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SUSTAINABLE CITIES U.S.-Australia Dialogue, 1-19-11 White Roofs to Cool your Buildings, and Cities and (this is new) Cool our Planet. Arthur H. Rosenfeld, Former Commissioner California Energy Commission. Distinguished Scientist Emeritus Lawrence Berkeley National Lab. AHRosenfeld@LBL.gov
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SUSTAINABLE CITIESU.S.-Australia Dialogue, 1-19-11White Roofs to Cool your Buildings, and Cities and(this is new) Cool our Planet Arthur H. Rosenfeld, Former Commissioner California Energy Commission. Distinguished Scientist Emeritus Lawrence Berkeley National Lab. AHRosenfeld@LBL.gov 510 495-2227 Presentation available at www.ArtRosenfeld.org File: ABA Webinar 1-11-11 from ET Summit Sac’to from Philomathia3 Berkeley and CITRIS i4E
Summer in the city summer urban heat island 2 2
Chicago Heat Wave 1995, 739 DeathsVirtually all of the deaths occurred on the top floors of buildings with black roofs
European Heat Wave 2003, 30,000 Deaths France July 2010, Few Deaths
Bird’s eye view of urban land use • The surface of Sacramento, CAis about • 20% roofs • 30% vegetation • 40% pavement ~ 1 km2 5 5
Reflective roofs stay cooler in the sun 50 40 30 20 10 0 Galvanized Steel IR-Refl. Black Black Paint White Cement Coat. Temperature Rise (°C) Green Asphalt Shingle Al Roof Coat. Red Clay Tile White Asphalt Shingle White Paint Lt. Red Paint Lt. Green Paint Optical White 0.0 0.2 0.4 0.6 0.8 1.0 Solar Absorptance 6
…in Hyderabad, India …and widelyin the state of Gujarat, India. 9 9
Pentagon 14 14
Solar-reflective surfaces cool the globevia “negative radiative forcing” Source: Intergovernmental Panel on Climate Change (IPCC) 16 16
GLOBAL COOLING: making 100 m2 (1000 ft2) of gray roofing white offsets the emission of 10 t of CO2 17
Answer: 24 Gigatonnes (Gt) 2/3 of a year’s worldwide emission Gigatonne = billion metric tons If implemented over 20 years (the life of a roof or a program) this is ≈ 1.2 Gt/year. How much CO2 equivalent is offset if we whiten all eligible urban flat roofs world-wide? (i/ii)
Offset is equivalent to taking 300 million cars off the road for 20 years. There are about 600 million passenger cars world wide, and they each emit ≈ 4 t CO2/year. How much CO2 equivalent is offset if we whitenall eligible urban flat roofs world-wide? (ii/ii)
Progress in energy efficiency standards In 2005, California’s “Title 24” energy efficiency standards prescribed white surfaces for low-sloped roofs on commercial buildings. Several hot states are following. In 2008, California prescribed “cool colored” surfaces for steep residential roofs in its 5 hottest climate zones. Other U.S. states & all countries with hot summers should follow.
Recent cool roof progress (2005 – 2011) • 2005 • California Title 24 – “Flat roofs shall be white” (15 out of 16 climate zones). Walmart adopts white roofs for ALL stores. • EPA ENERGY STAR lists Cool Roof Materials • 2010 • June 1st, 2010 – Memo from U.S. Energy Secretary Steven Chucalls for all DOE Buildings to have white roofs, if cost-effective • June 16th, 2010 – Marine Corp follows suit, Pentagon following slowly • June 19th, 2010 – RetroFIT Philly announces winner of “coolest block” contest to white-coat black roofs of row houses. • 2011 • 100 Cool Cities launched – see www.WhiteRoofsAlliance.org • Spring 2011 – US will launch, at G20 Energy Ministers meeting, a voluntary Cool Roofs initiative and may even offer technical assistance to developing countries who join early.
