Presentation is loading. Please wait.

Presentation is loading. Please wait.

CO 2 and Energy. Context: Energy and Climate Change.

Similar presentations


Presentation on theme: "CO 2 and Energy. Context: Energy and Climate Change."— Presentation transcript:

1 CO 2 and Energy

2 Context: Energy and Climate Change

3  Consumption // Population // Energy CLIMATE CHANGE ENERGY POPULATION CONSUMPTION SOCIETAL SUCCESS NATIONAL SECURITY PUBLIC HEALTH AGRICULTURE

4 Outline Lecture 1  Lecture 1: Current and past energy use –CO 2 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 –Energy supply decarbonization ‘tools’ –Specific ‘wedges’ of mitigation

6 Key references and websites  Energy Information Administration (EIA) keeps track of (inter)national energy use and future trends.  The ‘wedge’ paper: “A plan to keep carbon in check” by Socolow and Pacala, Scientific American, –This is an influential policy-oriented paper on how to reform energy sector while still achieving economic growth –Accessible through

7 Outline Lecture 1 Revisited  Lecture 1: Current and past energy use –CO 2 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  So CO 2 emissions arise from: 1.Cement production (~5 %) 2.Deforestation (~20 %) 3.Fossil fuel use (~75 %) World Carbon Emissions 75%

9 CO 2 source: Cement Production  Cement is produced from limestone, which is mostly calcite (CaCO 3 ).  For production of cement: CaCO 3  CaO + CO 2  Production of cement emits CO 2 for two reasons: 1.CO 2 emitted directly 2.Production process takes place at high temperatures only (> 1000 ºC) which requires a lot of energy.  Accounts for ~5 % of CO 2 emissions worldwide

10 CO 2 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, CO 2 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” CO 2, since elevated CO 2 stimulates growth –Removal of forests removes this natural buffer against climate change

11 CO 2 source: Deforestation  Deforestation is thus an important part of climate change: –It accounts for ~20 % of current CO 2 emissions –It accounted for ~35 % of total CO 2 emissions since preindustrial times. Fossil fuels320 Deforestation200 Total520 Compare to 590 GtC in the preindustrial atmosphere GtC

12 CO 2 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! Energy use = (population)*(GDP/Person) *(energy/unit GDP)

15 World GDP/capita  Also strong growth in GDP/capita! Energy use = (population)*(GDP/Person) *(energy/unit GDP)

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

17 So why has energy consumption increased so much?  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 CO 2 emissions, need to drastically lower CO 2 emitted per unit energy, especially since we want economy to keep growing. –We’ll get to options for reducing CO 2 /energy in 2 nd lecture Energy use = (population)*(GDP/Person)*(energy/unit GDP)

18 Outline Lecture 1 Revisited  Lecture 1: Current and past energy use –CO 2 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 CO 2 per unit energy of all fossil fuels  Accounts for ~29% of world CO 2 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 CO 2 emissions per unit energy.  Accounts for ~30 % of world CO 2 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 CO 2 per unit energy  Accounted for ~16% of world CO 2 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 Fuel type:Proven reserves (years) Unconventional reserves (years) Oil41125 Coal Natural Gas64360 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 CO 2 emissions from plant operating, but some from uranium mining (~ % of coal emissions per unit energy)  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. EIA Annual Energy Review, 2006 Chernobyl

30 Energy sources: Renewables  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 2 nd lecture. Renewable energy as share of total energy in U.S., 2006 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: 1.It can be produced using renewable energy, which would displace fossil fuel. 2.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 –CO 2 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 Transportation sector  Sector with fastest growing CO 2 emissions in US  Dominated by oil and road transport  Accounts for ~23 % of worldwide and ~32 % of US CO 2 emissions EIA Annual Energy Review, 2006 U.S. energy consumption by sector

35 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 U.S. energy consumption by sector

36 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… EIA Annual Energy Review, 2006 U.S. industrial energy consumption by fuel U.S. energy consumption by sector

37 Agriculture  Use of direct fossil fuel energy relatively low: ~3–4.5 % in industrialized countries. –Half of used energy and direct CO 2 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 the 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 CO 2 equivalent GHG emissions (so including N 2 O and CH 4 )  Same share as entire US! –9 % of world CO 2 emissions  Fossil fuels burned to produce fertilizer  Deforestation and land use changes for feed production and grazing –37 % of world CH 4 emissions  Fermentation in cattle stomachs (biggest anthropogenic source)  Animal manure –65 % of N 2 O  Mostly from animal manure deposited on soils, with subsequent N 2 O emission

41 Outline Lecture 1 Revisited  Lecture 1: Current and past energy use –CO 2 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 Energy consumption by end use  The three main end uses of fossil fuel are: –Electric power plants (~40 % of CO 2 emissions) –Transportation (~23 % of CO 2 emissions) –Direct use of fuel (industrial processes and heating for buildings) (~37 % of CO 2 emissions)  So ~40 % CO 2 emissions from electricity, 60 % from fuels Socolow and Pacala, 2006 World CO 2 emissions by fuel and end use

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 Cost of Electricity  Coal is cheapest and most used source of electricity in US!  Solar Photovoltaic (PV) rather expensive Electricity generation by source, U.S., 2006 Cost of lectricity in US in 2002 Source: Nathan Lewis, 2009

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 Fuel type:Proven reserves (years) Unconventional reserves (years) Oil41125 Coal Natural Gas64360 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 Energy consumption by end use: Direct fuel use  ‘Direct fuel use’: –Transportation (oil) –Heating in buildings –Industrial processes  Dominated by oil  Currently no real alternatives for transportation fuels –Biofuels do not mitigate CO 2 emission (more in 2 nd lecture) Direct Fuel Use Pacala and Socolow, 2006

48 Outline Lecture 1 Revisited  Lecture 1: Current and past energy use –CO 2 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 Externality 1: Energy and National Security  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 US oil trade

50 Externality 2: 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 (NO x ), which causes respiratory problems and leads to smog –Sulfur dioxide (SO 2 ), 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

51 Externality 3: Energy and climate (besides greenhouse warming)  Burning of fossil fuels is important source of particulate matter (aerosols), which helps cool climate by: –Scattering radiation –Seeding clouds  Cleaning up ‘dirty coal’ might thus not be good for climate…

52 To be continued….  So what does our energy future look like? –Can we sustain our economic growth while avoiding ‘dangerous’ climate change? –What roles can renewable energy, hydrogen, biofuels, carbon sequestration play in this?  Will discuss in more detail in 2 nd lecture on Thursday


Download ppt "CO 2 and Energy. Context: Energy and Climate Change."

Similar presentations


Ads by Google