TechPulse 360

Energy Secretary Steven Chu is the first to admit the nation faces a clean-energy technology gap.

"We don't have all the technolgy we need to reduce carbon by 80 percent by mid century," says Energy Secretary Steven Chu

“We don’t have all the technology we need to reduce carbon by 80 percent by mid century,” Chu said Monday. “We need better technology.”

Advancing the state of green tech is the reason he invested $80 billion of Recovery Act funds in clean-tech research, product development and generating capacity. The nation needs to prepare itself for the green economy of the 21st Century at a time when countries, such as China, are pouring in lots of money of their own.

We are falling behind in the clean-tech race,” he said during an address at Stanford University.

And yet, all is not bad news. During his address, Chu listed several technologies where the U.S. is making progress and which could have a powerful impact in the decades to come. They include:

*Utility-scale energy storage,  an important addition to the energy grid as more renewable power comes from sometimes on, sometimes off wind and solar. The best way to achieve store energy is by pumping water up a hill, says Chu. When the power is needed, water is released, driving turbines. The energy loss: just 25 percent, far better than batteries, he says.

*Offshore wind has a great deal of untapped potential, adds Chu. But maintaining turbines is difficult in a marine environment due to storms and salt water.

One encouraging step is Clipper Windpower’s work on a massive 10 MW offshore wind turbine, says Chu.

*In the solar market, the cost of solar cells has dropped by a factor of 10. But it isn’t low enough for panels to be competitive without government subsidies. That could rapidly change, says Chu. Module costs are about $2 a watt, but will drop to less than $1 by the end of the year.

The drop will help rooftop solar compete. Rooftop systems still cost $4 a watt to install, with the panels accounting for half of the bill. At $1.50 cents installed, solar becomes cost efficient without subsidies, he says.

Chu says it is not clear whether low cost thin-film cells will outsell the polysilicon cells that make up the majority of today’s market. Polysilicon cells keep making gains with efficiency.

*The transportation sector is the toughest to achieve energy improvements. Lithium ion batteries don’t have near the energy density of gasoline or diesel. Fortunately, electric motors are highly efficient.

One breath of fresh air may come from aluminum batteries, says Chu. Aluminum could help cut battery costs by a factor of 10. Suddenly all the energy required by a building could be stored in a battery the size of a room.