Left in the Dark

Hurricane Sandy Was a Stark Reminder of the Vulernability of Our Electrical Grid
Although Hurricane Sandy left much of lower Manhattan dark, cold and without electricity, some 5,000 residents of the Chelsea area’s Penn South Cooperative had power, lights, heating, elevators, Internet and television. That’s because Penn South has its own cogenerating electric power plant, connected to the electrical grid but able to operate independently. Almost a decade ago, in 2003, during the last big summer blackout, the same thing happened, albeit for a shorter time. During that blackout, I viewed the darkened city from a well-lit and fully functioning Penn South apartment, with sympathy for those without power, and wondered why there weren’t many more local power-generating systems like this one throughout the city.

The message seems clear nine years ago: America’s electric grid is outdated, dangerous, subject to failures. Decisions were made at the speed of telephone calls when changes in electrical transmission were happening at the speed of light. Nationally, America needed a smart grid; regionally, it needed town-sized area microgrids where electrical power is produced and used within a few miles and single buildings or a small group of buildings had off-the-grid electrical cogenerating systems, like Penn South’s.

But Penn South uses diesel generators, so widespread duplication could increase the city’s air pollution. A seemingly good alternative would be rooftop solar photovoltaic (PVC) energy systems. Today’s are reliable and built to withstand winds at 120 mph and could provide enough power for essentials.

In a city like New York, full of tall buildings, the main limitation is the percentage of a day when a roof is shaded by a taller building or other structures. Even a group of seemingly widely spaced elevators housing on a rooftop can shade the solar devices enough as the sun passes overhead to make the PVC units nonfunctional.

For storage for small systems like a single building, existing batteries are good enough right now to provide homes with 24-7 power. An even better storage seems theoretically possible: when the sun is out, use excess electricity to separate hydrogen and oxygen that make up water. The hydrogen can be stored and used directly as fuel. But that isn’t the easiest fuel to store and work with. The real breakthrough will come when petroleum chemists work out how to combine that hydrogen with carbon and make natural gas, or even go a step further and make diesel fuel in place. A step in that direction has just occurred: On December 3, Louisiana agreed to have the first U.S. installation of a chemical plant that converts natural gas to diesel.

Solar photovoltaic systems are surprising powerful. When I wrote Powering the Future: A Scientist’s Guide to Energy Independence in 2010, I used the electrical production from in-place operating solar energy facilities in San Francisco. From these I was able to calculate that if 6.5% of the land area in San Francisco had those PVC solar facilities, all of the city’s residential electricity would be produced. I didn’t measure it, but I believe that’s less than the percentage of the land in that city covered by roofs of buildings.

I didn’t have similar information to make those calculations for Manhattan, but at that time the largest PVC system in the world was in Bavaria, Germany, not known especially for a warm, sunny climate. That system produced 10 megawatts on 62 acres. If that system had been reproduced on about 3.5% of Germany’s land area, with no better weather than Bavaria’s, an amount of energy equal to all the energy Germany was using—not just electrical energy—would have been produced.

The lesson was clear in 2003, but it has gone pretty much unheeded. The extended blackout in lower Manhattan when it was getting colder should shake up our thinking about the basic structure of our electrical distribution system. Mayor Bloomberg said we should rebuild New York City smarter, having learned the lessons from the effects of Hurricane Sandy. If only we can learn this time what seemed clear in the blackout of 2003, we will have moved ahead and can expect to do better the next time a major disaster hits.