Roofs as Economic Generators
Scorecard Categories Addressed
- Unemployment Rate
- Median Household Income
- Live and Work in the City
- Cost of Living
Roofs are a missed opportunity for economic growth of the community.
Some potential economic generators for rooftops include:
- PV Solar Panels
- Green Roof
- Edible Green Roof
The PV solar panels would, somewhat obviously, generate electricity that
the building owner can use to reduce their electric bill. In the extreme
case, there will be a surplus of electricity that the building owner
can sell back to the local utility company and actually make money
instead of just saving money.
Green roofs can significantly reduce the building's heating and cooling needs.
Green roofs can also reduce urban heat islands, thereby making the
city more people friendly.
Extending the heating and cooling benefits of green roofs to edible green
roofs would have the additional benefit of increasing local jobs as well as local food.
If enough rooftops install solar, and the region is getting close to exceeding
current electric plant capability, these rooftop electric generators could
prevent the region from having to invest in a new power plant, thus saving
everyone an electric rate increase to pay for the new plant.
Families with Kids
More job opportunties. Access to local, healthy food. Cleaner air.
Access to local, healthy food. Cleaner air.
Applying these ideas to city buildings can free up money
for other projects.
Developers and Building Owners
Another source of income. Roofs no longer just an expense.
- Stormwater management, dramatically reducing and slowing
the speed of water runoff plus helping to clean the water
before leaving the site.
- Extend the life cycle of the roof membrane by protecting it
from the harsh elements and puncture from people
doing roof maintenance.
PV Solar Panels:
state of Colorado
recently passed a law making it much easier for
non-utility companies to resell electricity. For example, the building
owner could set up
electric vehicle charging stations
on their property
and make some income from reselling the electricity.
New Jersey and California
are using public-private partnerships to get solar panels installed,
for example, on school rooftops.
provides some estimates for the cost savings. Some example yearly
- Arizona State Capital Building = $24,266
- The Pentagon = $1.1 million
- Walmart SuperCenter in Bentonville, Arkansas = $179,300
Ford Rouge Plant
Largest green roof in the United States totaling 450,000 s.f. Ford saved
over $10 million on installation of a stormwater runoff treatment system.
Edible Green Roofs:
Some interesting examples of large rooftop
gardens are coming from
New York. Quotes from the article:
"Rooftop farms are in the midst of a boom here
in New York City…"
"Driving that boom – at least in part – is
New York City's Zone Green.
Proposed amendments to Gotham’s zoning code that continue
an inexorable march through the approval process, Zone Green
would permit solar panels, green roofs, storm water
systems, skylights and other green features on New York City buildings, despite existing restrictions within the 1961 code. Specifically with respect to rooftop
farms, Zone Green would allow a waiver of floor area and height limits for greenhouses on top of non-residential buildings."
A second rooftop garden example comes from
This one is a hydroponics greenhouse on top of a warehouse rooftop
that is harvesting 365 days a year. Quotes from the article:
"… hydroponics allow the urban farm to produce about 10,000 heads
of lettuce a week – roughly 100 tons a year. The controlled environment
agriculture uses 10 times less water and 20 times less land than
traditional harvesting methods."
"“We’re producing crops and delivering it within 24 hours,
definitely making it the freshest product on the market – the shelf life
is passed on to the consumer,” said Nelkin. “By being the freshest,
it’s also the most flavorful and nutritious.”"
Another agricultural example comes from
The Brown Palace hotel in downtown Denver has added 4 bee
hives and 65,000 bees to their roof and "can produce upwards
of 150 pounds of harvestable honey every summer". "Marcel
Pitton, managing director of The Brown Palace, said the honey
is like 'liquid gold' for the hotel. The honey is used in the restaurant
kitchen and as the basis for a lavender honey soap and a local beer,
made with the Wynkoop Brewing Company." The article states that
the beekeeping program started "three years ago, after the city passed
an ordinance in 2008 allowing hobbyists to own hives." Thus,
emphasizing the importance of planners working with the city to make
the conditions appropriate for roofs to become economic generators.