To come 2012… • Model codes will be modified to prescribe “flat roofs shall be white” • ASHRAE for commercial buildings • EECC for residential buildings • But states and cities have to adopt model codes
100 Cool Cities could unitemany initiatives and trade associations
Resources on the web • Art Rosenfeld’s website • ArtRosenfeld.org • Cool Colors Project • CoolColors.LBL.gov • Heat Island Group • HeatIsland.LBL.gov • Cool Communities Project • CoolCommunities.LBL.gov • Roof Savings Calculator • RoofCalc.com • White Roofs Alliance • WhiteRoofsAlliance.org • Cool Roof Rating Council • CoolRoofs.org • Cool California • CoolCalifornia.org • EPA Heat Islands • epa.gov/heatisland • Energy Star Cool Roofs • EnergyStar.gov January 2011
Energy Efficiency & Demand Response
1970, First Earth Day E/GDP = thousand Btu/$ (in $2000) ArtRosenfeld@gmail.com or PatMcAuliffe@sbcglobal.net
Impact of Standards on Efficiency of 3 Appliances 110 = Effective Dates of 100 National Standards Effective Dates of = State Standards 90 Gas Furnaces 80 75% 70 60% Index (1972 = 100) 60 Central A/C 50 SEER = 13 40 Refrigerators 30 25% 20 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 Year Source: S. Nadel, ACEEE, in ECEEE 2003 Summer Study, www.eceee.org
Comparison of 3 Gorges to Refrigerator and AC Efficiency Improvements TWh Wholesale (3 Gorges) at 3.6 c/kWh Retail (AC + Ref) at 7.2 c/kWh Value of TWh 三峡电量与电冰箱、空调能效对比 120 7.5 100 Air Conditioners 空调 If Energy Star 80 2005 Stds 6.0 Air Conditioners 空调 TWH/Year Value (billion $/year) 2000 Stds 60 4.5 If Energy Star 3.0 40 Savings calculated 10 years after standard takes effect. Calculations provided by David Fridley, LBNL 2005 Stds Refrigerators 冰箱 20 1.5 2000 Stds 0 3 Gorges 三峡 Refrigerators 冰箱 3 Gorges 三峡 标准生效后,10年节约电量
United States Refrigerator Use, repeated, to compare with Estimated Household Standby Use v. Time 2000 Estimated Standby 1800 Power (per house) 1600 1400 Refrigerator Use per 1978 Cal Standard Unit 1200 1987 Cal Standard Average Energy Use per Unit Sold (kWh per year) 1000 1980 Cal Standard 2007 STD. 800 1990 Federal 600 Standard 400 1993 Federal Standard 2001 Federal 200 Standard 0 1947 1949 1951 1953 1955 1957 1959 1961 1963 1965 1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009
Televisions Represent Significant Energy Use The residential energy consumption due to televisions rapidly increased from 3-4% in 1990s to 8-10% in 2008. Television energy will grow up to 18% by 2023without regulations. The projected growth does not include the residential energy use by cable boxes, DVD players, internet boxes, Blue Ray, game consoles etc.
Technically Feasible Standards Each point may represent several TV models *Consumers can expect to save between $ 50 - $ 250 over the life of their TV *A 50 inch plasma can consume as little as 307 kWh/yr and as much as 903 kWh/yr
General Purpose Lighting – Proposed Regulations (cont.) Proposed Table K-8: Standards for State-regulated General Services Incandescent Lamps -Tier I Proposed Table K-9: Standards for State-regulated General Services Lamps -Tier II
Three Necessary Components for Demand Response(The low-tech half of the smart grid; no Gee Whiz reliability) • Advanced Metering Infrastructure--recorded hourly • Digital meters with communication; readings available in near-real time • Dynamic Tariffs • Enable customers to be able to respond to hourly prices • The structure of these tariffs is critically important as customers are hoping to reduce total energy costs • Automated Response Technology at customer locations • Enable residential and small commercial customers to respond to price automatically • Larger customers with energy management systems linked to pricing signals over the internet or through other communication channels • And, when coupled with energy efficiency programs and policies the result can be reduction in total consumption as well as peak period consumption
Critical Peak Pricing (CPP)with Time of Use (TOU) Direct customer savings comes mainly be response to TOU. Customer response to CPP is mainly civic pride but avoids utility investment and expensive peak infrastructure. ? 80 Standard TOU 70 Critical Peak Price CPP Price Signal 10x per year Standard Rate 60 Extraordinary Curtailment Signal, < once per year 50 Price (cents/kWh) 40 30 20 10 0 Sunday Monday Tuesday Wednesday Thursday Friday Saturday Prices are designed such that the average non-responder sees no bill change.
Average Residential Response to Critical Peak Pricing Should dynamic rates be offered to all customers? CPP Event 4.5 Control Group 91% Total 69% 22% 4.0 95% 3.5 TOU 65% 30% Fixed Incentive with Controllable Thermostat 3.0 93% 73% 20% CPP-F 2.5 kW 2.0 87% CPP-V 61% 26% 1.5 86% CPP with Controllable Thermostat Info Only 17% 69% 1.0 0.5 0% 20 40 60 80 100% 0.0 Noon 2:30 7:30 Midnight Definitely Probably • Key Results from Residential Pilot • 12% average load reduction for CPP rate alone • Up to 40% with rate + enabling tech • Most participants preferred the pilot rates
Automated Demand ResponseCommercial Customers *Source: Demand Response Research Center, Global Energy Partners
Smart thermostat with universal communications interface at rear Source: Tim Simons, Golden Power
Smart thermostat with U-SNAP Interface • Advantages of this configuration: • Customer decides • Flexible • “plug and play” • Capable of conveying lots of information Source: Tim Simons, Golden Power