Power Generation, Transmission, and Use

Markets, Regulation, and Oversight

Impacts of Power Generation and Transmission

Looking Ahead


CEIR Report Map


Maryland Power Plants and the Environment (CEIR-18)

2.3 Electric Transmission

The network of high-voltage lines, transformers, and other equipment that connect power generating facilities to distribution systems are part of an expansive electric transmission system. In Maryland, there are more than 2,000 miles of transmission lines operating at voltages between 115 kV and 500 kV. Figure 2-14 shows a map of this high-voltage transmission grid in Maryland.

Figure 2-14 Transmission Lines in Maryland (>115 kV)

Figure 2-14

While the economic and environmental effects of generation are substantial, transmission also has major environmental and socioeconomic implications in Maryland, particularly since Maryland is a net importer of electricity. Building new transmission facilities is costly with significant environmental impacts and ratepayer costs. Upgrading existing heavily used facilities must be done quickly, often in short windows of time, while minimizing environmental impacts. Shortages of transmission capacity or congestion can lead to higher priced out-of-merit generation dispatch and extremely high energy and capacity prices over peak time periods.

PJM has operational control over and planning responsibility for most of the high-voltage transmission facilities in Maryland.  As part of its transmission planning responsibilities, PJM routinely examines projections of generation, transmission and loads to determine if additional transmission facilities are needed to comply with applicable transmission planning standards and associated reliability criteria.  PJM also periodically examines whether certain new transmission lines will produce economic benefits even if they are not needed for reliability reasons.  To the extent PJM determines a need for a transmission project and includes it in the Regional Transmission Expansion Plan (RTEP), there is an expectation that the transmission owner will file for a CPCN seeking permission to construct the proposed transmission line.

Most recently, PJM participated in the DOE-funded interconnection-wide plans as part of the 2009 economic stimulus effort. Planners selected three scenarios and analyzed the transmission systems of each in the year 2030. The Eastern Interconnection Planning Collaborative submitted its plan to the U. S. Department of Energy in late April 2013 that included estimates of transmission operations and maintenance in 2030, along with the cost to build new facilities that may be required to meet the multi-policy future. This plan is detailed in Section 3.3.