…The regional cap-and-trade program is regarded as a success because it has demonstrated that a price can be established for carbon without crippling the economy or driving electricity prices sky-high. Since 2008, when RGGI was launched, electricity prices across the nine states have fallen an average of 8 percent and the state economies have grown faster than the nation as a whole, according to Acadia Center, a clean energy advocacy group. A total of 28 carbon allowance auctions have been held since September 2008, generating more than $2 billion in revenue for the participating states. Massachusetts’s share of the total is $345 million…