This article highlights the challenges of the transition from natural gas in Philadelphia to renewable energy. Philadelphia Gas Works (PGW) — the largest municipal gas utility in the country -- has a pipe network that has expanded over the past 185 years to encompass 6,000 miles of gas mains and service lines. With Philadelphia's ambitious net-zero greenhouse gas emissions goal by 2050, and with PGW accounting for 22% of the city's greenhouse gas emissions, it's quintessential that conversations regarding transitions take into account the city's infrastructure for natural gas, PGW's workforce, and the most vulnerable Philadelphians who are increasingly propping up the city's expensive gas grid.
Even before the pandemic led to a recent spike in unpaid bills, many Philadelphians faced an energy affordability crisis. Philadelphia has the highest poverty rate of any major U.S. city; roughly one third of PGW’s customers are low-income. To be equitable, any transition for the utility must “make sure every last person reliant on natural gas has a way to keep warm in winter, cook their food, and heat their water,” said Elizabeth Marx, executive director of the Pennsylvania Utility Law Project, which represents the interests of low-income utility customers. “If you’re talking about shifting away from a system that’s been built out with ratepayers for decades, you can’t shift away easily without leaving people behind.”
As more affluent customers abandon gas to install heat pumps and other clean-energy upgrades with higher upfront costs, many advocates for a “just transition” worry that lower-income ratepayers will be left to foot the bill for maintaining PGW’s aging gas infrastructure.
“What you want to avoid is the situation where you have to maintain and spend money on the whole system, even while you sell less gas,” said Mike Henchen, who leads the building decarbonization program at the energy thinktank RMI.
Meanwhile, some of that maintenance can’t wait, for safety and environmental reasons. In December 2019, a leak from a 92-year-old gas main caused an explosion that killed two people and leveled five rowhouses in South Philadelphia. The methane in those leaks is also a potent climate-warming agent; a 2019 study that sampled air over Philadelphia and five other East Coast cities found methane levels 2.5 times higher than suggested by emissions inventories from the Environmental Protection Agency.
“Gas utilities are in a difficult bind,” said Audrey Schulman, the founder and co-executive director of HEET, the nonprofit that initiated the Massachusetts geothermal project. “At the same time that they have to decarbonize, they have to replace these aging gas pipes.”
PGW is studying various paths to decarbonization. One option is to keep it's pipe-based system and add more low-carbon gas molecules to the mix (renewable natural gas). Several recentstudies have found that fully electrifying buildings is a lower-cost way to decarbonize than going the “green molecules” route. In one, researchers estimated that the monthly cost of running a heat pump would range from $34 to $53, whereas running a gas furnace on renewable natural gas would cost $160 to $263. But even if operating a heat pump is likely cheaper over the long run than firing a furnace with biogas, the upfront cost of buying and installing one — including upgrading wiring and circuit breakers to handle heavier loads — remains high relative to a conventional gas heater. Those costs are still well beyond what many Philadelphians can afford.
Others still see a role for pipes in the city’s energy future. This summer, Eversource Gas, the investor-owned private utility in the Boston area, will break ground on the first demonstration of HEET’s innovation. The nonprofit has developed a concept called the GeoMicroDistrict, which would link buildings on a given street or block into a networked geothermal energy system. The system is powered by ground-source heat pumps, extremely energy-efficient devices that use water as a medium for sharing thermal energy between buildings, sending heat where it’s needed and away from where it isn’t. The geothermal districts tap the constant temperature of the ground, and can themselves be further linked together into larger networks.
The biggest upfront costs are associated with installing the system, including the drilling of shallow, six-inch-wide boreholes; after that, operating costs are low. Utilities like PGW could absorb those steep capital costs and spread them out over time and over their wide user base, taking advantage of economies of scale, said Zeyneb Magavi, the co-executive director of HEET. The geothermal pipes could be laid in the same rights-of-way already used for gas pipes. Geothermal systems could also preserve more jobs, she added, leveraging the expertise of utility workers, many of whom are trained to install the same kind of plastic pipes.
Jonathan Mingle and Yale Environment 360, "Cities confront climate challenge: How to move from gas to electricity?", contributed by Morgan Sarao and Morgan Sarao, The Energy Rights Project, Platform for Experimental Collaborative Ethnography, last modified 3 May 2021, accessed 13 May 2021.