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FES 86025Energy Systems Analysis

• 86025_1
• Introduction to Energy Systems

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Energy Systems

• Interaction between
• -- Society
• -- Economy
• -- Technology
• -- Policy
• that shape both
• -- Demand
• -- Supply
• in terms of quantity, quality, costs, impacts.

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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!

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Examples of Power and Energy (both kill!)
Lightning bolt Power10,000,000 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 bolts
energycould fuel a SLK for less than 1 km!
Mercedes SLK 350Power 200,000 W (200 kW,
3.5L 6-cycl) 200,000 W/s 0.2 MJ/s
Energymax 720 MJ/hr 0.2 MJ/s (x 3600
s/hr)actual Fuel use 10 l/100km 10 x 32 MJ/l
320 MJ/hr(assuming 100 km/hr)
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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.
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Energy Units and Scales(Source IPCC Energy
Primer)
Quick recap exponentials to common basis are
additive!103 x 106 10(36) 109 or 1000 MJ
1 GJ
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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)
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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

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Converting Units
conv_fac.xls v2 class server Resources/data
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Energy Flow Characteristics

• Physical chemical, kinetic, electric, radiant,
• Processing depth primary?secondary?final
• Transaction levels producer?producerproducer?co
  nsumerconsumer?consumer (future?)
• System boundariessecondary?final?useful?service

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Energy Conversions Efficiencies
conversion 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,!!
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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

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Example of Methane(ideal combustion)

• CH4 O2 ? CO2 H2O (general reaction EQ)
• Balancing for C, H, and O1 C 1 O2 ? 1 CO24 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 broken3438 kJ
  from bonds created 810 kJ net energy

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Moving beyond ideal combustionExample of CH4
Contd

• Ideal combustion810 kJ/mole Lower Heating
  Value
• Incl. energy from condensation of water
  vapor890 kJ/mole Higher Heating Value
• EmissionsCO2 only in ideal case1 mole CO2
  12gC (122x16) 44 gCO2
• Emission factors12gC/890 kJ 0.0135 gC/kJ
  13.5 gC/MJ HHV12gC/810 kJ 0.0150 gC/kJ 15.0
  kgC/GJ LHV
• S Fuel-specific energy conversion and emission
  factors that dont specify basis (LHV or
  HHV) are useless!!

mole mass in g equals molecular weight a mole
contains 6.023 1023 molecules (Avogadros number)
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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

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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 lt.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
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More info

• v2 class server
• Resources/data/doe_fueltable.pdf (useful even if
  non-metric)
• NREL (liquids) http//www.nrel.gov/vehiclesandfue
  ls/apbf/progs/search1.cgi
• Engineering Toolbox (tons of info), e.g.
• http//www.engineeringtoolbox.com/combustion-boil
  er-fuels-t_9.html

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Non-physical Definition of Energy

• System boundaries, processing depth,
  upstream/downstream primary?secondary?final ?
  ?useful?service
• Transaction levels/actors involved
  producer?producerproducer?consumerconsumer?cons
  umer (future?)

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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!)

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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/Servi
  ces
• Full Integration (IA) Whole environment (incl.
  externalities)

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Global Energy Flows (EJ in 1990)Source modified
after Nakicenovic/Gilli/Kurz, 1996. Update IEA,
2006.
2005 Total losses 340 EJ for 160 EJ useful
energy delivered