CO 2 and Energy

1. CO2 and Energy Jasper Kok Applied Physics Program Climate science & policy enthusiast Lecture for AOSS 480, Ricky Rood

2. Context: Energy and Climate Change

3. Context: Energy and Climate Change • Consumption // Population // Energy ENERGY NATIONAL SECURITY POPULATION CLIMATE CHANGE AGRICULTURE SOCIETAL SUCCESS CONSUMPTION PUBLIC HEALTH

4. Outline Lecture 1 • Lecture 1: Current and past energy use • CO2 emissions: where do they come from? • Current sources of energy • Emissions from economic sectors • Energy consumption by end use • External costs to energy use (besides climate change)

5. Outline Lecture 2 • Lecture 2: Future energy use and climate change mitigation • ‘Business as usual’ • ‘Wedges’ to mitigate climate change from energy use • Energy efficiency • Renewable energies • Carbon sequestration • Transportation

6. Readings on local servers • Assigned Reading • Pacala and Socolow: Wedges for mitigation of climate change (Science, 2004) • Additional Relevant Reading • Pacala and Socolow: Wedges for mitigation of climate change: Supporting material (Science, 2004) • Socolow and Pacala: Keeping Carbon in Check (Scientific American, 2006) • Fundamental Information • Energy Information Administration (EIA) keeps track of (inter)national energy use and future trends.

7. Outline Lecture 1 Revisited • Lecture 1: Current and past energy use • CO2 emissions: where do they come from? • Current sources of energy • Emissions from economic sectors • Energy consumption by end use • External costs to energy use (besides climate change)

8. World Carbon Emissions • So CO2 emissions arise from: • Cement production (~5 %) • Deforestation (~20 %) • Fossil fuel use (~75 %) 75%

9. CO2 source: Cement Production • Cement is produced from limestone, which is mostly calcite (CaCO3). • For production of cement: CaCO3 CaO + CO2 • Production of cement emits CO2 for two reasons: • CO2 emitted directly • Production process takes place at high temperatures only (> 1000 ºC) which requires a lot of energy. • Accounts for ~5 % of CO2 emissions worldwide

10. CO2 source: Deforestation • Massive deforestation occurred • In developed nations during Industrial Revolution (driven by need for cheap energy) • In developing (tropical) nations right now, mostly in response to demand for cropland, pastures, and wood. • When forests are cut down, CO2 is released from: • Carbon in trees, plants, etc. (conversion to wood products preserves only small fraction) • Carbon in the soil (roots, humus) • Forests absorb “excess” CO2, since elevated CO2 stimulates growth • Removal of forests removes this natural buffer against climate change

11. CO2 source: Deforestation • Deforestation is thus an important part of climate change: • It accounts for ~20 % of current CO2 emissions • It accounted for ~35 % of total CO2 emissions since preindustrial times. GtC Compare to 590 GtC in the preindustrial atmosphere

12. CO2 source: Fossil Fuel Use • Sharp increase (16-fold!) in world energy consumption over past century • Why did this occur?

13. So why has energy consumption increased so much? • GDP/capita is considered the “societal success” • Energy use increases have been driven by growth in population and GDP/capita. Energy use = (population)*(GDP/Person) *(energy/unit GDP)

14. Energy and population • Strong population increase since pre-industrial times! http://www.j-bradford-delong.net/TCEH/1998_Draft/World_GDP/Estimating_World_GDP.html Energy use = (population)*(GDP/Person) *(energy/unit GDP)

15. World GDP/capita • Also strong growth in GDP/capita! http://www.j-bradford-delong.net/TCEH/1998_Draft/World_GDP/Estimating_World_GDP.html Energy use = (population)*(GDP/Person) *(energy/unit GDP)

16. Energy and GDP Energy use per capita and per dollar GDP in U.S. (index, 1980 = 1) • Energy/unit GDP decreases as societies become more developed  shift from manufacturing to services (root cause of Michigan’s economic woes) • But total energy use per capita does not decrease. EIA Annual Energy Outllok, 2008 Energy use = (population)*(GDP/Person) *(energy/unit GDP)

17. So why has energy consumption increased so much? Energy use = (population)*(GDP/Person)*(energy/unit GDP) • Main drivers of rapid increase in energy consumption have been increases in population and GDP/capita • This is why climate change problem is so difficult: • We can’t affect population (possible, but politically incorrect…) • Reducing GDP to combat climate change is also not feasible • But reduction in energy per unit GDP occurs with shift to knowledge-based economy (developed world now). • Still, reduction in world energy use not realistic! • To reduce CO2 emissions, need to drastically lower CO2 emitted per unit energy, especially since we want economy to keep growing. • We’ll get to options for reducing CO2/energy in 2nd lecture

18. Outline Lecture 1 Revisited • Lecture 1: Current and past energy use • CO2 emissions: where do they come from? • Current sources of energy • Emissions from economic sectors • Energy consumption by end use • External costs to energy use (besides climate change)

