Five years after the worst blackout in U.S. history, the country has strengthened the reliability of the electricity grid. But new challenges in demand, investment and energy resources leave the system vulnerable to another large-scale failure, experts and government officials say.
"The events that led to the 2003 blackout are now much less likely to occur," said Richard Sergel, president and CEO of the North American Electric Reliability Corporation, the nongovernmental agency overseeing reliability enforcement of utilities. But, he added, "We worry that we won't be able to meet consumer needs without a significant investment of infrastructure."
A joint U.S.-Canada task force concluded that a combination of human error, equipment failure and inadequate monitoring throughout the northeast were responsible for the 2003 outage which left approximately 50 million people across eight states and Ontario without power. The blackout also resulted in about $6 billion in business losses.
ABC News' Brian Ross first reported how the outage began when trees hit a power line along Akron-based First Energy's line. Further ABC News investigation found that First Energy had a long record of troubling safety, operational and financial problems.
Union workers complained the company had cut back on maintenance and transmission lines at other facilities. And its Ohio nuclear plant had to be shut down in 2002 because safety violations were so serious, including a football-sized hole in the top of the reactor vessel.
First Energy has said that the task force's report overemphasized the company's culpability in the power failure and that there were weaknesses in multiple companies across the grid. Since the 2003 outage First Energy has said it upgraded its computer systems, training and tree-trimming.
That outage sparked a serious transformation of the electricity market. The biggest change was the development of federal oversight for the reliability of major transmission lines and generation plants through the Energy Policy Act of 2005.
That law gave the Federal Energy Regulatory Commission authority to develop reliability standards and impose fees on those utilities that fail to meet them - a power it delegated to NERC.
The list of new standards is lengthy but they include requirements that companies do more to prevent trees from hitting power lines and maintain greater power back up to prevent small outages from spiraling. It made training for system operators mandatory and required that regional agencies coordinate planning and operation between utility companies, instead of the haphazard communication that existed in 2003.
Last June, these standards became mandatory. The agency has already forced many utilities to fix violations. Only two were severe enough to require a fine, both at least in part for failing to take care of vegetation too close to power lines.
Already there has been an up tick in investment in new transmission lines and development along the electric grid.
"We've made it national and we've made it mandatory with enforceability through fines," said Scott Hempling, executive director of the National Regulatory Research Institute, which tracks the electricity regulation and market. "That gives everyone cause for optimism."