86025 Energy Systems AnalysisArnulf Grubler F&ES 86025 Energy Systems Analysis 86025_1 Introduction...
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Transcript of 86025 Energy Systems AnalysisArnulf Grubler F&ES 86025 Energy Systems Analysis 86025_1 Introduction...
86025 Energy Systems Analysis Arnulf Grubler
F&ES 86025Energy Systems Analysis
86025_1
Introduction to Energy Systems
86025 Energy Systems Analysis Arnulf Grubler
Energy Systems
Interaction between:-- Society-- Economy-- Technology-- Policythat shape both-- Demand-- Supplyin terms of quantity, quality, costs, impacts.
86025 Energy Systems Analysis Arnulf Grubler
Definitions & IS Units• Energy: Capacity to do work• Power: Rate of energy transfer
• Newton (N): 1 kg m/s (force)• Joule (J): 1 N applied over 1 m (energy)• Watt (W): 1 J/second (power)
• Example: 1 HP = 745 W (745 J/s) for 1 hr = 0.745 kWh
Energy = Power x Time Hence importance of load factors and load curves!
Examples of Power and Energy (both kill!)
Mercedes SLK 350Power: 200,000 W (200 kW, 3.5L 6-cycl)= 200,000 W/s = 0.2 MJ/s
Energy:max: 720 MJ/hr0.2 MJ/s (x 3600 s/hr)actual:Fuel use: 10 l/100km= 10 x 32 MJ/l = 320 MJ/hr(assuming 100 km/hr)
Lightning boltPower:10,000,000 kW(1 109 Volt x 1 104 Ampere)for 1 second = 10,000 MJ/s
Energy:max. equiv.: 2.8 MJ/hr
Fazit: Even if storable/useablea lightning bolt’s energycould fuel a SLK for less than 1 km!
Power Examples
Human heart ~1 W
Light bulb 100 W
Horse 1000 W = 1 kW (kilo Watt)
Car 100,000 W = 100 kW
Yale PPL 20,000,000 W = 20 MW (Mega Watt)
Boeing 747at max thrust
250,000,000 W 250 MW =
.25 GW
Niagara Falls 2,000,000,000 W 2 GW (Giga Watt)
All US PPL 885,000,000,000 W 885 GW
All World PPL 3,500,000,000,000 W 3500 GW
All US Automobiles 230 million with ~ 100 kW each
23,000 GW
Source: updated and modified after Tester et al., 2005.
86025 Energy Systems Analysis Arnulf Grubler
Energy Units and Scales(Source: IPCC Energy Primer)
zettajoule (ZJ)
Quick recap: exponentials to common basis are additive!103 x 106 = 10(3+6) = 109 or 1000 MJ = 1 GJ
86025 Energy Systems Analysis Arnulf Grubler
Energy Orders of Magnitude (EJ = 1018 J)
5,500,000 EJ Annual solar influx 1,000,000 EJ Fossil occurrences 50,000 EJ Fossil reserves 440 EJ World energy use 2000
100 EJ USA primary energy supply 50 EJ OECD transport energy use
20 EJ Saudi Arabia oil prod. 4 EJ Italy oil reserves 1 EJ NY city or Singapore
energy use
Stocks; flows (yr-1)
86025 Energy Systems Analysis Arnulf Grubler
Rough Equivalences
10 Gtoe = 420 EJ 1 Gtoe = 42 EJ 1 Quad = 1 EJ 1 Mtoe = 42 PJ 1 toe = 42 GJ 1 boe = 6 GJ 1 m3 gas = 40 MJ 1 kWh = 4 MJ 1 Btu = 1 kJ
86025 Energy Systems Analysis Arnulf Grubler
Converting Units
conv_fac.xls
v2 class server“Resources/data”
86025 Energy Systems Analysis Arnulf Grubler
Energy Flow Characteristics
• Physical: chemical, kinetic, electric, radiant,…
• Processing depth: primary→secondary→final
• Transaction levels: producer→producerproducer→consumerconsumer→consumer (future?)
• System boundaries:secondary→final→useful→service
Energy Conversions & Efficienciesconversion 1st Law efficiency
Electric generator m → e ~99%
Gas furnace c → t 90-95%
Small electric drive e → m 60-65%
Steam turbine t → m 40-45%
Best PV cells r → e 20-30%
Trad. Cook stove c → t 10-15%
Beef production c → c 5-10%
Fluorescent light e → r ~10%
Incandescent light e → r 2-5%
Paraffin candle c → r 1-2%
Global photosynthesis
r → c 0.3%
Adapted from Smil, 1998.c = chemical, e = electrical, m = mechanical, r = radiant, t = thermal
Efficiency depends on form adequacy, technology, scale,…!!
