Advanced Energy Perspectives

Image courtesy of Ford Motor Company.

Hybrid electric vehicles (HEVs), commonly called “hybrids,” are powered by a combination of a conventional internal combustion engine (typically gasoline-fueled) and a battery-powered electric motor, usually featuring a nickel-metal hydride or lithium-ion battery. The hybrid drivetrain works in several ways to improve fuel economy. Having a larger battery than a conventional vehicle allows the engine to turn off at low speeds, when driving downhill, and while idling. Since the electric motor can assist with acceleration, a smaller gasoline engine is used, which reduces fuel consumption. The integrated system also allows the gasoline engine to operate in a more efficient power range.

Combined Heat and Power (CHP), also known as cogeneration, produces electricity and useful heat from the same fuel source in an integrated system. CHP systems recover exhaust or waste heat from electricity generation for use in industrial processes, space heating, and water heating. CHP technology achieves greater levels of overall efficiency than using separate thermal and power systems. Any fuel type can be used, including fossil fuels and renewable fuels. Because thermal energy (steam, hot water) is more difficult to transport than electricity, CHP systems are typically installed at sites with large, steady thermal loads, such as industrial facilities, college campuses, hospitals, and military bases. CHP systems can also power district energy plants, which produce steam, hot water, and/or chilled water at central plants, then distribute the steam or water to multiple buildings through a network of insulated pipes generally located underground.

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

Offshore wind off the coast of England. Via.

Offshore wind turbines are very similar in design to land-based large-scale turbines. They are located in bodies of water where there is access to stronger, steadier wind resources than are typically available on land. Generally, the turbines are fixed directly to the bottom of a lake or ocean, although technologies are being developed to mount turbines on floating platforms, which will enable deployment in deeper water or farther offshore. Because of the higher expense of foundations and installation compared to land-based wind turbines, offshore wind farms generally feature larger turbines to minimize infra- structure requirements. Offshore wind turbines are typically 3-5 MW in size, but Vestas has installed 8 MW turbines, and even bigger turbines (10-15 MW) are under development.

Small modular reactors (SMRs) are small-footprint nuclear power plants that can be sized between 10 MW and 300 MW. There are numerous SMR plant designs, although SMRs all rely on the same nuclear fission technology used by larger plants. Nuclear fission releases heat in the reactor core that is used to produce steam, which spins a steam turbine attached to an electric generator. Unlike utility-scale plants, which are difficult to site and can take years to construct, SMRs are designed to have many components fabricated and assembled offsite, thus reducing the time and complexity of plant construction and increasing potential plant locations. SMR designs generally have their reactors buried in the ground away from weather hazards, and are often designed to use passive cooling systems that are not vulnerable to power outages, further increasing the safety of the plant.