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SUSTAINABLE CITIESU.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 CommissionerCalifornia Energy Commission.
Distinguished Scientist EmeritusLawrence Berkeley National Lab.
[email protected] 495-2227
Presentation available at www.ArtRosenfeld.orgFile: ABA Webinar 1-11-11 from ET Summit Sac’to from Philomathia3 Berkeley and CITRIS i4E
22
Summer in the citySummer in the city
2
summer urban heat island
Chicago Heat Wave 1995, 739 Deaths
Virtually all of the deaths occurred on the top floors of buildings with black roofs
3
European Heat Wave 2003, 30,000 Deaths France July 2010, Few Deaths
4
55
Bird’s eye view of urban land useBird’s eye view of urban land use
Tree Cover 13%
Sidewalk 5%
Barren Land 8%
Misc. 6%
Road 22%
Parking Area 12%
Grass 15%
Roof 19%
Area by Land-Cover Category Above the Canopy
~ 1 km2
The surface of Sacramento, CAis about
• 20% roofs• 30% vegetation• 40% pavement
5
66
Reflective roofs stay cooler in the sun
50
40
30
20
10
0
0.0 0.2 0.4 0.6 0.8 1.0
Tem
pera
ture
Ris
e (°
C)
Galvanized Steel
IR-Refl. Black
Blac
k Pa
int
Gre
en A
spha
lt Sh
ingl
e
Red
Clay
Tile
Lt. R
ed P
aint
Lt. G
reen
Pai
nt
Wh
ite
Asp
hal
t S
hin
gle
Wh
ite
Asp
hal
t S
hin
gle
Al
Ro
of
Co
at.
Op
tica
l Wh
ite
Op
tica
l Wh
ite
Wh
ite
Pai
nt
Wh
ite
Pai
nt
Wh
ite
Cem
ent
Co
at.
Wh
ite
Cem
ent
Co
at.
Solar Absorptance
White roofs around the world
88
…in Santorini, Greece
8
99
…in Hyderabad, India
…and widelyin the state of Gujarat, India.
9
1010
Walmart store in northern California
10
1111
Congratulations to UC Davis
11
1212
White roofs are popular in Tucson, AZ
12
1313
Washington, DC (Federal) has problems
13
141414
PentagonPentagon
Cooling our planet
1616
Solar-reflective surfaces cool the globevia “negative radiative forcing”
Source: Intergovernmental Panel on Climate Change (IPCC)
16
1717
GLOBAL COOLING: making 100 m2 (1000 ft2) of gray roofing white offsets the emission of 10 t of CO2
18
How much CO2 equivalent is offset if we whiten all eligible urban flat roofs world-
wide? (i/ii)• 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.
19
How much CO2 equivalent is offset if we whitenall eligible urban flat roofs world-wide? (ii/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.
20
21
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.
22
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 Chu
calls 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
23
24
100 Cool Cities could unite many initiatives and trade associations
25
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
26
Energy Intensity (E/GDP) in the US 1949 - 2007
0
5
10
15
20
25
19
49
19
52
19
55
19
58
19
61
19
64
19
67
19
70
19
73
19
76
19
79
19
82
19
85
19
88
19
91
19
94
19
97
20
00
20
03
20
06
year
E/G
DP
= t
hou
san
d B
tu/$
(in
$2000)
Actual 1972 - 2007 Intensity drops at 2% per year
If Intensity dropped at pre-1973 levels of 0.4% per year
Actual Energy Costs: 9% of GDP in 2007 =$1.2 Trillion
15% of GDP in 2007 =$2.1 TrillionOPEC Embargo
Oil Price Collapse
2007 GDP = $14 Trillion($2007)
E/G
DP
= t
ho
us
an
d B
tu/$
(in
$2
00
0)
1970, First Earth Day
29
30
Per Capita Electricity Sales (not including self-generation)(kWh/person) (2006 to 2008 are forecast data)
0
2,000
4,000
6,000
8,000
10,000
12,000
14,0001
96
0
19
62
19
64
19
66
19
68
19
70
19
72
19
74
19
76
19
78
19
80
19
82
19
84
19
86
19
88
19
90
19
92
19
94
19
96
19
98
20
00
20
02
20
04
20
06
20
08
United States
California
Per Capita Income in Constant 2000 $1975 2005 % change
US GDP/capita 16,241 31,442 94%Cal GSP/capita 18,760 33,536 79%
2005 Differences = 5,300kWh/yr = $165/capita
31
Annual Energy Savings from Efficiency Programs and Standards
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
45,0001
97
5
19
76
19
77
19
78
19
79
19
80
19
81
19
82
19
83
19
84
19
85
19
86
19
87
19
88
19
89
19
90
19
91
19
92
19
93
19
94
19
95
19
96
19
97
19
98
19
99
20
00
20
01
20
02
20
03
GW
h/y
ear
Appliance Standards
Building Standards
Utility Efficiency Programs at a cost of
~1% of electric bill
~15% of Annual Electricity Use in California in 2003
32
Impact of Standards on Efficiency of 3 Appliances
Source: S. Nadel, ACEEE,
in ECEEE 2003 Summer Study, www.eceee.org
75%60%
25%20
30
40
50
60
70
80
90
100
110
1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006
Year
Ind
ex (
1972
= 1
00)
Effective Dates of National Standards
=
Effective Dates of State Standards
=
Refrigerators
Central A/C
Gas Furnaces
SEER = 13