19. In what forms do we consume energy? • Fossil fuels: • Coal • Oil • Natural gas • Other: • Nuclear • Hydro • Renewables (mostly biomass) • ‘Hydrogen’ Pacala and Socolow, Science, 2004

20. Current sources of energy: Fossil fuels

21. Energy sources: Coal • Emits most CO2 per unit energy of all fossil fuels • Accounts for ~29% of world CO2 emissions • Used mostly for electricity and for home heating (especially in developing nations) • Coal burning emits significant amounts of sulfur, nitrogen and particulate matter • Proven reserves are almost endless (~250 years)

22. Coal is major source of air pollution • Coal emits sulfur and smoke particulates • “Great London smog” of 1952 led to thousands of casualties. • Caused by cold inversion layer  pollutants didn’t disperse + Londoners burned large amounts of coal for heating • Demonstrated impact of pollutants and played role in passage of “Clean Air Acts” in the US and Western Europe

23. Coal use in the US • After “Great London smog” of 1952, decrease in residential coal use • Use of coal for electricity has been growing consistently because coal is cheap and abundant, and combustion technology is readily available Coal use by sector in US EIA Annual Energy Review, 2006

24. Energy sources: Oil • Emits ~75 % of coal CO2 emissions per unit energy. • Accounts for ~30 % of world CO2 emissions. • Dominates transportation (cars), but also used for home/building heating • Proven reserves are ~40 years of conventional oil. After that, another ~100 years of unconventional oil (tar sands etc.) • U.S. dependency on imported oil is a major national security concern

25. Energy sources: Natural gas • Least polluting of the fossil fuels: emits ‘only’ ~60 % of coal CO2 per unit energy • Accounted for ~16% of world CO2 emissions • Used for electricity generation and home heating (same as coal) • Proven reserves are another ~65 years

26. Trend of fossil fuel use • In ‘business-as-usual’ fossil fuels will continue to dominate world energy • China currently adds one coal-fired power plant a week… International Energy Outlook, EIA, 2007

27. Reserves of fossil fuels • We won’t be running out of fossil fuels anytime soon! • ‘Unconventional’ includes oil sands, oil shale, coalbed methane, etc.. • Unconventional fossil fuels cost more energy/effort to mine Source: World Energy Assessment, 2004

28. Current sources of energy: nuclear and renewables

29. Energy sources: Nuclear • Accounts for ~6 % of world energy consumption and ~ 19 % of US electricity generation • Used only for electricity generation • No CO2 emissions from plant operating, but some from uranium mining (~10 - 20 % of coal emissions per kWh) • Concerns about nuclear waste storage and nuclear weapons proliferation • Hardly growing in most of developed world. Nuclear share of electricity generation in U.S. Nuclear power plant licenses issued in U.S. Chernobyl EIA Annual Energy Review, 2006

30. Energy sources: Renewables Renewable energy as share of total energy in U.S., 2006 • Mostly from biomass (wood), hydro power, and biofuels. • Contribution from other renewables (geothermal, solar, wind, tides) are small. • Will discuss all these in more detail in 2nd lecture. EIA Annual Energy Review, 2006

31. Energy ‘sources’: Hydrogen • Hydrogen as a fuel is often misunderstood: • Hydrogen is NOT a source of energy! • It’s merely an energy carrier, much like electricity • Hydrogen is produced by electrolyzing water:  This requires electricity • Hydrogen burns cleanly • Hydrogen’s significance is that: • It can be produced using renewable energy, which would displace fossil fuel. • Emissions are easier to mitigate, because they occur at a central location rather than individual cars. • In the absence of policies including cost of climate change, hydrogen would be generated using cheap coal-generated electricity

32. Outline Lecture 1 Revisited • Lecture 1: Current and past energy use • CO2 emissions: where do they come from? • Current sources of energy • Emissions from economic sectors • Energy consumption by end use • External costs to energy use (besides climate change)

33. Emissions from economic sectors • Industrial: creating products from raw materials (mining, cement, agriculture) • Commercial: stores, municipalities, etc. • Transportation: cars, planes, ships US energy use by sector EIA Annual Energy Review, 2006

34. U.S. energy consumption by sector Transportation sector • Sector with fastest growing CO2 emissions in US • Dominated by oil and road transport • Accounts for ~23 % of worldwide and ~32 % of US CO2 emissions EIA Annual Energy Review, 2006

35. U.S. energy consumption by sector Buildings sector • Both residential and commercial (stores, municipalities, etc.) • Mostly electricity, except for fuel use for space heating • Accounts for ~39 % of US energy use. EIA Annual Energy Review, 2006

36. U.S. energy consumption by sector Industrial sector • Includes mining, refining, factories, etc. • The fraction of energy used by this sector generally decreases as countries become more developed. • Also includes agriculture… U.S. industrial energy consumption by fuel EIA Annual Energy Review, 2006

