By Susan Tompor

Bet if I asked, the odds are good that many people could tell me to the penny what they just paid for a gallon of gas.

By Javier E. David

If consumers have noticed their utility bills falling, it may not be a figment of their imagination. Although surging natural gas production in the U.S. has yet to result in lower gasoline prices, it has had one benefit already: curbing or even cutting power costs.

By Javier E. David

If consumers have noticed their utility bills falling, it may not be a figment of their imagination. Although surging natural gas production in the U.S. has yet to result in lower gasoline prices, it has had one benefit already: curbing or even cutting power costs.

Generating electricity has been made more efficient because of inexpensive and abundant natural gas. The shale gas boom in the U.S. has left the world's largest economy awash in the power source, which is used by utilities to generate nearly 25 percent of U.S. electricity, according to data from the Edison Electric Institute.

Utilities have traditionally used coal to generate electricity, but the abundance of relatively inexpensive natural gas has given power operators an incentive to shift away from using the black rock, a key contributor to carbon dioxide emissions.

That has created an added benefit in both the residential and commercial use of electricity, observers say. The bounty of shale gas has helped contain electricity prices, which allows power companies to avoid having to pass along higher input costs to the average consumer.

According to a 2012 study by Resources for the Future, an independent research firm, the supply of natural gas "will substantially reduce retail electricity prices over the next 20 years."

Under various scenarios, the think tank expects the natural gas boom could help spur electricity savings of anywhere between 1.4 and 5.7 percent, depending on the year.

While the RRF says commercial customers will derive the most savings from lower costs – simply because of the sheer amount of electricity they use – all U.S. electricity users can expect to save at least $70 billion through 2020. Over the same time frame, residential consumers may save about $25.8 billion.

"As the price of natural gas falls, the cost of purchasing that natgas, or purchasing the power also falls," explained Jim Hempstead, senior vice president of global project and infrastructure finance at Moody's Investors Service.

"Utility companies, all else being equal, will pass on the savings to consumers in lower rates," he said, adding that electricity bills will be "slightly lower or more flattish."

The situation is a win-win for all, Hempstead added, because consumers get lower or stable electricity rates, companies can produce more electricity at lower costs, and regulators aren't forced to crack down on suspected price-gouging.

According to Donald Henschel, a senior market analyst at IHS, utilities that once used natural gas only for "peaking power plants" – operated at times during the day when energy usage was highest – have now switched to broader use of natgas.

Because natural gas is inexpensive, and easier to turn on and off than coal because of its composition, it helps to contain the costs passed along to consumers.

"With natural gas prices coming down so much it's a viable solution," Henschel said in an interview. "For base generation [times of the day when power is at an ebb], coal was historically a more affordable solution. Now with natgas so affordable, you can run combined cycle base load generation plants burning natural gas."

That transition is helped by the rising costs of burning coal, which is being made more expensive by regulations governing clean energy, he added.

There is a risk to that scenario, however. Henschel points out that natural gases could easily spike – which could easily put upward pressure on electricity costs and reverse the virtuous circle. This is not outside the realm of possibility, as natural gas prices have been trending upward since late last year.

The U.S. will put into circulation a newly designed $100 bill in October that aims to thwart counterfeiters with advanced security features, the Federal Reserve said on Wednesday.

The new greenbacks still bear the portrait of Benjamin Franklin, the 18th century luminary who helped found the new American republic.

The changes in design are mostly in anti-counterfeiting features such as a blue three-dimensional security ribbon and alternating images of bells and the number 100 that move and change as the viewing angle is tilted.

The new notes, which cost slightly more to produce, also feature a bell image inside a picture of an inkwell that changes from copper to green when tilted, as well as a large "100" that does the same.

Under prior plans, the bill was supposed to enter circulation in February 2011, but "its introduction was postponed following an unexpected production delay," the Fed said in a statement.

The $100 note is the most frequently counterfeited denomination of U.S. currency outside the U.S., due to its broad circulation overseas.

The billions of older-design $100s already in circulation will remain legal tender after the new notes are released.

In recent years, U.S. officials have been trying to combat the continued production of extremely high-quality counterfeit $100 notes they say are produced in North Korea, dubbed the "supernote," which are undetectable to nearly all but the most sophisticated currency experts.

The Secret Service, the agency charged with policing the integrity of the nation's currency, maintains that only a tiny fraction of a percent of currency in circulation is counterfeit. But Secret Service officials have said they still encounter supernotes and other highly sophisticated fakes from overseas.

The new notes have been in development since 2003. The blue security ribbon is woven into the note's fabric—not printed on. Another security strip, visible to the left of Franklin's head when the note is held up to light, is embedded into the fabric. Like the old note, the new one has a watermark of Franklin's portrait, also visible when held up to light.

The old notes will be destroyed and replaced as they pass through the Fed system.

