As both wind and solar generation grow, high-voltage transmission networks must grow as well—both to carry green electrons to load centers and to allow grid operators more flexibility. “Retiring coal and nuclear units will also drive new investment in transmission,” said E & E’s transmission sector lead Dan Belin.

Current investment trends in transmission favor smaller, intra-state projects, according to Belin. “Projects focused on one state or, at the most, within one regional market such as the MISO, PJM or SPP are getting the most traction,” he said. “Building transmission within one organized market, you’re a lot more likely to get agreement on cost allocation and cost recovery to build the project,” he added “FERC, with its order 1000, is encouraging inter-regional development between and among markets, but that hasn’t come to fruition yet as a trend.”

The trend toward shorter transmission lines holds true for high-voltage direct current projects as well. “We are seeing more shorter HVDC lines proposed,” said Cheryl Karpowicz, E & E’s senior vice president of development, noting that HVDC lines can be buried “to avoid visual impacts and to transform electrical systems into more resilient networks.”

Also more common are reconductoring and transmission system upgrades, while new-build projects are less common. “There will be situations such as where a nuclear or coal plant is retired, but the line connecting to its substation will be upgraded from 230 kV to 345 kV to accommodate some new wind generation,” said Belin.

These types of projects generally present less of an environmental permitting challenge, while new transmission lines—even the shorter, lower capacity ones—can be difficult to permit given the potential impacts on sensitive species, existing land uses and cherished viewsheds. "A prime example of this trend is the now famous Tehachapi transmission project in California, built to access wind resources," said Belin. "On that project, the developing utility was required to bury the line through populated areas after they had constructed their towers. Less than five miles needed to be buried, but the public opposition that drove the decision dramatically increased project cost and time spent in legal challenges. It took six years to resolve that issue. We expect these trends to continue and advise clients to place a priority on stakeholder outreach and public involvement."

Interested in learning more about how these trends might impact your project?

© Ecology and Environment, Inc.    All Rights Reserved

© Ecology and Environment, Inc.    All Rights Reserved

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