Washington, Nov 15 (IANS/RIA Novosti): The electrical power grid in the US is vulnerable to terror attacks, according to a report made public Wednesday by the National Research Council (NRC), an independent think-tank on public policy.

"Power system disruptions experienced to date in the United States, be they from natural disasters or malfunctions, have had immense economic impacts," said M. Granger Morgan, head of the department of engineering and public policy at Carnegie Mellon University and chair of the committee that authored the report.

More than 100,000 people are still without power after Hurricane Sandy ravaged the northeastern coast of the US two weeks ago. And while officials say it is still too early to predict the full measure of the storm's impact, total costs from the electrical outages alone could stretch beyond $500 million, according to several utility companies.

That amount pales in comparison to the economic effects of a terrorist attack on the power grid, researchers say.

"Considering that a systematically designed and executed terrorist attack could cause disruptions even more widespread and of longer duration, it is no stretch of the imagination to think that such attacks could produce damage costing hundreds of billions of dollars," said Morgan.

The 164-page-report depicts an old, feeble power grid, which if targeted by terrorists, could cause unprecedented blackouts in both duration and extent. The system is especially vulnerable to multiple failures following an attack, researchers said.

"Many of the transmission lines are 60 to 80 years old, and in a lot of places, the equipment comes from our grandparent's era," said Susan Tierney, an energy expert and one of the report's authors.

Additionally, Tierney said many important pieces of equipment lack the improved technology that could cut restoration times in the event of an outage, and in some cases, prevent outages from occurring in the first place.

The report cites major cascading blackouts in the southwestern US in 2011 and in India earlier this year, as examples of the need to expand and upgrade current electrical systems.

The NRC also highlighted vulnerable US communications systems, censors, and controls that could be susceptible to cyber-attacks over the internet or by the direct penetration of remote sites.

"The bottom line is that as a society we are increasingly dependent upon the electric gird, not just charging our cell phones and computers, but our financial system and public safety systems," Tierney said.

The report, initially requested by the US Department of Homeland Security (DHS) as part of its efforts to protect the nation's critical infrastructure, was completed in 2007.

Upon review, the DHS ruled the Research Council's findings as classified. More than four years later, the report was later cleared for public release this fall, after the Research Council requested an updated security classification review.