• Biden Urges Investment in Clean Energy: Saying a failure to invest in clean energy technologies would be "the biggest mistake this nation has made in its history," Vice President Joe Biden called on politicians and entrepreneurs at the National Clean Energy Summit yesterday to step up their innovation in clean technologies. He also said that the federal investment in cleantech companies has spurred economic growth: Five firms that got big government seed money have since landed a total of $100 million in private investments.

• Energy Secretary Chu on How the Government Can Keep Helping: Also at the Summit, Steven Chu spelled out three ways that the government can keep the momentum going: Investing in research in energy and education, enacting a clean energy standard for speeding renewable energy projects, and creating a Clean Energy development agency.

• What to Do with End-of-Life EV Batteries? As EVs continue to percolate into the public consciousness, and onto the world's roads, the problem of what to do with EV and hybrid batteries at the end of their lives is becoming a big concern. The Times takes a look at how the major auto manufacturers are dealing with EV and hybrid batteries, and why legislation is going to have to be the key driver for recycling for now: Recycling lithium for reuse currently costs five times as much as mining new lithium for batteries.

• Giving 'Dirty Fuel' a Green Spin: Speaking of alternative fuels, Environmental Protection is reporting on one of the results of the decade-old National Fuel Cell Research Center in California: Fuel from sewage. Researchers at UC Irvine have created a unique fuel cell generator that simultaneously converts gas created in wastewater digesters to hydrogen used for a zero-emission vehicle fuel -- and at the same time creates electricity and heat for non-vehicle uses.

• The High Costs of Cleaning Dirty Water: Speaking of wastewater, a study out of Cincinnati finds that wastewater recycling plants release three times the emissions of traditional water treatment plants. Despite the much higher levels of nitrous oxide emissions, the researchers say that wastewater recycling can have big environmental benefits, especially if the reclaimed water is used for drinking water and other non-irrigation purposes.

• First Sub-$15 LED Lightbulb to Hit he Market: LEDs, it is widely agreed, are the next big thing for energy-efficient lighting. They face two big problems in getting to market at any big scale: Getting light quality up to par with incandescents or even CFLs, and bringing the cost down -- most LEDs cost more than $20 per light, with some up in the $40 range. The Lighting Science Group this week announced that it's created a 60-watt-equivalent LED bulb that will retail for less than $15, aimed at the booming Indian market for lighting.