Interdisciplinary Engineering: Paul Cloyd and the Greening of Alcatraz

As Branch Chief for Design & Construction with the National Park Service, Paul Cloyd has taken on some pretty high-profile projects.

Paul Cloyd

Paul Cloyd

Working out of the Denver Service Center, the NPS's central planning, design, and construction management project office, the 1976 IDE alumnus (Architectural Engineering) and 2001 recipient of Purdue's Outstanding Interdisciplinary Engineering Alumni Award oversaw the relocation of the historic Cape Hatteras Lighthouse and was a team member on the restoration of the Russian Bishop's House in Sitka, Alaska, and on the restoration of the St. Philomena Catholic Church in Hawaii's Kalaupapa Leprosy Settlement.

His latest project concerns one of the most notorious sites in the United States: Alcatraz Island, home, from 1934 to 1963, of the maximum-security Alcatraz Federal Penitentiary and now an NPS landmark that receives 1.4 million visitors a year. (The island is part of the Golden Gate National Recreation Area.)

“Alcatraz has run off diesel generators since the 1970s,” Cloyd says, “and that meant the fuel had to be shipped in. The National Park Service was concerned about the possibility of oil spills in the San Francisco Bay, along with the cost of the fuel.” Indeed, the 1,200-gallon-a-week supply of diesel generated electricity that cost about 76 cents per kilowatt-hour, or about six times the national average.

PV panels at Alcatraz

PV panels at Alcatraz

In 2010, with funding from the American Recovery & Reinvestment Act, Cloyd's team began coordinating work on a plan to install a solar-powered microgrid on the prison’s three-story cellhouse, as the island’s primary power source. In partnership with the Department of Energy’s National Renewable Energy Lab, the National Park Service designed a 305-kilowatt photovoltaic (PV) system consisting of 959 crystalline-silicon solar panels to power computers, phones, appliances, pumps, indoor and outdoor lighting, and a few large peaking loads, such as an elevator in the cellhouse and a lift at the dock. The PV array is attached to two 2,000-amp-hour battery strings (housed in the historic Quartermaster Warehouse) and an inverter plant, located in the powerhouse.

“We work closely with cultural resources staff and the state historic preservation officer to make sure that we’re not doing anything detrimental, either culturally or environmentally,” says Cloyd. To protect the island’s bird sanctuary and hatchery, NPS installed temporary screens along the cellhouse so that the birds couldn’t see, and thus be disrupted by, work on the installation. An earlier plan for a solar-powered system on the island was scotched, in part, because the PV system (if placed where intended) would have been visible from the prison exercise yard—a jarring anachronism for a site that famously incarcerated Prohibition-era gangsters like Al Capone and Machine Gun Kelley.

Alcatraz Island

Alcatraz Island

Fully implemented in 2012, the PV system is expected to produce nearly 400,000 kilowatt-hours of electricity a year, has reduced greenhouse gas emissions by about 337,000 kilograms of carbon dioxide a year, and has reduced the time the diesel generators run by about 60 percent. The drastic reduction in diesel use has meant much less corrosion of pipes and smokestacks and less pollution in the bay (although the new panels did attract more bird droppings than expected).

“The project has been very gratifying,” says Cloyd. “I can monitor the system from my computer. And it’s great to say that diesel generators—which used to run 24/7—are only needed as a backup now. That was our goal.”