Protecting the Box Creating and Conserving Energy for Big Box Buildings and Stadiums with Roofs By...

Information and map from MrSolar.com

Protecting the Box

Creating and Conserving Energy for

Big Box Buildings

and Stadiums with Roofs

By Rey Arnaldo Phillips [email protected]

Spring 2004

Energy Law

Professor Bosselman

Chicago-Kent College of Law


Goals

• Develop techniques of profitable sustainability

• Reduce demand for baseload power plants by– Increasing amount of power produced during

peak demand– Reducing the demand for power

Photo from www.generalgrowthproperties.com/malls/photoinfo.asp?smuid=670#

Audience

• Malls• Big box stores

– Wal-Mart

– Target

– Circuit City

– Best Buy

– Etc.

• Stadiums

Why Stadiums?

• High-Profile• Easy way to

communicate to people of all ages

• Innovative Designs• Good publicity for the

teams


Big Box Stores

• Many of these same ideas can be applied to big box stores.

• Target is already famous for giving to schools. This would be another connection to schools and community.

• A stadium naming tie-in with a solar panel push on all stores would be big, positive publicity, plus economically and environmentally friendly


Typical Big Box Stores

# of stores Smallest Largest

Wal-Mart 3,559 42,000 220,000

Target 1,107 125,000 175,000

Best Buy 750 20,000 45,000

Circuit City 599 15,000 45,000


Fun with EstimatesPossible Square Footage of Flat Roofs in USA

Wal-Mart 533,850,000

Target 166,050,000

Best Buy 22,500,000

Circuit City 17,970,000

Subtotal 740,370,000

Malls 280,000,000

Total 1,020,370,000


Conventional Flat Roofs

• Subject to large swings in temperatures that cause cracking and leaking

• Temperatures can reach 176 degrees Fahrenheit

• Last between 5 and 20 years before replacement

• Avg cost per square foot is $55 to $85


Urban Heat Island Effect

• The predominance of dark surfaces in urban areas—from roofs, streets, parking lots—results in higher temperatures by as much as 6 to 10 degrees Fahrenheit.

• About 60% of roofs in Chicago are dark colored.


Three Roof Types

• Solar Roofs

• Green Roofs

• Reflective Roofs

Photo from http://iseanetwork.org/tour/chicago/

Solar Roofs


CE7160 CE10160 CE14160 CE20160 CE30160 CE40160 CE50160 CE60160 CE70160

147.1 210.1 294.2 420.3 630.4 840.6 1050.7 1260.9 1471119.8 171.2 239.6 342.3 513.5 684.7 855.9 1026.9 1198.1115.1 164.4 230.1 328.8 493.2 657.6 822 986.4 1150.8105.6 150.8 211.2 301.7 452.5 603.3 754.1 905.1 1055.998.5 140.7 196.9 281.3 422 562.7 703.4 843.9 984.6

98 140 196 280 420 560 700 840 980Approximate Roof Area Required (Square Feet)

This information is approximated for a south facing array with no shade at a 30 degree tilt angle.

Typically Average Monthly Output (AC kWH)

From www.spiresolarchicago.com/solar/PVbasics.html


Advantages

• Clean power

• Free energy

• Helps shade roofs

• Modular

• Existent roof friendly

• Long-lasting

• May be used for emissions trading

Advantages

• Gives power when it is needed most– During peak periods

• Daytime• Summer

– Result: Reduces number of baseload plants

• Helps achieve Illinois renewable energy goal

• Reduces risk of price volatility


Disadvantage

• Cost– According to one estimate, cost is 11 cents per

kWh– According to another, the system pays itself off

in 6 years– Little agreement in industry


Illinois Department of Commerce and Economic Opportunity (DCEO) • Division of Energy Conservation and

Alternative Energy – Promotes Energy Efficiency

• Education• Identification of means of financing

• Bureau of Energy and Recycling – Alternative Energy Development Section

• Renewable Energy Resources Program • 20 ILCS 687 Article 6


Illinois Department of Commerce and Community Affairs (DCCA)

• Rebate Program– $6/watt up to $5000– There used to be other programs, including

grants up to $300,000, but those have been scrapped.


Chicago Photovoltaic Incentive Program(a.k.a. ComEd Solar Electric Incentive Program)

• In 2004, grants rebates of $1000 per kW, for systems between 1 and 50 kW

• Must be eligible under the Renewable Energy Resources Program

• Must purchase from Spire Solar Chicago

• Must be in Chicago

• Must have a ComEd account


Mainstay Energy Rewards Program

• Private company which buys Renewable Energy Credits from small to medium sized producers of renewable energy.

