Dive Brief:

• A December study by researchers from the Massachusetts Institute of Technology concludes the United States can fully decarbonize its power sector through the use of existing technologies — and that tackling decarbonization through a federal policy framework, rather than individual states setting clean energy goals, can help to significantly lower the costs.
• The research found that interstate coordination and an expansion of the nation's transmission system could lower the cost of fully decarbonizing the electrical grid by 2040 by 46%, relative to an approach where states pursue individual goals.
• A separate study sponsored by Americans for a Clean Energy Grid (ACEG), a coalition of energy companies and renewables groups, concluded that a comprehensive approach to building transmission lines to serve Eastern load centers could could save consumers $100 billion on electric bills by 2050.

Dive Insight:

A comprehensive approach to transmission planning and expansion could save consumers billions and help bring more renewable energy to the electric grid, the two reports make clear.

According to the MIT paper, a full decarbonization of the United States' power sector does not hinge on new breakthroughs and emerging technologies, but instead can be accomplished with a full embrace of resources that already exist and are widely used today, including solar, wind, lithium-ion batteries and transmission capacity. 

The most immediate needs include new wind and solar resources, and expanded transmission capacity. While the study includes the use of lithium-ion batteries, "the more transmission you have in the system, the longer you can go until storage starts to become really important," said MIT Energy Initiative researcher Patrick Brown, who co-authored the report.

"We set up the study to explore the implications of decarbonizing the system using technologies currently being deployed at gigawatt-scale," said Brown.  "If we end up being limited to those technologies, transmission really emerges as a key factor."

Depending on electrification scenarios, the necessary expansion of interstate transmission capacity to achieve zero carbon could be anywhere from 1.6x to 4x. Transmission improvements and expansions could include development of new high voltage DC lines, expansion of AC transmission links between balancing authorities, and improved operating coordination.

"If you require each state to balance its supply within its own borders, the costs are quite high," said Brown. "As you allow operational coordination and transmission expansion across larger geographic scales ... the costs continually decline."

Similarly, ACEG's Disconnected: The Need for a New Generator Interconnection Policy concludes "a comprehensive approach to building transmission to connect remote power resources to electricity load centers in the Eastern half of the U.S. can ... decrease the average electric bill rate by more than one-third" by 2050.

"We urge U.S. policymakers to support a comprehensive, long-range transmission planning process that optimizes new regional and inter-regional transmission investment across North America," Georgios Papadimitriou, head of Enel Green Power North America, said in a statement supporting the ACEG findings.

ACEG says the current system for interconnecting generators to the transmission grid "is unworkable and inefficient," and that by 2020, U.S. interconnection queues had 734 GW of proposed generation, of which 90% were new wind, solar and storage projects.

The interconnection backlog is raising consumer costs, harming rural economic development, and hampering renewables goals, according to ACEG. 

"This [ACEG] report further demonstrates the urgency in which we need to upgrade and reform our transmission system,” Jay Caspary, report co-author and vice president at Grid Strategies, said in a statement. "We won’t be able to access the benefits of new, clean energy projects by relying on incremental, evolutionary reforms to generator interconnection processes.”

At the highest level, Brown said the MIT study illustrates the value of a national clean energy standard. "If you coordinate at the national level as opposed to individual states, you have the benefit of being able to optimize renewables and transmission siting over the whole system."

The report includes a sensitivity analysis that shows how reductions in the cost of solar, wind and lithium-ion batteries "lead to the lowest electricity costs for systems in which transmission expansion is allowed, while
cost reductions for nuclear power or long-duration energy storage lead to greater electricity cost reductions for isolated systems."

Brown said the report also helps bring into relief how much of a factor is timing. "We should be proactive about developing new transmission capacity given that it takes longer than generation," he said.

The MIT research, The Value of Inter-Regional Coordination and Transmission in Decarbonizing the US Electricity System, concludes that current state-level renewable portfolio standards and regional transmission arrangements "do not capture the benefits of inter-regional transmission or coordination of planning and dispatch for renewable-energy integration."

Brown and co-author Audun Botterud, principal research scientist in the MIT Laboratory for Information and Decision Systems, say the study shows that interstate coordination and transmission expansion "reduce the system cost of electricity in a 100%-renewable US power system by 46% compared with a state-by-state approach," from $135/MWh to $73/MWh.