Rooftop gardening can be practical with the only change to the roof
being the addition of light weight planters. In 2011, "450 urban
agriculture planters were installed on the roof of the Palais des
congrès, allowing three partner restaurants (Crudessence, the
Palais’ catering service, and Intercontinental hotel) to learn
more about the basics of market gardening in cities and offer a
wide variety of produce on their menu for those who want to eat
locally and in season." (
As one example,
has an edible roof integrated system for growing food. It is lightweight
and can be installed on an existing roof without structural modifications.
The Montreal Convention Center installed this system over the summer
during the Ecocity World Summit 2011. The food grown went to local restaurants.
Here are 7 brainstorm ideas for how cities can help to turn the
city's unused rooftops into economic generators:
- Comprehensive Plan and Sustainability Plan
- One Page Briefs
- Free Advertising
- Zoning and Ordinances
- Open Space Reduction for Green Roofs with Additional Credit for Growing Food on Roof
- Make it Easy
- (Last Resort) Unused Rooftop Tax
First, make sure that the city's Comprehensive and
Sustainability Plans include using the rooftops in creative ways, so
as to encourage economic benefit to the building owner as well as the
city and its residents.
Second, create one page briefs. These would be
short educational brochures to inform the building owners of the potential
cost savings or income potential from different roof uses. Logistic, cost,
and other "barriers to entry" should also be noted to help the building
owner decide if one of the options is not appropriate for their building.
Third, do some free advertising for building
owners that implement a rooftop economic generator. For example, highlight
the business on the city web site or in the local newspaper. Use the
company as a case example highlighting what it took the company
to implement the economic generator. This could be framed as this
month's "Rooftop Economic Generator Winner". Over time, revisit
the company and have another article, or award, highlighting the
economic benefits that the company has generated from the rooftop effort.
Forth, make sure that all zoning and ordinances allow
these economic generators on the roof. For example, see
New York City's Zone Green
above. Also, for the edible rooftops, allowing food stands to be set up
around the city would help the food growers to sell the produce to residents.
Wheat Ridge, CO
claims to have one of the most liberal food stand policies in the U.S., allowing
food stands almost anywhere: "This ordinance updated the city's regulations
so that community garden (under the category "urban gardens"), farmer's markets,
and produce stands are now allowed in any zone district."
Fifth, which is a subset of Zoning and Ordinances, is to
allow green roofs to count towards open space requirements. This will give
developers more ground space for development, increasing their profit. This
should also increase city tax revenue (sales tax for increased business size,
increased property tax from larger building/more housing units).
Sixth, make it easy. For the most part, the building owner
is most likely not concerned about trying to run a second business. A big box
chain store will not want to change their focus. A small mom and pop business
may already be stretched on available time and brain power. To overcome this,
the city can do some of the leg work for the building owners. For example,
consolidate all needed forms and steps into a pre-packaged form. Consider the
case of an edible green roof, the city can have on hand a leasing contract that
the building owner can use with the farmer that wants to lease the roof space.
The building owner can then use these forms verbatim, or modify them as desired.
As a case study, look at
They have 7 pre-approved ADU packages that, if selected by the home owner,
allows for shortening the building approval process.
Seventh, create a new "unused rooftop" tax. This should only
be used if all other means to encourage effective rooftop uses fails. The concept
for this tax is that if a commercial building owner with a flat roof does not
implement an approved economic generator use for a "sufficient" percentage of
their roof, than the building owner has to pay a tax for this unused space. If the
building owner does implement an approved use for enough of their roof, then there
is no tax.
By looking up, cities can "create" additional space to plan
for the future. With some creating thinking, the unused space rooftops in the city
can become an economic generator.
Creating and improving the economic potential for communities
is always beneficial, but especially with the current great recession.
These two areas can be addressed by looking up. As an exercise, go
to a tall building in the city, look at a Google maps view of the city,
rent a hot air balloon ride, or in some way look down at your city.
In most cases, there will be a number of big flat roofs.
These roofs are a missed opportunity for economic growth of the community.