = efficiency of the activity + frequency of activity e.g. energy consumed by a car depends on mpg and no. miles driven Energy conservation focuses on these two factors: 1. Technical fix – more fuel efficiency, CFL’s 2. Lifestyle changes – driving fewer miles, turning lights off

Energy Conservation

Many people assert that energy prices should reflect what it will cost to replace the dwindling supplies of nonrenewable fuels, rather than just what it cots to obtain them Societies will not switch to RES and higher efficiency if fossil fuels are prices as if they are almost free Higher oil prices in 1980’s led to lower per capita energy use Between 1900 and 1980 per capita energy use rose from 80 Mbtu to 320 Mbtu Are we 4 x better off? Figure 1.23: United States per capita energy consumption over the past 130 years.

Energy Conservation 1. Conservation technologies are cost-effective alternatives to the development of additional supply technologies. 2.Conservation will stretch the earth’s limited energy resources and gain time for the development of RES. 3. Conservation will reduce pollution of our environment. 4. Conservation technologies can be put to use more quickly than we can increase supplies. It takes several years to build new power plants whilst it takes a few days to insulate a home. 5. Conservation of fossil fuels is crucial for their use as raw materials in the pharmaceutical and plastic industries. 6. Conservation can be readily practiced by individuals and promotes good health, e.g. bicycle riding.

Economic and Environmental Considerations Commonly held belief that GDP only increased when using lots of energy Higher oil prices of the 1980s tested this theory Higher oil prices lead to increased conservation measures Energy use fell whilst GDP continued to rise Trend of conservation continues as can be seen by decrease in ‘energy intensity’ (Btu/GDP ratio) Figure 1.16 (prev. ed.): United States energy use (Btu) compared to GDP over time, and their ratio.

Figure 1-24 p27

Economic and Environmental Considerations Energy policy should not only be concerned with finding new sources and reducing consumption What do we give up, and for what? –Do we sacrifice ANWR in return for 10 more years of oil? –Was the 1989 Exxon Valdez Alaskan oil spill acceptable? –Is climate change a threat? –Is acid rain an issue? –Is nuclear power safe?

Figure 1-25 p28

Future Scenarios The global energy and political situation today is dramatically different from that in the early 1970s. Lower oil prices in the 1990s brought increased oil consumption and discouraged energy conservation and the development of alternative energy resources. However, the economic environment has changed in a way that may make it easier to handle future supply disruptions or shortages 1. US depends less today on oil than we did ten years ago. 2. Oil production is more dispersed amongst world nations than in Due to the volatility of oil prices in the last 30 years we have learnt to conserve fuel and use more efficient machines. 4. Strategic petroleum reserve. 5. RES are undergoing rapid growth.

Chapter 1 Questions 2. What energy source has seen the most rapid growth in the past 50 yrs? Why? 3. If world use of oil is 78 MBPD, how long will it last?(hint: use example 1.1) 5. If the world’s population is increasing at 1.3 % per year and there were 5 billion poeple in 1986, in what year will there be 10 billion? 15. Should environmental impacts always be given first concern when it comes to the use of energy? 24. Find the present numbers for US consumption of energy. Cite your URLs.