The green energy dream — why it may not happen.

As America looks to dramatically increase its use of renewable energy, an inconvenient reality stands in the way: the need to upgrade the country's antiquated electricity grid. Part of that overhaul involves the construction of gigantic and expensive long-distance transmission lines to carry clean energy from remote sites to population centers. NOW travels to California, which has the most ambitious clean energy plan in the nation, but the state's efforts face stiff opposition from property owners and conservationists who prefer renewable energy from "local sources," such as photovoltaic rooftop solar panels. Complicating the matter are claims that the transmission lines are not actually carrying renewable energy at all, but represent a thinly-disguised strategy to stick to old energy practices.

NOW's Web site (www.pbs.org/now ) will provide clickable state-by-state information on initiatives to provide clean energy and encourage energy efficiency.