Viable alternative energy solutions are still a long ways off. Batteries in hybrid vehicles have a severe environmental impact from the mining process for raw material, to international transit of materials to various processing facilities, and finally to disposal. Pure electric cars that require a plug-in still gets its energy off the power gride which often comprises of plants burning fossil fuels to provide said energy. Solar energy is nothing more than supplemental energy to a more viable main source. Wind farms have proven to be hugely inefficient as well as having a myriad of negative environmental impacts, from killing tens of thousands of birds to taking up precious, farmable land.
The personal automobile is disastrously inefficient in any form. The average vehicle weighs over four thousand pounds here in N.A, and transports not even a tenth of its weight. Throw in the massive infrastructure required for it(roads, materials, fuels, lubricants, businesses, regulations, etc) and you have huge amounts of material that, frankly, very few if any truly need.
The Prius, Nissan Leaf, and Chevy Volt crowds are no more saintly or environmentally concious than those that drive Camaros and SUVs. There is no "saving" the environment here, but merely a slick marketing campaign that has hugely succeeded in pushing these "Green" vehicles to the masses. These "green" vehicles also do not possess the powerplants necessary to power heavy vehicles within the trucking, construction, aeronautical and military industries.
Loans being paid back in advance aside, our government has absolutely no business in gambling with taxpayer money on a company whose business is selling six-figure luxury sports cars geared towards a tiny segment of the car-buying public. The administration got very lucky, as the Tesla experiment could have very easily slid into bankruptcy.