Well, let's just do a little more detailing on your points.
1. In terms of Obama's position on both nuclear and coal energy, he voted to guarantee loans to numerous alternative energy companies nuclear and "gasified coal" were just two and included loans for hydrogen cell cars, wind and solar energy, etc.

2. Obama donated to Ned Lamont's campaign after he won the nomination, but yes, he did ultimately support Lieberman. But his PAC also supported EVERY democratic candidate to help them maintain their seats.

Oh, and before we move on to Obama's support from corn farmers, lets note that the Senator is supporting cellulosic ethanol, a significantly more energy-efficient conversion system

"Lugar and Obama introduced the American Fuels Act, S. 2446, which would take a four-step approach to reducing America’s dependence on foreign oil. First, the legislation would spur investment in alternative fuels by increasing the production of cellulosic biomass ethanol and create an Alternative Diesel Standard. Second, it would help increase consumer demand for alternative fuels by providing a short-term, 35 cents per gallon tax credit for E85 fuel and by providing automakers with a $100 tax credit for every FFV produced. Third, it would require the U.S. government to increase access to alternative fuels by requiring the government to allow public access to alternative fueling stations located on federal government property. Finally, it would create a Director of Energy Security to oversee and keep America focused on its goal of energy independence." February 2006: Senator Lugar's Energy Legislation