The U.S. Energy Information Administration (EIA) has commissioned a new study that examines the role of high-voltage direct current (HVDC) lines in integrating renewable energy resources into the electric grid.
The conclusion? According to the agency, its review indicates that although applications in the current electric transmission network are limited, HVDC lines have a number of potential benefits: cost-effectiveness, lower electricity losses, and the ability to handle overloads and prevent cascading failures.
The conclusion? According to the agency, its review indicates that although applications in the current electric transmission network are limited, HVDC lines have a number of potential benefits: cost-effectiveness, lower electricity losses, and the ability to handle overloads and prevent cascading failures.
In turn, these attributes mean that HVDC lines could, if properly configured, help mitigate some operational issues associated with renewable generation, according to EIA.
The agency explains that renewable resources can be categorized into two types of generating sources: dispatchable and non-dispatchable. Dispatchable generators can respond to real-time system operator instructions to increase or decrease output. Among renewable power plants, those fueled by geothermal and biomass resources are considered dispatchable.
Non-dispatchable renewables, such as those fueled by solar and wind energy, are dependent on the availability of naturally occurring resources. As a result, according to EIA, these technologies can have a limited capability to respond to dispatch signals. On the other hand, hydroelectric generators fall between these categories; they can typically respond to dispatch signals, but they often have seasonal operational limitations that prevent them from being completely dispatchable.
The agency says the increasing deployment and penetration of non-dispatchable renewable resources – solar and wind, for example – can lead to operational issues, such as under- or over-production of electricity during the times of high or low system demand. These fluctuations may increase the need for additional grid services to keep electricity supply and demand balanced. In addition, some renewable resources, especially wind, can be geographically constrained, with the best resources located far from areas of high electricity demand, according to the agency