• They pay 2 to 5 cents per kWh• They then sell these credits • Efficient because they can gather volume

and specialize while saving businesses money

www.mainstayenergy.com

Green Tag


Fun with EstimatesPossible Square Footage of Flat Roofs in USA

Wal-Mart 533,850,000

Target 166,050,000

Best Buy 22,500,000

Circuit City 17,970,000

Subtotal 740,370,000

Malls 280,000,000

Total 1,020,370,000


• A 50 kW unit needs about 5000 to 5500 square feet of roof space.

• In Chicago, at a 0 degree angle, it should produce about 51,700 kWh per year.

• Applied to the billion square feet of estimated roof space, more than 185,000 units could be installed.

• Result:

9,564,500 MWh/year


Savings and Costs

• This would save about 7.6 million tons per year of carbon dioxide being released.

• But the cost would not be small. At current prices it could come to as much as $93 billion dollars.

• Over 30 years, the cost per kWh comes to about 3.22 cents/kWh.

(L) www.greenroofs.org (R) www.roofmeadow.com

Green Roofs

Chicago’s City Hall

Photo from www.greenroofplants.com

Extensive Green Roofs

• 2-4 inches of soil• 12 to 40 pounds/sq. ft.

of roof area• Short, drought

resistant plants with shallow root systems like sedum and hard fescue

http://www.greenroofplants.com/plugs.JPG

Photo from www.hydrotechusa.com

Extensive Green Roof System

Photo from http://wisplants.uwsp.edu

Yellow Sedum

Photo from http://wisplants.uwsp.edu

Hard Fescue


Intensive Green Roof


Intensive Green Roof System

• 6-12 inches of soil

• 80 to 150 pounds/sq. ft. of roof area

• Able to host deeper-rooted plants, e.g. shrubs and trees

• More maintenance needs, e.g. irrigation and pruning


Advantages

• Conserves energy by moderating temperatures within buildings

• Extends roof life• Reduces noise• Aesthetics

• Absorbs rainfall• Reduces runoff• Filters rainfall• Plants filter air• Combats Urban Heat

Island Effect


Disadvantages

• Not possible for all roofs based on architectural need

• Some maintenance necessary

• Design and cost is about 50% more expensive than a conventional roof, though this is recouped by the fact that the roof lasts twice as long.


Penn State test

Ambient Air 88° F

Plastic-Sheet Roof 140° F

Gravel roof 118° F

Green Roof 82° F

www.ornl.gov/sci/roofs+walls/research/reflective.htm

Reflective Roofs


Reflective Roof System

• Can reduce roof surface temperatures by 60 degrees Fahrenheit

• Most basic technique – paint the roof with a reflective paint

• Many suppliers of coatings and coverings

• Some materials may be recycled, e.g. Thermoplastic Polyolefin


Advantages

• Relatively inexpensive—many cost the same as dark-colored roofing materials

• Moderates temperatures

• Extends roof life

• Reduces Urban Heat Island Effect by reducing the total area of dark, heat-absorbing surfaces


Disadvantages

• Short life– Reflectance reduces over time because of dirt

and weather damage


Roofed Stadiums

• Glasgow Ibrox, Scotland

• Seats 57,000 • Renovated in 1997• Light colored roof

reflects the heat• Roof over all of the

stands protects fans from the elements

Kingston Communications Stadium, England, seating about 26,000

Roofed Stadiums

• Kingston Communications Stadium, England

• Seats 25,500• Light colored roof

reflects the heat• Angle can be directed

toward the sun for solar panels


Roofed Stadiums


Conclusions

• Solar– Most expensive up front cost– Incentives would help defray– Competitive over long term– Reduces risk to price volatility – Very clean– More research might improve efficiency of

panels


Conclusions

• Green roofs– Should be incentives– Failing incentives, energy efficiency

requirements in the building code which would encourage green roofs

– More research is needed for percentage of savings

– Greatest aid to Urban Heat Island Effect reduction


Conclusions

• Reflective roofs– Are so inexpensive that they simply make good

business sense.– No incentives should be needed, but like with

the green roofs, energy efficiency requirements could encourage them.

Protecting the Box Creating and Conserving Energy for Big Box Buildings and Stadiums with Roofs By...

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