37. Agriculture • Use of direct fossil fuel energy relatively low: ~3–4.5 % in industrialized countries. • Half of used energy and direct CO2 emissions are from fertilizer production (Haber-Bosch process) • BUT… big contributor to deforestation and land use change. • Livestock rearing is most significant contributor

38. Agriculture: Livestock • 2006 report of Food and Agriculture Organization (FAO) of the UN: • “The livestock sector emerges as one of the top two or three most significant contributors to the most serious environmental problems, at every scale from local to global.” • Important economic sector: • Employs 1.3 billion people (mostly poor) • Occupies 30 % (!) of Earth’s land surface through grazing (26 %) and feed production • 33 % of arable land for feed production

39. Agriculture: Livestock • Increasing demand for livestock products (meat, dairy) is one of main drivers of deforestation! • 70 % of deforested land in Amazon is occupied by pastures. • Feedcrops cover most of remaining 30 %. • Livestock-induced deforestation emits ~0.65 GtC per year (compared to ~7 GtC from total fossil fuel use and ~2 GtC total deforestation) • Livestock demand increasing rapidly with increasing world wealth (India, China). Should more than double by 2050.

40. Agriculture: Livestock • Responsible for ~18 % of CO2 equivalent GHG emissions (so including N2O and CH4)  Same share as entire US! • 9 % of world CO2 emissions • Fossil fuels burned to produce fertilizer • Deforestation and land use changes for feed production and grazing (bulk!) • 37 % of world CH4 emissions • Fermentation in cattle stomachs (biggest anthropogenic source) • Animal manure • 65 % of N2O • Mostly from animal manure deposited on soils, with subsequent N2O emission

41. Outline Lecture 1 Revisited • Lecture 1: Current and past energy use • CO2 emissions: where do they come from? • Current sources of energy • Emissions from economic sectors • Energy consumption by end use • External costs to energy use (besides climate change)

42. World CO2 emissions by fuel and end use Energy consumption by end use • The three main end uses of fossil fuel are: • Electric power plants (~40 % of CO2 emissions) • Transportation (~23 % of CO2 emissions) • Direct use of fuel (industrial processes and heating for buildings) (~37 % of CO2 emissions) • So ~40 % CO2 emissions from electricity, 60 % from fuels Socolow and Pacala , 2006

43. Energy consumption by end use:Electricity • Two thirds of world electricity production comes from fossil fuels • One third from hydro and nuclear power

44. Electricity generation by source, U.S., 2006 Cost of Electricity Cost of electricity in US • Coal is cheapest and most used source of electricity in US! • Solar Photovoltaic (PV) rather expensive

45. Reserves of fossil fuels (repeat) • We won’t be running out of fossil fuels anytime soon! • ‘Unconventional’ includes oil sands, oil shale, coalbed methane, etc.. • Unconventional fossil fuels cost more energy/effort to mine Source: World Energy Assessment, 2004

46. Electricity generation:Switch to renewables in future? • So in ‘business-as-usual’ abundant, cheap, fossil fuel-derived electricity will likely be available until the end of the century. • This cheap electricity can also be used to produce hydrogen fuel, should oil demand exceed supply. • Renewables will thus not play important role until • Externalities are taken into account (taxes, cap-and-trade) • There are technological breakthroughs (solar PV, fusion)

47. Direct Fuel Use Energy consumption by end use:Fuel use • ‘Fuel use:’ • Transportation (oil) • Heating in buildings • Industrial processes • Dominated by oil • No real alternatives for transportation fuels • Biofuels do not mitigate CO2 emission (more in 2nd lecture) • Future switch to renewable-powered hydrogen and/or electric cars? Pacala and Socolow, 2006

48. Outline Lecture 1 Revisited • Lecture 1: Current and past energy use • CO2 emissions: where do they come from? • Current sources of energy • Emissions from economic sectors • Energy consumption by end use • External costs to energy use (besides climate change)

49. Energy and National Security US oil trade • U.S. imports most of its oil • This is a liability, as some of that oil comes from Middle East (though not as much as one would think!) • Past (and most of current) U.S. energy policy revolves around energy security – not climate change mitigation • Majority of remaining oil in Middle East Origin of US oil imports, 2006

50. Energy and Public Health • The burning of fossil fuels is the dominant source of air pollution, emitting • Carbon monoxide (CO), which is toxic and can cause headaches and exacerbate heart disease • Nitrogen oxides (NOx), which causes respiratory problems and leads to smog • Sulfur dioxide (SO2), which produces acid rain and smog • Particulate matter, which causes respiratory problems • Mercury emissions, which are mostly taken in through fish, where they bioaccumulate. • The overall cost of air pollution on human health is large (~6 % of deaths in EU) but very difficult to quantify