The Electric Grid Today and Tomorrow
Electric Grid Architecture Today
The United States economy, security and its citizens are highly dependent on a reliable and resilient electric system with growing expectations and interactions by customers. Customers are growing less tolerant of outages of tens or hundreds of minutes per year on average with voltage fluctuations that interrupt a customer’s digital world. Customers also are resisting paying a growing percentage of household expenses for their electricity use.
The transformation of the architecture of the grid began in the 20th century from isolated networks recognizing the economies of scale of interconnection to share resources and the diversity of demand. Electricity prices dropped with technology and interconnection. Then demand slowed and prices rose. Demand-side management, PURPA (1978), deregulation and market development attempted to stem the tide of rising prices. Investment in the transmission and distribution grid slowed due to lower demand growth (and efficiencies) and the confusion (from an investor’s standpoint) in the transmission space with the advent of independent system operators (ISOs) and regional transmission operators (RTOs).
Deregulation created a horizontal unbundling of the grid in some portions of the country separating electricity supply from end use interconnected by transmission and distribution (wires). Retail providers emerged to create aggregation vehicles to help customers interact with the marketplace. Other portions of the country remain in a vertically integrated paradigm from supply to end use. Price in some portions of the country has been a primary driver of deregulation, with lower price areas of the country remaining status quo to preserve their price position.
Environmental regulations, renewable penetrations and the advent of shale gas have created the perfect storm for the electric grid. Fuel transformation in the United States has only begun creating the changes to the grid that are needed to ensure our nation’s electricity future.
Investments in the transmission grid have increased substantially soon after the Energy Policy Act of 2005 and FERC’s actions in response, coupled with more robust regional planning. The blackout of 2003 in the Northeast, the precursor of EPAct2005, was a rude awakening to the need to improve reliability with mandatory standards. Investments have essentially doubled per annum in transmission from the 1990s and early 2000s. Recent transmission investments have spiked to address the fuel transformation that is occurring in the United States.
The transmission grid has enjoyed technology enhancements, including the proliferation of phasor measurement units that track grid operation in millisecond fashion rather than the previous paradigm of every few seconds. Power electronics advancements have enabled newer HVDC technology (using voltage source converters) for better applications for underground and undersea development. Composites have enabled advance conductor to carry greater power flows over the same rights-of-way with greater efficiency. Other monitoring devices have created dynamic ratings of transmission and corridors for better performance.