This animated slideshow introduces biodiesel as a fuel alternative. With concern about the use of petroleum-based fuels at an all-time high, biodiesel is experiencing a popularity surge. And algaeâotherwise known to some as pond scumâ are grabbing headlines as the next potential biodiesel superstar. But how and why do algae make oil? And why do they make so much of it? In this audio slide show, U.C. Berkeley's Kris Niyogi describes the process and its potential.

This video is one of a series from the Switch Energy project. It reviews the environmental impacts of various energy resources including fossil fuels, nuclear, and renewables. CO2 emissions as a specific environmental impact are discussed.

This series of informative graphics provide a regional overview of US energy resources.

This video addresses the importance of efficiency in providing power to an increasingly large global population.

In this video segment from NOVA's Saved By the Sun hour-long video, students learn about photovoltaics and see how two families are using solar technologies in their homes. The video introduces the ideas of state incentives and net metering benefits.

Students investigate passive solar building design with a focus on heating. Insulation, window placement, thermal mass, surface colors, and site orientation are addressed in the background materials and design preparation. Students test their projects for thermal gains and losses during a simulated day and night then compare designs with other teams for suggestions for improvements.

This video is one of a series of videos from the Switch Energy project. It describes three types of geothermal sources -- rare ones in which high temperatures are naturally concentrated near the surface, deep wells that require fracturing the rock and then circulating water to bring heat to the surface, and low temperature sources that use constant temperatures just below the surface to heat or cool a building. The latter two are more widely available but cost-prohibitive today.

In this activity, students explore the basic living requirements of algae (phytoplankton)through hands-on experience and an interactive game. Students investigate what algal biofuels are, how they are made, where they can grow, and, most importantly, why this topic should be investigated. Algal biofuels are an emerging source of renewable energy.

In this activity, students use Google Earth to investigate ideal features of wind farms.

This video segment from 'What's Up in the Environment,' shares how an entire home can be constructed using green energy sources (solar and geothermal energy). Video is narrated by young boy whose father is the chief engineer on the project.