The dollar is the dominant currency used in international trade, and even serves as the primary currency in some countries. Officials have said as much as two-thirds of Federal Reserve notes in circulation are outside the U.S.

The Fed said officials will be "reaching out to businesses and consumers around the world" to educate them on how to identify the new bill.

For more information on the new design for the $100 bill, please see www.newmoney.gov.

By Pete Williams

The hospitalized Boston Marathon bombing suspect, Dzhokhar Tsarnaev, was charged Monday with using a weapon of mass destruction – and the White House said he will be tried in a civilian court.

“He will not be treated as an enemy combatant. We will prosecute this terrorist through our civilian system of justice,” White House Press Secretary Jay Carney said.

“Under U.S. law, United States citizens cannot be tried in military commissions. And it is important to remember that since 9/11 we have used the federal court system to convict and incarcerate hundreds of terrorists.”

Tsarnaev, 19, a naturalized U.S. citizen of Chechen origin, made his initial court appearance at Beth Israel Deaconess Medical  Center, where he was listed in serious condition.

He was advised of his rights and charged with one count of using and conspiring to use a weapon of mass destruction in the U.S. and one count of malicious destruction of property with an explosive device.

He was assigned three federal public defenders. The charges could carry the death penalty.

The suspect agreed to "voluntary detention," but declined to answer questions about bail, according to a court record. A probable cause hearing was set for May 30.

"Today's charges bring a successful end to a tragic week for the city of Boston and for our country," Attorney General Eric Holder said in a statement.

"We will hold those who are responsible for these heinous acts accountable to the fullest extent of the law."

A criminal complaint laid out some of the evidence against Tsarnaev, who was arrested Friday after a daylong manhunt, and his brother, Tamerlan, who was killed during a firefight with police.

A black jacket and white hat, matching the ones worn by "Suspect No. 2" in surveillance video, were found in the younger brother's dorm room, along with green strands of fuse like those used in the marathon explosives that killed three and wounded more than 170.

The video also captured the suspect making a cellphone call seconds before the first bomb exploded on the east end of Boylston St. during last Monday's race, and his utter calm in the face of spreading panic, the complaint said. The footage showed him hurrying away from his knapsack just 10 seconds before a blast erupted where he left it.

Tsarnaev was brought to the hospital with gunshot wounds to the head, neck, leg and hand. He had been communicating with investigators in writing because he couldn't speak, federal officials told NBC News. It's unclear what he told them.

The FBI has not revealed a motive for the attack last Monday that killed three people -- one of whom, Krystle Campbell, was laid to rest in Medford on Monday. Investigators are still probing whether the brothers received assistance from others, officials said.

7 biggest unanswered questions in Boston bombing

The feds have asked to speak with Tamerlan's wife, Katherine Russell Tsarnaev, who converted to Islam after she met her future husband at a nightclub. She dropped out of college, got married and had a baby three years ago.

Her lawyer, Amato DeLuca, told The Associated Press he was trying to work out the details of an interview.

His client, he said, worked up to 80 hours a week as a home health aide while Tamerlan watched their daughter. He said she didn't have any suspicions he might be plotting something.

He said she last saw her husband at home on Thursday morning, hours before he and his younger brother allegedly executed a campus police officer, pulled off the carjacking, and led police on a wild bomb-tossing chase that ended in a 200-bullet gun battle.

The carjacking victim told police his abductor asked if he'd heard of the marathon bombing and then said "I did that."

The man, who has asked that his identity not be revealed, told NBC News that he managed to escape and called his captors “brutal and cautious.”

Boston's top police official said Monday that while there are many unanswered questions, the city can rest easy.

"We're satisfied the two main actors, the people that were committing the damage out there, have been either captured or killed," Police Commissioner Ed Davis said on TODAY.

"There is still an open question as to exactly what happened in this investigation," he said. "We can't say with 100 percent certainty...anything, actually, at this point."

Among the mysteries Tsarnaev could solve is what his brother did when he traveled to Russia last year and who he met.

Rep. Mike Rogers, R-Mich., chairman of the House Intelligence Committee, said on “Meet the Press” that trip could be when Tamerlan "got that final radicalization to push him to commit acts of violence and where he may have received training."

FBI, Homeland Security and counterterrorism officials on Tuesday will provide a classified briefing to members of Congress on the Boston Marathon bombings.

Authorities are also trying to figure out where the suspects got their bomb-making supplies and guns. Cambridge Police said neither one had the necessary permits to carry firearms.

Immigration officials have arrested two of Tamerlan Tsarnaev's friends on immigration violations, days after they were detained and questioned by police in New Bedford, Mass.

In another development on Monday, the FBI turned the street where the bombings occurred – Boylston Street -- back over to the city of Boston, which will begin a cleanup and decontamination process before it is reopened to the public. A specific date has not been set.

As part of a handover ceremony, the FBI presented Mayor Thomas Menino with an American flag that flew at half-staff over the Boston Marathon finish line.