Green Space: Dense and decentralized

An empty parcel between shotgun houses in the Smoketown neighborhood | Photo by Elijah McKenzie

This is the fourth article in a four-part series that examines the complex relationship between green spaces, public policy and the urban heat island effect, while highlighting citizen-led strategies to mitigate the sweltering heat.

Density is one of the crucial elements needed to make a city safe, walkable and accessible to everyone. It’s also necessary for the preservation of pre-existing green space along the margins of the city, where arable farmland has been frequently bulldozed and transformed into cul-de-sac housing expansions.

History has shown just how oblivious these types of developments have become, particularly because we now know they turn local watersheds toxic and threaten to destroy what little forest acreage we have left. This practice also exacerbates the city’s heat island problem and contributes to the vacant property issues that have persisted in the urban core for generations.

One might think that abandoned lots would present a sort of a blessing in disguise because those empty gaps between buildings could facilitate tree growth without obstructing power lines. Local architect Steve Wiser thinks that would be a bad idea.

“I would prefer to infill these vacant tracts with new housing, which would be more affordable, than expanding out into the countryside, removing more green space,” Wiser said. “Fortunately, it appears demographics tend to be indicating the younger generation prefers living closer to the urban core than the previous generations.”

To better understand the density dilemma, compare the number of blighted parcels in downtown Louisville to the number of housing developments being built in the suburbs. There’s certainly an inverse relationship that leaves core districts with far fewer investment dollars than their East End counterparts.

Urban sprawl also necessitates the construction of more asphalt, highways and power lines, bringing an uptick in air pollution, miles driven and trees removed for utility easements.

For cities without growth boundaries, the solution to this problem has often come by means of park creation. This was the case with The Parklands of Floyds Fork, which, among other things, endeavored to curb sprawl on Louisville’s Eastern border by claiming land for public space and wildlife.

The Parklands of Floyds Fork is the largest fully funded metropolitan parks project in the country. | Photo by James Natsis

As is the case with many urban design strategies, disparities seem to persist. The American Journal of Preventive Medicine published a study in 2016 which discovered that parks in poorer neighborhoods tend to be smaller and have fewer amenities than parks in wealthy areas.

While small, short-term investments could make parks more attractive to adjacent neighborhoods, a large reason for the lack of interest among low-income residents could stem from the material conditions of the parks themselves.

Facilities like tennis courts and baseball fields usually come with classes and events designed to increase social and physical activity, most of which are more widely available in affluent areas. This is a yet another example of how green spaces are disproportionately distributed across certain demographics.

A report from the UC Berkley College of Environmental Design offers an alternative perspective to the topic. Authors Jennifer Wolch, Jason Byrne and Joshua Newel warn that redressing the lack of green space in low-income areas could inadvertently create what they call a parks-poverty paradox.

“As more green space comes online, it can improve attractiveness and public health, making neighborhoods more desirable. In turn, housing costs can rise,” they wrote. “Such housing cost escalation can potentially lead to gentrification: the displacement and/or exclusion of the very residents the green space was meant to benefit.”

Although parks can be used to rectify certain socioeconomic inequalities, it is not a silver bullet solution to the problem of urban heat.

Louisville’s new tree ordinance would still need to take a firmer stance on utility easements — particularly regarding the concentration of utility poles along pedestrian thoroughfares — to ensure a proper tree-to-pole ratio that doesn’t obstruct the existing tree canopy or impede human-scale traffic.

Rendering of what a decentralized grid would look like | Courtesy of E. ON Energy

There are a few ways to achieve this. In lieu of an underground energy network, a decentralized grid would be beneficial in that it wouldn’t necessitate the construction of new utility poles or overhead power lines.

Power grids are considered “decentralized” when energy is produced close to where it will be used. Rather than sourcing energy exclusively from a distant power plant that transmits electricity through a central grid, a decentralized approach opens the door for utility customers to produce their own energy that can then be redistributed to others.

Anyone remember the ice storm of 2008? Nearly 60 percent of Louisville Gas & Electric customers were without power for more than a week due to the fallen branches of urban trees. Entire portions of the city’s tree canopy were gutted because their fallen branches were responsible for the widespread blackouts. With a decentralized system in place, these kinds of power failures would almost cease to exist.

Customers could fall back on their own renewable sources in the event of a storm or blackout, and with a decentralized grid, individuals could share or sell surplus electricity to their neighbors more efficiently than through a traditional utility network.

However, Kentucky is a “closed grid” state meaning only utilities can sell electricity to end users, effectively shutting everyone else out of the distribution process. All renewable energy generated locally (e.g. solar panels and biodigesters) can only go toward the purchase of more coal-fueled electricity, for which LG&E and Kentucky Utilities will only apply credit toward the consumer’s future electric bill.

Cost of underground lines compared to standard overhead installation | Courtesy of U.S. Energy Information Administration

In 2015, more than three-quarters of Kentucky’s net electricity generation was produced by coal. If commercial customers decide to generate their own renewable energy and reduce the amount they purchase from the utility, they could be penalized with a rate or tariff increase, further reducing the opportunity for savings or return on investment.

Once again, outdated laws have allowed utility companies to discourage potential competition. Despite this challenge, decentralized generation still continues to be far more efficient than centralized generation in nearly every way.

How does this effect utility poles and overhead wires? In our current state, a central power plant distributes energy through high voltage transmission lines — carried by large towers that often cut through miles of rural forests — that connect to regional substations. Electricity is then stepped down and sent to individual neighborhoods via power lines.

According to a research report led by professor Paul Hines, formerly of the National Energy Technology Laboratory, communities that have access to “open grid” systems can secure transmission feedbacks between substations, which can supply electricity directly in response to localized demands. This method fosters the development of energy-independent zones that can subsist without the need for excessive, miles-long utility easements that transmit power from remote power stations.

“I remember when Western Kentucky Gas would finance your gas stove or gas heater at zero percent interest,” said Bill Bivins, founder of the Louisville-based energy company One World Clean Energy.

“Utilities could profit by leasing rooftops for solar power, or finance cogeneration or tri-generation,” he added. “A decentralized grid could be managed in a way that would create a profitable symbiosis between the utility and customer.”

Microgrid technologies | Graphic courtesy of Raytheon

Installing solar panels or other microgrid systems tends to be relatively costly at first, but special feed-in energy tariffs — payments to customers for the renewable electricity they generate — would help create more stable pricing. Ideally, we want to reach a point where localized energy sources can provide widespread distribution without the use of government subsidies, at which point the system is considered to have achieved “grid parity.”

Combined with a stronger, more comprehensive tree canopy ordinance, a decentralized structure would help ease the strain on local trees by rendering most aboveground infrastructure unnecessary, consequently diminishing the problems associated with utility poles and power lines.

Major cities across the United States have public utilities that have incentivize renewable energy at the consumer level, including perks for customers who put solar panels on their roof or a windmill on their farm. These initiatives should be considered a first step toward the larger goal of liberating Louisville’s tree canopy from the undue burden of being surrounded by so many utility easements.

From opening Kentucky’s utility grid to planting trees in areas where they can feasibly thrive, the ideal of reducing urban heat is not an impossible dream. This series has featured a number of urban cooling strategies that have been tested elsewhere and can easily be implemented right here, right now.

With each passing year, Louisville’s heat island will only continue to get worse, but it doesn’t have to be that way. Cities are supposed to be for people. It’s time we designed them with human interests in mind.