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Since 2006, Portland Community College has been following a plan to renovate its Sylvania campus so that it is able to produce all of its own energy on-site.

Now, that net-zero goal is on hold.

The college had planned to use its 40-year-old boilers to back up a system that would use renewable energy, such as a fuel cell and anaerobic bio-digester, and convert campus waste into electricity and heat. But the boilers are failing, according to Tim Donahue, director of facilities for PCC’s Sylvania campus.

“We originally thought the boilers would last,” Donahue said. “Now we’ve got major failures and are having to do some further research. It’s more than just flipping the switch and going net-zero.”

The problem, Donahue said, is that Sylvania must have a backup energy system. According to Keith Skille, associate principal with GBD Architects and Sylvania project manager, new technologies like fuel cells often have to be taken off-line for service, and in the meantime, something needs to keep the campus running.

Now, the college needs a backup for its backup system.

PCC officials are considering whether to replace Sylvania’s old boilers with newer, more efficient boilers and use either a combustion turbine or a cogeneration system as the primary energy system. A fuel-cell upgrade could take place in the future.

In an assessment performed by Gerding Edlen Sustainable Solutions, it was recommended that the college replace its current boilers with a cogeneration system and use the fuel cell as a secondary energy source; however, that goal has been pushed back, according to Renee Loveland, GESS project manager.

“There were several options for the college to meet their ultimate net-zero goal, including the fuel cell and cogenerator,” said Loveland. “At this time, the college is not committed to making all of those improvements. This happens all of the time in the world of green industry. There are financial constraints and ongoing operation constraints.”

If Sylvania’s boilers were replaced with a 1.1-megawatt cogeneration system that converts mechanical energy to electrical energy, the system would provide nearly 30 percent of the total campus energy and the majority of its hot water. But cogeneration systems also need one or two days of downtime every 18 months for maintenance. If the college were to rely on only the cogeneration system and fuel cell, and the fuel cell failed during maintenance, there would be no backup.

“We don’t want to close the school under any circumstance,” said Linda Gerber, president of PCC’s Sylvania campus. “As we have gotten into the weeds of implementing our stage-one strategy, we’ve run into a challenge. All three of our original boilers have problems that could make them fail. We don’t want all of our energy-producing capacity to be down without anything to back it up.”

The fuel cell/anaerobic bio-digester system would convert methane into electricity, and require the equivalent of either 6 million pounds of sewage waste or 18 million pounds of food and landscape waste monthly. The Sylvania campus doesn’t produce that much waste, so PCC would need to reach agreements with the city and other facilities to supplement its waste needs.

Another option, a combustion turbine, also has problems, Donahue said. A combustion turbine is a rotary engine that extracts energy from a flow of natural gas.

Donahue said Lewis & Clark College in Portland purchased a combustion turbine to power its campus. But maintenance costs have led the college to rely on its boilers for heat and electricity for some time. Combustion turbine motors last only about three years, Donahue said, and the control panel often fails thereafter.

Also, a combustion turbine is fairly noisy, and would require additional construction to insulate the room that held it.

Plus, both combustion turbines and cogeneration systems use fossil fuels, which contradicts PCC’s ultimate goal to generate all of its electricity from renewable sources. The end goal for Sylvania, Gerber said, is to be completely energy independent. PCC previously signed on to the American College & University Presidents’ Climate Commitment, which requires colleges to reduce their greenhouse gas emissions by 80 percent by 2050.

“The cogeneration system would still be an improvement, and our new boilers will be more energy efficient,” Gerber said. “We probably would have needed the new boilers in any case; we just didn’t expect it to be so soon. There is not a long history of usage with fuel cells, and we want to spend money wisely on a technology we can trust. We’re aiming for net-zero in a staged way.”