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F&ES 86025 Energy Systems Analysis

F&ES 86025 Energy Systems Analysis. 86025_1 Introduction to Energy Systems. Energy Systems. Interaction between: -- Society -- Economy -- Technology -- Policy that shape both -- Demand -- Supply in terms of quantity, quality, costs, impacts. Definitions & IS Units.

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F&ES 86025 Energy Systems Analysis

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  1. F&ES 86025Energy Systems Analysis 86025_1 Introduction to Energy Systems Arnulf Grubler

  2. Energy Systems Interaction between: -- Society -- Economy -- Technology -- Policy that shape both -- Demand -- Supply in terms of quantity, quality, costs, impacts. Arnulf Grubler

  3. 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! Arnulf Grubler

  4. Examples of Power and Energy (both kill!) Lightning bolt Power:10,000,000 kW(1 109 Voltx 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! Mercedes SLK 350Power: 200,000 W (200 kW, 3.5L 6-cycl) = 200,000 W/s = 0.2 MJ/s Energy:max: 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)

  5. Power Examples Source: updated and modified after Tester et al., 2005.

  6. 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 Arnulf Grubler

  7. 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) Arnulf Grubler

  8. 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 Arnulf Grubler

  9. Converting Units conv_fac.xls v2 class server “Resources/data” Arnulf Grubler

  10. 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 Arnulf Grubler

  11. Energy Conversions & Efficiencies Adapted from Smil, 1998.c = chemical, e = electrical, m = mechanical, r = radiant, t = thermal Efficiency depends on form adequacy, technology, scale,…!!

  12. 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 Arnulf Grubler

  13. Example of Methane(ideal combustion) • CH4 + O2→ CO2 + H2O (general reaction EQ) • Balancing for C, H, and O:1 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 broken+3438 kJ from bonds created+ 810 kJ net energy Arnulf Grubler

  14. 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)

  15. 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 Arnulf Grubler

  16. Characteristics of Some FuelsSource: D. Castorph et al., 1999, GRI, 2005. * Note difference to LHV on volume basis: gas: 40 MJ/m3 H2: 10.8 MJ/m3

  17. 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 Arnulf Grubler

  18. 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?) Arnulf Grubler

  19. 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!) Arnulf Grubler

  20. 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”) Arnulf Grubler

  21. Global Energy Flows (EJ in 1990)Source: modified after Nakicenovic/Gilli/Kurz, 1996. Update: IEA, 2006. In 2005:(#’s rounded) Hydro- Nuclear- power power Crude oil Coal Natural gas Renewables** TPC: 380.8 TPC: 380.8 133.2 91.1 70.6 20.5 18.8 46.6 Primary:500 EJ Oil: 133.2 Coal: 91.1 ALS* ALS* Gas: 70.5 0.1 8.0 Renewables: 20.5 International Hydro: 18.8 bunkers Nuclear: 46.6 5.0 ALS* 9.3 ** Includes traditional fuels losses:-180 EJ 50.3 14.3 20.5 20.4 18.8 2.0 Conversion losses 74.7 Conversion loss ALS* ALS: 110.8 1.3 ALS* Central electricity & heat generation 51.5 4.7 7.6 Trans- mission loss Final: 320 EJ 17.8 14.1 0.1 1.2 59.1 0.8 0.3 0.8 1.6 25.5 21.6 20.1 2.6 9.8 17.7 21.8 41.9 TFC: 270.0 TFC: 270.0 Oil: 106.0 60.9 108.9 84.9 Renewables: 44.5 losses:- 160 EJ Gas: Loss 40.8 Loss Loss 29.9 Coal: 36.1 42.6 60.0 Electricity: 34.8 Useful energy: Heat: 7.8 137.5 15.4 18.3 55.0 48.9 Residential & commercial Feedstocks Transportation Industry Useful:160 EJ *ALS = Autoconsumption, losses, stock changes 2005: Total losses: 340 EJ for 160 EJ useful energy delivered Arnulf Grubler

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