The city is aiming to find out whether solar energy farms might be a reasonable use for its old, closed landfills.
Tucson is one of 26 cities across the country selected to work with the U.S. Environmental Protection Agency and the U.S. Department of Energy to test the feasibility of putting renewable energy projects on its landfills.
The city has 16 old landfills, covering about 1,500 acres, that would otherwise not easily be redeveloped.
The yearlong study will focus on five of them, with a particular emphasis on the 61-acre Vincent Mullins Landfill near Speedway and Kolb Road, which was closed in 2007.
Joe Salkowski, a spokesman for Tucson Electric Power, said while the utility company has looked at city landfills as a potential site for solar arrays, landfills bring with them inherent complications.
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There's no telling what kind of material is in there. The ground can sink as the material settles. The sites tend to generate gases from decomposing materials - which is why sites like Vincent Mullins have a gas extraction facility to burn off methane gas.
"If those issues could be addressed in a way that would allow for the construction of a cost-effective solar array, city landfills would be very attractive to us," Salkowski said.
Jeffrey Drumm, a project manager with the city's Environmental Services department, said the city wants to explore whether private companies could set up on the sites.
But he said the city is also interested in looking into whether a project could supply enough energy to power the landfill and nearby public facilities, such as Udall Park and the Ward 2 City Council office.
In addition to neighborhood compatibility, he anticipates the study will help determine how to place panels on the landfill and how much energy can be produced.
Drumm said that if the feasibility study shows solar would work, that would give him the ability to ask the city manager to look for funding to make it happen. Armed with data from the National Renewable Energy Laboratory, he said, it would give the city more credibility in making a pitch.
Right now, he noted, there are plans on at least some of the sites to put in dog parks or pocket parks. That hasn't happened because the funding hasn't materialized, he said.
"The city is always looking for ways to make this land usable - not just to make sure it isn't an eyesore, but that it's actually usable," he said.
The other sites include the Harrison and Irvington landfills on the far southeast side. Investigators will also look at the Silverbell Landfill, as well as the Ryland Landfill at the corner of Ajo Way and Interstate 19.
The federal studies, at a cost of $1 million nationwide, will also evaluate wind energy, geothermal and biomass - which is essentially where items like trees, crops, yard waste are ground up for energy. Drumm said he doesn't think any of those other alternatives will prove feasible here, since the urban areas of Tucson don't have enough wind or seismically active hot spots, and where the rate of tree materials is relatively sparse.
The promise, he said, really lies in solar.
The EPA notes that renewable energy projects on similar sites have been successful in the past, with some 20 energy projects under way already on contaminated sites.
A six-megawatt solar array went up in 2010 on a Superfund site in Sacramento County, Calif., with the energy powering the cleanup of the site. A 10-megawatt solar installation in 2010 was constructed on a brownfield site in Chicago.
The agency notes landfills and other contaminated sites often are ideal for redevelopment because infrastructure like roads and water are often available already and the sites often have the necessary zoning requirements. They can also take the stress off undeveloped lands and in some cases, provide job opportunities.
No city money will be spent on the evaluation.
Did you know
The Vincent Mullins Landfill was named for a longtime city sanitation supervisor.
Contact reporter Rhonda Bodfield at email@example.com or 573-4243.