Colorado’s legislature approved one of the toughest renewable energy standards in the country on Monday.

Once the governor signs that legislation, utilities will be required to get 30 percent of their power from renewable sources by 2020. That follows an agreement Gov. Bill Ritter signed last week with Colorado’s largest utility, Xcel, and a coalition of energy companies and lawmakers to reduce pollution and shift several coal-fired power plants to natural gas by 2017.

The state’s clear move toward renewable energy — and away from coal — stands in stark contrast to some of its neighbors in the West, where the best and some of the worst of clean energy policies are on display.

If Hawaii's largest utility gets its way, the islands' abundant sunshine may be wasted.

In February, the Hawaiian Electric Company (HECO) proposed a ban on a booming industry of rooftop solar installations, claiming that too much distributed power generation could destabilize the islands’ isolated power grids. It was forced to back off by the public backlash, but environmental groups and the solar industry say the utility is trying other tactics that will stifle the growth of renewable energy in the state.

“Although HECO is backing away from doomsday for the local renewable industry at this point, all they did was defer the problem,” said Isaac Moriwake, an attorney for Earthjustice who is representing the Hawaii Solar Energy Association.

Biofuels are touted as a cleaner alternative to fossil fuels, but they come with their own set of problems. One of the biggest concerns lies in the displacement of food crops like corn, which can raise food prices and have other indirect effects around the world on land use and agriculture.

A new production method could begin to alleviate that problem while solving another: It turns trash into biofuel.

Environmental Protection Agency Administrator Lisa Jackson faced questions today from senators about her agency’s fiscal year 2011 budget request. Although representing only a small portion of the $10 billion total request, the ongoing battles regarding the EPA’s aim to regulate emissions of greenhouse gases from some sources took center stage.

The agency seems to be under attack from all angles when it comes to greenhouse gas regulation — House members seeking to overturn its authority to regulate greenhouse gases, senators calling for delays on regulation, states and industry groups attempting to sue. These maneuvers are drawing national attention and dividing Democrats in Congress. However, the chances of permanently preventing the EPA from regulating greenhouse gases appear slim.

There has been a lot of talk of next-generation reactors in the U.S. "nuclear revival," but some plans for new nuclear power generation are looking back rather than ahead.

Alongside a multitude of pending applications for new nuclear reactors, there is a move to restart construction at sites where the work began decades ago only to be abandoned before completion.

On Monday, the Nuclear Regulatory Commission held a hearing on challenges to the reinstatement of construction permits for one such project. It involves permits granted to the Tennessee Valley Authority to build the Bellefonte nuclear reactors, two reactors that were started near Hollywood, Ala., in 1974 but never finished.

After years of secrecy, Bloom Energy today finally unveiled the Bloom Energy Server, better known as the Bloom Box. It uses novel fuel cell technology to produce electricity from a combination of oxygen, heat and a fuel source like natural gas or biogas, and it is small enough to sit relatively inconspicuously on company property.

The device, already in use at eBay, Google and several other company campuses and distribution centers, has been hyped as a potential game-changer in the energy and power generation conversation. Whether or not it ever gets down to the anticipated price tag of around $3,000 and becomes viable on a residential scale, the Bloom Box raises questions of what type of energy future we should be planning for.

The dramatic potential for a meltdown and the dilemma posed by spent fuel tend to dominate discussions of nuclear power’s drawbacks, making it easy to forget the front end of that equation: uranium mining.

The United States imports the bulk of its nuclear fuel, but there are large deposits of uranium, mostly in the western part of the country, that could be mined. A new report from the U.S. Geological Survey looks at one such parcel of land in the Grand Canyon watershed area. It suggests that previous mining activity in the region has not resulted in serious contamination of soil or groundwater, but environmental groups and others are still trying to halt what they fear could become a huge upsurge in uranium mining activity.

On Capitol Hill, momentum appears to be shifting toward federal regulation of a drilling technique known as hydraulic fracturing. Last week, the head of the House Energy and Commerce Committee sent letters to eight oil and gas companies asking for information on the chemicals they use.

Oil and gas companies, including Exxon, have been vocal in their opposition to federal involvement, maintaining that the hodgepodge of state regulations is sufficient. In fact, Exxon is so opposed to federal regulation, it wrote into its recent $41 billion merger deal with XTO that if Congress makes “hydraulic fracturing or similar processes … illegal or commercially impracticable,” the deal is off.

Exxon CEO Rex Tillerson told a Congressional committee last month that the states have the knowledge of local geology to do the best job of regulation. However, a look at the state regulations now in place shows just how limited and inconsistent the oversight is of a practice that some people fear could contaminate water supplies.

Solar cycles of magnetic fields and sunspots have become a popular foothold for climate change skeptics. A new study in the journal Geophysical Research Letters, however, shows that even if predictions of an extended minimum of solar activity are accurate, it will have only a tiny effect on the Earth’s climate in comparison to the current track of human-caused warming.

“There is a lot of hysterical stuff out there,” said Gavin Schmidt, a climatologist at NASA’s Goddard Institute for Space Studies. “For some reason, solar effects seem to attract more than their fair share of cranks. There are always people with these statistical models claiming that it would have a big effect, but mostly that’s just nonsense.”

The new study, conducted by Georg Feulner and Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research in Germany, modeled what might happen to global temperatures if the sun enters a period of low magnetic and sunspot activity resembling that of the Maunder Minimum.

According to a new report commissioned by the National Association of Regulatory Utility Commissioners, maintaining all the current U.S. restrictions on oil and gas drilling through 2030 would cost the country $2.36 trillion in gross domestic product over the next 20 years.

This represents more than half a percent decrease in the economy every year for two decades, and drilling supporters are seizing on the numbers. However, some economists say the report ignores too many factors to be taken seriously.