33Source: David Goldstein, NRDC, SF
New United States Refrigerator Use v. Time and Retail Prices
0
200
400
600
800
1,000
1,200
1,400
1,600
1,800
2,000
1947 1952 1957 1962 1967 1972 1977 1982 1987 1992 1997 2002
Av
era
ge
En
erg
y U
se
or
Pri
ce
0
5
10
15
20
25
Re
frig
era
tor
vo
lum
e (
cu
bic
fe
et)
Energy Use per Unit(kWh/Year)
Refrigerator Size (cubic ft)
Refrigerator Price in 1983 $
$ 1,270
$ 462
34
Air Conditioning Energy Use in Single Family Homes in PG&E The effect of AC Standards (SEER) and Title 24 standards
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
1975 1980 1985 1990 1995 2000 2005 2010 2015
An
nu
al
kW
h p
er n
ew
ho
me
fo
r ce
ntr
al
AC
If only increases in house size -- no efficiency gains
Change due to SEER improvements
SEER plus Title 24
35
0
20
40
60
80
100
120
3 Gorges三峡
Refrigerators冰箱
Air Conditioners 空调
TWh
2000 Stds
2000 Stds
2005 Stds
2005 Stds
If Energy Star
If Energy Star
TW
H/Y
ear
1.5
4.5
6.0
3.0
7.5
Val
ue
(bil
lio
n $
/yea
r)
Comparison of 3 Gorges to Refrigerator and AC Efficiency Improvements
Savings calculated 10 years after standard takes effect. Calculations provided by David Fridley, LBNL
Value of TWh
3 Gorges三峡
Refrigerators 冰箱
Air Conditioners
空调
Wholesale (3 Gorges) at 3.6 c/kWh
Retail (AC + Ref) at 7.2 c/kWh
三峡电量与电冰箱、空调能效对比
标准生效后， 10年节约电量
36
United States Refrigerator Use, repeated, to compare with
Estimated Household Standby Use v. Time
0
200
400
600
800
1000
1200
1400
1600
1800
2000
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
Ave
rage
En
ergy
Use
per
Un
it S
old
(k
Wh
per
yea
r)
Refrigerator Use per Unit
1978 Cal Standard
1990 Federal Standard
1987 Cal Standard
1980 Cal Standard
1993 Federal Standard 2001 Federal
Standard
Estimated Standby Power (per house)
2007 STD.
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 2023 without regulations. The projected growth does not include the residential energy use by cable boxes, DVD players, internet boxes, Blue Ray, game consoles etc.
Televisions Represent Significant Energy Use
37
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 38
General Purpose Lighting – Proposed Regulations (cont.)
Rated Lumens Range
Maximum rated Wattage
Minimum Rated Life
Time
Proposed California
Effective Date1490-2600 Lumens 10072 Watts 1,000 hours Jan, 1, 20111050-1489Lumens 7553 Watts 1,000 hours Jan 1, 2012750-1049 Lumens 6043 Watts 1,000 hours Jan 1, 2013310-749 Lumens 4029 Watts 1,000 hours Jan 1, 2013
Proposed Table K-8: Standards for State-regulated General Services Incandescent Lamps -Tier I
Lumens Range Maximum Lamp Efficacy
Minimum Rated Life
Time
Proposed California Effective
DateAll 45 lumens per
watt1,000 hours Jan, 1, 2018
Proposed Table K-9: Standards for State-regulated General Services Lamps -Tier II
Demand Response
41
42
California is a Summer Peaking AreaCalifornia Daily Peak Loads -- 2006
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
Jan-06 Mar-06 May-06 Jul-06 Sep-06 Nov-06
MW
Residential Air Conditioning
Commercial Air Conditioning
43
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
44
Critical Peak Pricing (CPP)with Time of Use (TOU)
0
10
20
30
40
50
60
70
80
Pri
ce (
cen
ts/k
Wh
)
Standard TOUCritical Peak PriceStandard Rate
Sunday Monday Tuesday Wednesday Thursday Friday Saturday
Extraordinary Curtailment Signal, < once per year
CPP Price Signal
10x per year
?
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.
Prices are designed such that the average non-responder sees no bill change.
45
Average Residential Response to Critical Peak Pricing
kW
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Noon 2:30 7:30 Midnight
CPP Event
CPP with Controllable Thermostat
Control Group
Fixed Incentive with Controllable Thermostat
69%
65%
73%
61%
69%
22%
30%
20%
26%
17%
0% 20 40 60 80 100%
Total
TOU
CPP-F
CPP-V
Info Only
91%
93%
87%
86%
Should dynamic rates be offered to all customers?
Definitely
Probably
95%
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
46
Automated Demand ResponseCommercial Customers
*Source: Demand Response Research Center, Global Energy Partners
Smart thermostat with universal communications interface at rear Smart thermostat with universal communications interface at rear
Source: Tim Simons, Golden Power
Smart thermostat with U-SNAP InterfaceSmart thermostat with U-SNAP Interface
Advantages of this configuration:1.Customer decides2.Flexible3.“plug and play”4.Capable of conveying lots of information
Source: Tim Simons, Golden Power
