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Title: Are cooler surfaces a cost-effect mitigation of urban heat islands?

Abstract

Much research has gone into technologies to mitigate urban heat islands by making urban surfaces cooler by increasing their albedos. To be practical, the benefit of the technology must be greater than its cost. Here, this report provides simple methods for quantifying the maxima of some benefits that albedo increases may provide. The method used is an extension of an earlier paper that estimated the maximum possible electrical energy saving achievable in an entire city in a year by a change of albedo of its surfaces. The present report estimates the maximum amounts and monetary savings of avoided CO 2 emissions and the decreases in peak power demands. As examples, for several warm cities in California, a 0.2 increase in albedo of pavements is found to reduce CO 2 emissions by < 1 kg per m 2 per year. At the current price of CO 2 reduction in California, the monetary saving is < US$ 0.01 per year per m 2 modified. The resulting maximum peak-power reductions are estimated to be < 7% of the base power of the city. In conclusion, the magnitudes of the savings are such that decision-makers should choose carefully which urban heat island mitigation techniquesmore » are cost effective.« less

Authors:
ORCiD logo [1]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Building Technologies Office (EE-5B)
OSTI Identifier:
1377539
Grant/Contract Number:
AC02-05CH11231
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Urban Climate
Additional Journal Information:
Journal Name: Urban Climate; Journal ID: ISSN 2212-0955
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
29 ENERGY PLANNING, POLICY, AND ECONOMY; Urban heat island mitigation; Maximum electrical saving; Carbon dioxide avoided; Peak power reduction; City-wide annual; Cost effective

Citation Formats

Pomerantz, Melvin. Are cooler surfaces a cost-effect mitigation of urban heat islands?. United States: N. p., 2017. Web. doi:10.1016/j.uclim.2017.04.009.
Pomerantz, Melvin. Are cooler surfaces a cost-effect mitigation of urban heat islands?. United States. doi:10.1016/j.uclim.2017.04.009.
Pomerantz, Melvin. Thu . "Are cooler surfaces a cost-effect mitigation of urban heat islands?". United States. doi:10.1016/j.uclim.2017.04.009. https://www.osti.gov/servlets/purl/1377539.
@article{osti_1377539,
title = {Are cooler surfaces a cost-effect mitigation of urban heat islands?},
author = {Pomerantz, Melvin},
abstractNote = {Much research has gone into technologies to mitigate urban heat islands by making urban surfaces cooler by increasing their albedos. To be practical, the benefit of the technology must be greater than its cost. Here, this report provides simple methods for quantifying the maxima of some benefits that albedo increases may provide. The method used is an extension of an earlier paper that estimated the maximum possible electrical energy saving achievable in an entire city in a year by a change of albedo of its surfaces. The present report estimates the maximum amounts and monetary savings of avoided CO2 emissions and the decreases in peak power demands. As examples, for several warm cities in California, a 0.2 increase in albedo of pavements is found to reduce CO2 emissions by < 1 kg per m2 per year. At the current price of CO2 reduction in California, the monetary saving is < US$ 0.01 per year per m2 modified. The resulting maximum peak-power reductions are estimated to be < 7% of the base power of the city. In conclusion, the magnitudes of the savings are such that decision-makers should choose carefully which urban heat island mitigation techniques are cost effective.},
doi = {10.1016/j.uclim.2017.04.009},
journal = {Urban Climate},
number = ,
volume = ,
place = {United States},
year = {Thu Apr 20 00:00:00 EDT 2017},
month = {Thu Apr 20 00:00:00 EDT 2017}
}

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  • This paper presents results from energy, meteorological andphotochemical (air quality) modeling for the Los Angeles Basin, one ofthe largest and smoggiest urban regions in the U.S. and the world. Oursimulations suggest that by mitigating urban heat islands, savings of 5to 10 percent peak utility load may be possible. In addition, heat islandmitigation can reduce smog formation by 10-20 percent. in summer, whichis as effective as controlling emissions from all mobile sources in theregion. For a typical late-August episode, our simulations suggest thatimplementing cool cities in the Los Angeles Basin would have a net effectof reducing ozone concentrations. Peak concentrations atmore » 3 pm decrease byup to 7 percent (from 220 down to 205 ppb) while the total ozone mass inthe mixed layer decreases by up to 640 metric tons (a decrease of 4.7percent). Largest reductions in concentrations at 3 pm are on the orderof 50 ppb whereas the largest increases are on the order of 20 ppb. Withrespect to the National Ambient Air Quality Standard, domain widepopulation weighted exceedance exposure to ozone decreases by up to 20percent during peak afternoon hours and by up to 10 percent during thedaytime.« less
  • Data on materials and surface types that comprise a city, i.e. urban fabric, are needed in order to estimate the effects of light-colored surfaces (roofs and pavements) and urban vegetation (trees, grass, shrubs) on the meteorology and air quality of a city. We discuss the results of a semi-automatic statistical approach used to develop data on surface-type distribution and urban-fabric makeup using aerial color orthophotography, for four metropolitan areas of Chicago, IL, Houston, TX, Sacramento, CA, and Salt Lake City, UT. The digital high resolution (0.3 to 0.5-m) aerial photographs for each of these metropolitan areas covers representative urban areasmore » ranging from 30 km{sup 2} to 52 km{sup 2}. Major land-use types examined included: commercial, residential, industrial, educational, and transportation. On average, for the metropolitan areas studied, vegetation covers about 29-41% of the area, roofs 19-25%, and paved surfaces 29-39%. For the most part, trees shade streets, parking lots, grass, and sidewalks. At ground level, i.e., view from below the tree canopies, vegetation covers about 20-37% of the area, roofs 20-25%, and paved surfaces 29-36%.« less
  • Part of the urban heat island effect can be attributed to dark pavements that are commonly used on streets and parking lots. In this paper we consider two light colored, hence cooler, alternative paving materials that are in actual use in cities today. These are Portland cement concrete (PCC) pavements and chip seals. We report measurements of the albedos of some PCC and chip sealed pavements in the San Francisco Bay Area. The albedos of the PCC pavements ranged from about 0.18 to 0.35. The temperatures of some PCC pavements are also measured and calculated. We then consider how themore » albedos of the constituent materials of the PCC (stone, sand and cement) contribute to the albedos of the resulting finished concrete. The albedos of a set of chip sealed pavements in San Jose, CA, were measured and correlated with the times of their placement. It is found that the albedos decrease with age (and use) but remain higher than that of standard asphalt concrete (AC) for about five years. After t hat, the albedos of the chip seals are about 0.12, similar to aged AC. The fact that many PCC pavements have albedos at least twice as high as aged AC suggests that it is possible to have pavement albedos that remain high for many years.« less
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