By year’s end, regulators are expected to approve a host of solar energy projects in California that could eventually produce as much electricity as several nuclear plants. In an interview with Yale Environment 360, John Woolard, the CEO of the company that has begun construction on the world’s largest solar-thermal project, discusses the promise — and challenges — of this green energy boom.

Climate policies that require public sacrifice and limiting economic growth are doomed to failure. To succeed, policies to reduce emissions must promise real benefits and must help make clean energy cheaper.

Will electric cars one day become part of a network of rechargeable batteries that can help smooth out the intermittent nature of wind and solar power? Many experts believe so, pointing to programs in Europe and the U.S. that demonstrate the promise of vehicle-to-grid technology.

The U.S. has invested billions of dollars trying to create a controlled form of nuclear fusion that could be the energy source for an endless supply of electricity. But as a federal laboratory prepares for a key test, major questions remain about pulling off this long-dreamed-of technological feat.

How significant would it be if America’s 29 million small businesses increased their energy efficiency and reduced their emissions? Judging from the example of one California entrepreneur, the impact could be far greater than you might expect.

Europe is in the midst of a wind energy boom, with the continent now installing more wind power capacity than any other form of energy. In an interview with Yale Environment 360, the European Wind Energy Association's Christian Kjaer describes his vision of how wind can lead the way in making Europe’s electricity generation 100 percent renewable by 2050.

An activist caravan to bring one of Jimmy Carter’s solar panels back to the White House symbolizes the time that the U.S. has lost in developing new energy technologies ”“ and the urgent need for taking action on climate.

Consumers now have little information about the true ecological impacts of what they buy. But that may be about to change, as new technologies that track supply chains are emerging and companies as diverse as Unilever and Google look to make their products more sustainable.

New technologies, feed-in tariffs, and tax credits are helping propel the small wind industry, especially in the United States. Once found mostly in rural areas, small wind installations are now starting to pop up on urban rooftops.

Many energy experts contend natural gas is the ideal fuel as the world makes the transition to renewable energy. But since much of that gas will come from underground shale, potentially at high environmental cost, it would be far better to skip the natural gas phase and move straight to massive deployment of solar and wind power.

Even after the failure to reach agreement on binding CO2 cuts in Copenhagen last December, the United Nations’ outgoing chief climate negotiator is confident that the world is making progress on global warming. The key, he says, is convincing all nations, particularly developing ones, that tackling climate change is in their long-term economic interest.

As utilities seek to build new nuclear power plants in the U.S. and around the world, the latest generation of reactors feature improvements over older technologies. But even as attention focuses on nuclear as an alternative to fossil fuels, questions remain about whether the newer reactors are sufficiently foolproof to be adopted on a large scale.

As global warming intensifies, demands for human manipulation of the climate system are likely to grow. But carrying out geoengineering plans could prove daunting, as conflicts erupt over the unintended regional consequences of climate intervention and over who is entitled to deploy climate-altering technologies.

Environmentalist David Orr says the easy part of helping the United States live within its ecological limits may be passing laws, such as one that puts a price on carbon. The hard part, he maintains in an interview with Yale Environment 360, is changing a culture of consumption that causes extensive environmental damage — and unhappiness.

Flying dwarfs any other individual activity in terms of carbon emissions, yet more and more people are traveling by air. With no quick technological fix on the horizon, what alternatives — from high-speed trains to advanced videoconferencing — can cut back the amount we fly?

The practice of “commissioning,” in which an engineer monitors the efficiency of a building from its design through its initial operation, just may be the most effective strategy for reducing long-term energy usage, costs, and greenhouse gas emissions from buildings. So why is it so seldom used?

California’s high-tech giants have long used renewable energy to help power their Silicon Valley headquarters. Now, companies such as Google, Adobe Systems, and eBay are preparing for the next step — investing in off-site solar and wind installations and innovative technologies that will supply their offices and data centers with green electricity.

Despite strong evidence that growing food crops to produce ethanol is harmful to the environment and the world’s poor, the Obama administration is backing subsidies and programs that will ensure that half of the U.S.’s corn crop will soon go to biofuel production. It’s time to recognize that biofuels are anything but green.

After making his fortune with Idealab and a host of technology start-ups, Bill Gross has turned his attention to renewable energy. In an interview with Yale Environment 360, Gross talks about the solar power plant technology his company eSolar is developing and about the future of solar.

The drive to extract and store CO2 from coal-fired power plants is gaining momentum, with the Obama administration backing the technology and the world’s first capture and sequestration project now operating in the U.S. Two questions loom: Will carbon capture and storage be affordable? And will it be safe?

There has been growing talk about a clean-tech race between China and the U.S., often cast in ominous tones. But the quest to develop and implement renewable energy can be one where both nations win.