86025 Energy Systems Analysis Arnulf Grubler
Conversions are far from trivial: Example of combustion (c → t)
• Fuel + oxidizer = Products ± energy• In ideal conditions: energy is the net sum of
creation/destruction of chemical bonds-- exothermic: producing energy(e.g. CH4 as fuel)-- endothermic: needing energy(e.g. CH4 as chemical feedstock)
• But combustion is generally far away from ideal leading to accounting complexities (HHV, LHV) and most important of all: emissions beyond ideal combustion conditions
86025 Energy Systems Analysis Arnulf Grubler
Example of Methane(ideal combustion)
• CH4 + O2 → CO2 + H2O (general reaction EQ)
• Balancing for C, H, and O:1 C + 1 O2 → 1 CO2
4 H + 1 O2 → 2 H2Ono oxygen in this fuel (but e.g. in wood!)
• Therefore: CH4 + 2O2 → CO2 + 2H2O
• Net energy: - 2628 kJ from bonds broken+3438 kJ from bonds created+ 810 kJ net energy
Moving beyond ideal combustion:Example of CH4 Cont’d
• Ideal combustion:810 kJ/mole = Lower Heating Value
• Incl. energy from condensation of water vapor:890 kJ/mole = Higher Heating Value
• Emissions:CO2 only in ideal case1 mole* CO2 = 12gC = (12+[2x16]) = 44 gCO2
• Emission factors:12gC/890 kJ = 0.0135 gC/kJ = 13.5 gC/MJ HHV12gC/810 kJ = 0.0150 gC/kJ = 15.0 kgC/GJ LHV
Σ : Fuel-specific energy conversion and emission factors that don’t specify basis (LHV or HHV) are useless!!*mole: mass in g equals molecular weight a mole contains 6.023 1023 molecules (Avogadro’s number)
86025 Energy Systems Analysis Arnulf Grubler
The Real World
• Emissions under real conditions:-- combustion in air and not pure oxygen →N emissions (air: 21% O, 78% N, 1% other)-- fuel impurities (S, N, ash, heavy metals..) -- incomplete combustion (e.g. hydrocarbons, CO, soot, etc…)
• Important tradeoffs: higher efficiency → higher combustion temperature (cf. second law of thermodynamics) → higher N emissions
• Scale dependency (emissions, and control possibilities): preference for large, centralized combustion
Characteristics of Some FuelsSource: D. Castorph et al., 1999, GRI, 2005.
C%
H%
S%
O%
N%
Ash%
H2O%
LHVkJ/g
HHVkJ/g
HHV/LHV
Wood 50 6 0 44 0 <.5 10-20
14.6-16.8
15.9-18.0
1.07-
1.09
Coal(hard coal)
88 5 1 4.5 1.5 3-12 0-10 27.3-24.1
29.3-35.2
1.05-1.07
Diesel 86 13 .3 - - - - 43.0 45.9 1.07
Natural Gas*(Range)
CH4
74-98
CHs
0-20
H2S
0-5
CO2,O2
0-8
N2
0-5
- -
38-48 42-56 1.10-
1.17
H2* 100 - - 120 142 1.18
* Note difference to LHV on volume basis: gas: 40 MJ/m3 H2: 10.8 MJ/m3
86025 Energy Systems Analysis Arnulf Grubler
More info:
v2 class server: Resources/data/doe_fueltable.pdf (useful even if non-metric)
NREL (liquids): http://www.nrel.gov/vehiclesandfuels/apbf/progs/search1.cgi
Engineering Toolbox (tons of info), e.g.:http://www.engineeringtoolbox.com/combustion-boiler-fuels-t_9.html
86025 Energy Systems Analysis Arnulf Grubler
Non-physical Definition of Energy
• System boundaries, processing depth, upstream/downstream: primary→secondary→final → →useful→service
• Transaction levels/actors involved: producer→producerproducer→consumerconsumer→consumer (future?)
86025 Energy Systems Analysis Arnulf Grubler
What means….
• Primary energy: Resources as extracted from nature (crude oil, solar heat)
• Secondary energy: Processed/converted energy (gasoline from crude oil, electricity from coal or hydropower)
• Final energy (as delivered to consumer)• Useful energy (converted by final appliances
(heat from radiator, light from bulb)• Services = actual demand: comfort,
illumination, mobility,… (units ephemeral!)
86025 Energy Systems Analysis Arnulf Grubler
System Boundaries
• Energy sector: Primary→ Final (domain of supply bias)
• Energy end-use: Final→Useful (domain of consumer bias)
• Energy Integration (IRM, LC): Primary→Useful/Services
• Full Integration (IA): Whole environment (incl. “externalities”)
86025 Energy Systems Analysis Arnulf Grubler
14.3 50.3 20.5 20.4 18.82.0Conversion loss 74.7
Crude oil133.2
Coal91.1
Natural gas70.6
Hydro-power
20.5
Nuclear-power
18.8Renewables**
46.6
ALS*9.3
ALS*4.7
Transportation Industry Residential & commercial
** I
nclu
des
trad
ition
al f
uels
TPC: 380.8
TFC: 270.0
ALS*8.0
Feedstocks
15.4
Internationalbunkers
5.0
Useful energy:137.5
*ALS = Autoconsumption, losses, stock changes
TPC: 380.8
7.6Trans-missionloss
TFC: 270.0
84.9
29.9Loss
60.0
108.9
Loss
60.9
42.6Loss
55.018.3
Central electricity & heat generation
48.9
ALS*1.3
ALS*0.1
14.10.1 1.2
Conversionlosses
ALS: 110.851.5
Oil:Coal:Gas:
Renewables:Hydro:
Nuclear:
133.291.170.520.518.846.6
106.044.540.836.134.87.8
Oil:Renewables:
Gas:Coal:
Electricity:Heat:
59.1 0.30.8 0.8 1.6 25.5 21.6 20.1 2.6 9.8 17.7 21.8 41.917.8
Global Energy Flows (EJ in 1990)Source: modified after Nakicenovic/Gilli/Kurz, 1996. Update: IEA, 2006.
In 2005:(#’s rounded)
Primary:500 EJ
Final:320 EJ
Useful:160 EJ
losses:-180 EJ
losses:- 160 EJ
2005: Total losses: 340 EJ for 160 EJ useful energy delivered