In American cities, green design is having a moment. Solar panels, porous pavement, and green roofs are all catching on as ways for developers to reduce environmental impacts of buildings.
But what happens when these features and other smart surface design elements are deployed throughout a neighborhood, or even an entire city?
A new report launched today in partnership with NLC’s Sustainable Cities Institute examines the community-scale benefits of buildings deploying these features — and makes a convincing case that local governments stand to gain billions through improved water management, energy efficiency, economic competitiveness, public health and even disaster mitigation.
Delivering Urban Resilience (report summary) is the first detailed analysis of the potential costs and benefits of city-wide smart surface technologies. Authored by Greg Kats and Keith Glassbrook of Capital-E, the report estimates that investment in these technologies could result in net present values of $1.8 billion in Washington, D.C., $3.6 billion in Philadelphia, and $540 million in El Paso, Texas, over a 40 year period. These quantified benefits include “reducing health and energy costs, increasing employment, and enhancing resilience and livability.”
These are eye-popping numbers — so it’s worth unpacking what this means for cities.
First, not all costs and benefits are created equal. Although costs come in the form of cold, hard cash, many benefits in economic analyses such as these are fuzzier. This is true whether a city is considering climate change benefits contained within this report or the value of a few seconds of travel time savings that might purport to justify an expensive new road. These might be important public benefits, but they don’t inherently generate new revenue.
However, Delivering Urban Resilience clearly demonstrates that the direct cash-flow benefits of smart surface features exceed the costs of operations and maintenance.
In the Washington, D.C., case study, the report estimates that citywide costs of smart surfaces would be $838 million for installation, operations, replacements, and employee training over a 40 year lifespan. The storm water benefits alone would be $1.17 billion for improved storm water quality, avoided treatment infrastructure, flood mitigation, and other factors that have a direct budget impact.
Essentially, the city is saving pennies in construction costs up front while wasting dollars cleaning up the mess at the end. Former General Services Administration administrator and Washington, D.C., COO Dan Tangherlini bought into the report because it “demonstrates there are cost-effective technologies… that would deliver billions of dollars in financial benefits to cities and their residents.”
Second, the report finds that the “benefits of city wide adoption of smart surfaces would be greatest in low-income areas.” The clearest example of this is utility costs. One of the key benefits of green roofs, “cool roofs”, and other building features is that they save on heating costs.
These features don’t just keep a building cool — on a community scale, they can actually lower the air temperature, combat heat island effects, and improve air quality. This is crucial to low income populations, who may spend up to 15 percent of their income on utility bills. The report points out that “even a modest city step such as adoption of a cool roof procurement policy for affordable housing would generate substantial net benefits.”
Less directly, city policies that promote smart surfaces or high performance design are too often equitable only in theory. For example, many cities offer incentives for developers to include optional green building design features. In practice, these incentives follow the normal flow of investment and development into wealthier areas while low-income populations are served by developers doing the bare minimum.
By embracing the fact that benefits exceed costs, cities can dispense with the notion that these are optional luxuries and begin to require smart surfaces be integrated into all building and infrastructure projects, raising the bar for everyone.
Finally, integrating smart surface features into a community can help offset the impacts of growth and improve urban resilience. It is no secret that the cost and frequency of disasters is increasing. A small portion of this can already be attributed to observed changes in the climate, however most of it is caused by the unintended consequences of growth since impervious surfaces — roads, parking lots, and buildings — increase regional hazards.
The connection between pavement and flooding was dramatically highlighted when Hurricane Harvey struck Houston as water quickly flowed into the reservoirs and bayous that couldn’t withstand the load. The same pattern of sprawl, pavement, and accelerated storm water has exacerbated flash flooding in cities throughout the US, creating new flood risks where none previously existed.
Moving forward, the NLC Sustainable Cities Institute is excited to collaborate with the report authors and several of their national partners to share this work. The technology, design, and maintenance of these features have all evolved rapidly, and a lack of understanding can severely limit the effectiveness city programs. Together, we will educate elected officials and staff, and develop simple, affordable models for cities to strike the right balance.
Cooper Martin is the program director of the Sustainable Cities Institute at the National League of Cities.