Business Green: US utility Duke Energy has been forced to scale back its $100,000 plan for distributed solar energy generation on rooftops following negative reactions from the North Carolina Public Utilities Commission and local businesses including Wal-Mart. The utility, which announced plans in June to install $100,000 of solar panels on residential and commercial rooftops, has now proposed a scaled-down version of the plan, after concerns were raised about the cost of the proposals and the …