This interactive diagram from the National Academy of Sciences shows how we rely on a variety of primary energy sources (solar, nuclear, hydro, wind, geothermal, natural gas, coal, biomass, oil) to supply energy to four end-use sectors (residential, commercial, industrial, and transportation). It also focuses on lost or degraded energy.

This short video shows how different biomass feedstocks are processed and refined into sustainable biofuels via biochemical and thermochemical processes.

In this video, students explore the work of Jay Keasling, a biologist who is experimenting with ways to produce a cleaner-burning fuel from biological matter using genetically modified microorganisms.

This is a series of 10 short videos, hosted by the National Science Foundation, each featuring scientists, research, and green technologies. The overall goal of this series is to encourage people to ask questions and look beyond fossil fuels for innovative solutions to our ever-growing energy needs.

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.

This Flash animation describes how hybrid-electric vehicles (HEVs) combine the benefits of gasoline engines and electric motors and can be configured to obtain different objectives, such as improved fuel economy, increased power, or additional auxiliary power for electronic devices and power tools.

This video is from the Energy 101 video series. It explains the process for converting micro-algae into fuel and makes the case that algae-based biofuels hold enormous potential for helping reduce our dependence on imported oil.

This video reviews the benefits and drawbacks associated with growing corn to make ethanol.

In this interactive, students can investigate a typical hydrogen fuel cell prototype car from its fuel cell stacks to its ultracapacitor, a kind of supplementary power source.

The limited-production vehicle seen in this feature is a Honda 2005 FCX, which is typical of the kinds of hydrogen fuel cell cars that some major automakers are researching and developing.

This video segment is adapted from Building Big, a PBS series hosted by David Macaulay. It explores Hoover Dam's hydroelectric capabilities by explaining how it is able to harness the potential energy stored in the reservoir and convert it to electricity. It also discusses environmental impacts of the dam and others like it.