This was supposed to be a big year for energy-related technology.

It was supposed to mark the ascendance of the electric car as the first full year of sales for GM's Volt and Nissan's Leaf, which represent the leading edge of electric vehicles planned by major automakers. But GM fell far short of its sales goals for the year, no doubt plagued by high costs due to expensive batteries. And the company ended the year under a cloud of smoke as the Volt's battery pack caught on fire after safety testing.

It was the year by which advanced-biofuels companies were supposed to be producing 250 million gallons of fuels from grass and wood chips to meet a U.S. federal mandate. But the EPA had to waive the mandate, decreasing the goal to just 6.6 million gallons, because no large advanced-biofuels plants were up and running. The year ended with the demise of one of the first advanced-biofuels companies, Range Fuels, which shut down operations and was forced to auction off assets.

By 2011, advanced solar cells based on thin films of the semiconductor copper indium gallium selenide were supposed to be manufactured at high volumes. The cells were to be nearly as efficient as conventional silicon solar cells but much cheaper to produce, making solar power much more affordable. But Solyndra, a Silicon Valley-based company with one of the most innovative CIGS solar-cell designs, collapsed as it struggled to bring down manufacturing costs. Its bankruptcy in September led it to shut its factory in Fremont, California, which had been funded with the help of a $535 million federal loan guarantee. The failure dominated public attention on the subject of alternative energy and prompted congressional investigations.

In recent years, the nuclear industry had seemed to be set for a renaissance: dozens of applications for new plants were filed, and the government offered millions in loan guarantees to support construction. Not only did the renaissance in U.S. plant construction fail to materialize in 2011, but the horrific disaster at the plant in Fukushima, Japan, set the industry back even further.

And once again, Congress failed to pass a comprehensive energy policy.

But there is also good news.

Although thin-film CIGS solar cells haven't revolutionized the solar industry, advances in manufacturing and sheer scale have led to huge drops in the price of conventional silicon solar panels, making solar power more affordable. In 2011, average prices for solar panels dropped by almost 50 percent from 2010 levels, according to an estimate from GTM Research. Just three years ago, solar panels costs more than three times what they do now. Innovations introduced this year could lead to even lower prices. One technology, developed first at BP Solar but commercialized first in China, could cut the cost of making high-quality crystalline silicon in half. Other advances, such as Suntech's Pluto technology, which combines a number of innovations to produce a record-efficiency solar cell, and silicon ink from Innovalight, which increases power output by improving electrical connections, are being ramped up for large-scale production, promising to keep reducing the cost per watt of solar power.