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. 

Hydroelectric power plants use turbines and generators to convert the kinetic energy of moving water into electricity. There are three major types of hydroelectric power plants: impoundment, run-of-river (diversion), and pumped storage. An impoundment facility uses a dam to store river water in a reservoir, which it then releases through turbines to generate electricity. The height differential (“hydraulic head”) between the reservoir surface and the turbine outlet is what provides the energy for power generation. A run-of-river facility takes advantage of natural elevation changes along a river, diverting a portion of the river flow via pipes or underground conduits to drive turbines and generate power without a dam. Because of this design, the output from run-of-river plants can uctuate throughout the year, whereas impoundment plants generally have steadier output. Pumped hydro storage is a form of bulk energy storage that generates electricity when demand is high. In addition to these three major variants, there is a niche application called in-conduit hydropower, which uses hydro turbines to harness energy from water supply infrastructure such as tunnels, irrigation canals, and pipes.

A Building Energy Management System (BEMS) is an integrated system of software, hardware, and services that monitors, automates, and controls energy use through information and communication technology. Used primarily in commercial and industrial buildings, BEMS technology increases building ef efficiency and comfort by controlling building systems such as heating, cooling, and lighting. Institution-wide energy management systems, often called enterprise energy management systems (EEMS), are being deployed by universities, governments, and retail chains. BEMS can also be combined with software-based data analytics to provide more information and control, particularly across multiple properties.

Image courtesy of Ormat.

Waste Energy Recovery (WER) describes any process in which energy that would typically be “thrown away” is captured and put to use. In broad terms, there are three types of waste energy sources suitable for recovery: waste heat, excess pressure in steam and other industrial processes that is normally dissipated, and residual fuel value in industrial process streams (purge gases, off-gases, etc.). WER can be used to generate electricity or to produce thermal energy for industrial processes. Some applications of WER are similar to combined heat and power (CHP), except that instead of the fuel used by CHP systems, WER uses recovered energy that is otherwise considered waste.

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.