Despite All Those Three-Pronged Plugs, The Fight Between AC And DC Power Is Still On

Nov 30, 2015

More than a century ago, the fight between George Westinghouse in Pittsburgh, and Thomas Edison in West Orange New Jersey, over whose power system was better, ended with Westinghouse and alternating current as a clear winner. But research at the University of Pittsburgh has rekindled that fight.

“Basically Edison lost because the direct current grid that he envisioned required that you have a power plant every mile or under best circumstances every two miles,” Jill Jonnes, author of “Empires of Light,” said after attending a recent conference in Pittsburgh exploring the rebirth of DC power and the possibility of micro power grids.

At the time, those small grids would have meant a smoky, coal-fired boiler in every neighborhood.  Instead, Westinghouse, with the help of Nikola Tesla, harnessed the power of Niagara Falls and shipped the abundant electricity to the factories in Buffalo. 

Now fast-forward 125 years, past the discovery of semi-conductors that make it possible to send DC power long distances more efficiently than you can AC power, past the advent of all those electronic gadgets and LED lights in your home that actually are run on DC power.

“You couple that with new resources like photovoltaic, which are a DC entity inherently, and you have a better match now of DC integration from resource all the way down to how we use electricity today,” University of Pittsburgh professor Gregory Reed said. Reed is among the world’s leading proponents of direct current. 

Places such as China, where electricity infrastructure is still being expanded, are opting for DC systems along side AC systems in part because of its new efficiency, and in part because it uses less capital to send power long distances over a DC two-wire system rather than an AC three-wire system. 

“We are starting to see more and more growth of distributed resources,” said Reed who believes micro grids provide a greater level of resiliency following natural or manmade disasters.

Security experts at DARPA have called for more research into protecting power grids from hacker attacks that could, with one properly placed computer virus, shut off power to huge sections of the U-S and Canada. Micro grids could make such massive attacks nearly impossible. 

That is one reason why this month Pittsburgh-based Duquesne Light gave a $500,000 grant to the University of Pittsburgh to research the feasibility of connecting neighborhood-sized DC systems to the larger grid. Much of the money will be used to research and build switching systems to allow for reliable flow of electricity among the micro grids and the current AC power grid.

“What remains to be seen is really the balance between alternating current and direct current in its make up of the electrical system,” Duquesne Light Senior Manager of Strategic Planning Ben Morris said.

This signifies a major shift. In the past, large generators and distributors were very protective of the system.

Now developers of the Civic Arena site and the Almono site in Hazelwood are toying with the idea of including micro grid DC infrastructure. But Reed said the idea of retrofitting your home to run on DC is about more than just technology. 

“We have to put in codes and standards and certifications around how we do that,” Reed said. “Today if you went to an electrician and said I want a new home to be built and I want it to have all DC in my house he would not know exactly what voltage to put it at because there is no standardization around that yet, he would not know what size wiring to use, he would not know exactly what type of switches he could use.”

Having said that, Reed believes homes will be the first place where all-DC systems become a reality, possibly in the next five years. Data centers could also be low hanging fruit, and the Pittsburgh-based trucking firm Pitt-Ohio is working on new DC systems and battery-powered trucks. 

Reed gives a copy of Jonnes’ book to all his grad students to make sure they know the history, on which they are building. If he has anything to say about it the next winning system will once again come out of Pittsburgh.

On the Grid reporter David Conti contributed to this report. Read more about this and other stories at the website of our partner Trib Total Media