Advanced Energy Perspectives

This post is one in a series featuring the complete slate of advanced energy technologies outlined in the report This Is Advanced Energy. 

Photo courtesy of Ocean Power Technologies.

Marine and hydrokinetic power technologies generate electricity from the kinetic energy of moving water, including waves, currents, and tides. Wave energy devices are designed to capture energy from the rising and falling of waves or their forward movement. For example, the relative motion between a buoy at the surface and a fixed tether on the sea floor can be used to drive a generator. Tidal energy can be captured in two ways. First, in places with the right undersea topography, daily currents created by ocean tides can be used to drive underwater turbines. Similar technology can exploit the constant ow of water in rivers or in large-scale ocean currents like the Gulf Stream. Second, in places with large tidal ranges, tidal barrages (dams or barriers) can be built across bays or estuaries to capture energy from the receding tide via turbines as water ows out to sea. Within each category, there are many different technologies in development, particularly for wave energy capture. Proximity to shore, ocean depth, and expected sea conditions are all major considerations for these technologies. Another type of marine energy, called Ocean Thermal Energy Conversion (OTEC), exploits temperature and/or salinity gradients between surface waters and deeper water to drive various power cycles.

This post is one in a series featuring the complete slate of advanced energy technologies outlined in the report This Is Advanced Energy. 

Photo courtesy of Clean Energy Fuels. 

Compressed Natural Gas (CNG) and Liquefied Natural Gas (LNG) are gaining market share as transportation fuels. The technologies for producing, storing and using both CNG and LNG are well developed. With CNG, pipeline natural gas is compressed to 3,000 to 4,000 pounds per square inch (psi) and stored in a pressurized tank on board the vehicle. CNG fueling stations include all the equipment necessary to take natural gas from the local distribution system, compress it, and refuel the vehicles. With LNG, the natural gas must be cooled to about -260°F at which point the methane (the main constituent of natural gas) turns to a liquid. The LNG is stored in insulated cryogenic tanks at the refueling station and on board the vehicle.

This post is one in a series featuring the complete slate of advanced energy technologies outlined in the report This Is Advanced Energy. 

As the dominant technology for passenger vehicles for over 100 years, gasoline-powered internal combustion engine (ICE) vehicles continue to improve their fuel efficiency and performance in dramatic ways. In addition to general improvements to reduce vehicle weight and improve drivetrain efficiency, several engine innovations are at various stages of development and commercial deployment. Three of these innovations are covered here: low-temperature combustion (LTC), lean burn gasoline combustion, and direct fuel injection.