ISO New England announced Wednesday that prices are now at their lowest levels since 2003.
The ISO says prices dropped from $46.23 per megawatt hour in 2011 to $36.09 last year. That means consumers paid $1.5 billion less for electricity in 2012 - from $6.7 billion in 2011 to about $5.2 billion in 2012.
The ISO says the drop is partly driven by a 20 percent price decrease for natural gas, New England's dominant fuel for energy production.
The ISO says lower demand - due in part to the economic downturn, milder weather and better energy efficiency - has also pushed prices down.