Advanced Energy Perspectives

Water heating technology spans a range of options, from conventional technologies to renewable systems. Conventional storage water heaters typically use natural gas or electricity to keep water hot in an insulated tank, ready for use at any time. They have a simple design and are relatively inexpensive, but they also have standby losses associated with storing hot water for long periods of time. High-efficiency models increase heat transfer efficiency and reduce standby losses with more insulation.

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

Superconductivity is a property of certain materials whereby electrical resistance, which normally decreases gradually with decreasing temperature, suddenly drops to zero at a critical temperature, allowing greater current to flow and eliminating resistive losses. Advances in material science have created high-temperature superconductors (HTS), with relatively “warm” critical temperatures of -315°F to -230°F that allow for the use of less expensive and easier to handle coolants such as liquid nitrogen. HTS systems transmit electricity through a superconducting cable that is insulated with liquid nitrogen pumped by refrigeration equipment. This allows HTS cables to carry 10 times the power of a standard cable of similar thickness with almost no losses. These lines can connect directly to the existing AC transmission system to add highly efficient transmission capacity that can relieve congestion without the need for high voltages.

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.