86025_4. Energy Chains and Analysis. Energy Systems Comparison Methods (models esa_13, _14, & _16) Ex: LCA Life Cycle Assessment

Transcription

1 86025_4 Energy Systems Comparison Methods (models esa_13, _14, & _16) Energy Chains and Analysis Ex: LCA Life Cycle Assessment

2 Readings: R. Righelato and D.V. Spracklen, Carbon Mitigation by Biofuels or by Saving and Restoring Forests? Science 317 (17 August):902 and Supporting Online Material Energy Chains (LCA) Linked activity patters summed and normalized per unit output Output: actual service or per energy delivered (final or useful energy output) Critical importance of system boundaries (energy usage, chain, system, economy) example light bulb: - usage: kwh electricity used - chain: J energy used in power plant (PPL) - system: J energy used for delivering energy to PPL and used in PPL - economy: system+ energy embodied in materials/services required for energy system (incl. indirect [ grey energy ] requirements)

3 Solar vs. Nuclear Electricity Chains 9 illustrative Energy Chains Delivering 6.1 TWh Electricity/year

4 Associated Materials Use Land Use of 9 Energy Chains

5 Example of Well-to-Wheel (WTW) Analysis Source: Ispra JRC, 2005 LCA Biofuels vs. Avoided Deforestation Source Righelato & Spracklen, 2007

6 Energy Chain Analysis: Example of IIASA CO2DB Broad coverage (end-use to extraction, ~2000 technologies) Comprehensiveness (technological, economic, emissions characteristics) Multiple entries (uncertainties, regional differences) No single best guess (reflecting dynamics in time, process variation, heterogeneity) Analysis (queries, energy chain analysis) The Cost of Lighting $/k-lumen-yr Fuels Conversion T&D supply systems: hcppl hard coal power plant ngcc gas combined cycle ngccr gas CC w. CO 2 recovery 2 end-use tech s ic incadescent light bulbs cl compact flourescent lb Cross-cutting End use

7 CO2 Emissions of Lighting (kg C/k-lumen-yr) 2 Cheapest and 2 nd cheapest chains Direct vs. Embodied Energy Examples HH: energy use by HH vs. energy use by agriculture and industry for producing food (and pans) consumed by HH Building: energy use by building (heating, A/C,..) vs energy used for manufacturing materials used in building s construction vs energy use associated with building use (e.g. transport energy for commuters to/from office tower)

8 Household Energy Use and Expenditure in India Buildings Life cycle CO 2 Emissions and Costs per m 2 (typical European Mediterranean conditions) Sabaté and Peters, 2008 Cheapest and most C-effective option: Thermal retrofit of buildings!

9 Energy Use in US Residential Dwellings kwh/m 2 /year Energy for heating, cooling, hot water Total energy use w/o transport US average home (2001) Passive house ~100 <15 ~250* <120 savings per typical home (150 m 2 ) per year Equivalent transport demand ~20,000 kwh 600 gal. gasoline = 15, mpg = 40 miles/day * primary energy equivalent Source: DOE Res. HH Survey 2001 Σ: moving to the suburbs in a low-energy house is hardly worth it Energy Chain & LCA Analysis + Easy comparison at investment margin + Analytical simplicity + Data sharing + Good for project-specific analysis (GEF additionality) + Imports can be considered - Representativeness of examples under proliferation of combinations (x n!) - Largely static analysis (what s the investment margin?) - Reconciliation of multiple criteria (costs, emissions) - System aspects: Diffusion potentials and constraints (capital, vintage structure, environment, relative shares of various chains)

10 Beyond Energy Chains Multiple interrelationships & circularity: Truck factory needs steel, steel factory needs iron ore, both need trucks, etc., etc. To fully account for resource use: -- Energy engineering models (for energy flows) -- Input-Output models (for intersectorial linkages, focus on industry) Possibility to extend systems boundaries Direct vs Indirect Energy Use (GJ): Life-cycle dominated by end use! Manufacturing direct per product Manufacturing indirect per product Use direct per year Use indirect per year Total over lifetime (incl. use) Example Energy used in manufacturing plant Energy used to produce raw/semi-finished materials used in manufacturing plant Energy used to operate device (gasoline, electricity) Energy needed upstream of fuel supply chain and in repair and service Car (small) Fridge Washer Newspaper (90 pages) negl (1275) 125 (120) 64 (60) 165 (0) Lifetime ~15 yrs. Typical numbers but highly variable on usage pattern typical EU values based on LCA and I-O table analysis

11 I-O: Input-Output Analysis Basically a matrix of monetary flows across sectors of an economy Info: one unit of output of sector i needs how much ($) inputs from other sectors (j..n) Based on detailed (but lagged) nationally reconciled sectorial statistics Complemented by physical flows (e.g. energy, CO 2 emissions) US- Energy per $ Value Added (TJ per Million $, energy embodiment, 1992 I-O data) Source: Carnegie Mellon Univ. Direct energy Indirect energy Product On-site Energy Transport Other Total supply sectors fertilizer passenger cars hotels semiconductors real estate agents computer&data services Note product and value orientation: Energy embodied in car vs. total energy use over lifetime of car Energy $ per VA $: industry vs. services (energy price differences)

12 I-O Tables for Energy and Environmental Analysis + Comprehensive national accounting + Widely available (mostly in OECD however) + Basically only data source for indirect energy and rucksack environmental impacts (=things happening outside the sector of consideration but linked to it) + Possibility to combine monetary with physical I-O info (resource inputs, pollutants) - Static and often delayed (5 to 10 yrs) snapshot - Average sectorial picture (difference to marginal investment, i.e. of a new plant) - Linear, proportionality assumption (2x $ car requires 2x resource inputs) - Little end-use (consumption) detail - Constrained by national border systems boundary (international trade ignored!) B-U Engineering Modeling Representation of conversion technologies linking I-O Simulation or optimization (LP) based Dynamic (back-and forecasting) LPs: Clear, simple decision rule: (discounted) cost minimization under constraints Trade explicitly considered Data rich

13 Energy Flows in MESSAGE Model B-U Engineering Models + technology detail + multi-criteria analysis + environmental constraints explicitly considered + dynamic, systems view - Extremely data intensive - Decision rule simplistic (global cost minimization) - Consumer choices poorly modeled ( rational choice assumed) - Linkage to other sectors: only captured if coupled with macro-economic models (complex)