| Work Detail |
Fossil generators sharing their interconnection point with renewable generators could be a “dominant strategy” for integrating solar, wind and storage “at speed and scale,” four researchers say.
Some 500 GW of economically viable solar power could be located within 10 km of a fossil-fired generator in the US and share that generators grid interconnection, reports a working paper by four researchers at the University of California, Berkeley.
The simplicity of the concept is shown in the following diagram. At any given time, the combined output of the two generators could not exceed the capacity of the interconnection point.
According to the authors, the idea of ??shared interconnection has been debated for years, but falling costs for renewables and recent political developments "have sparked new commercial interest, particularly in the integration of solar power into existing fossil power plants."
The working paper also examines the potential for wind power to share interconnection with fossil generators, and concludes that the shared interconnection potential for combined solar and wind capacity is more than 800 GW.
The paper finds that renewables sharing interconnection are economically viable only at sites where the “levelized cost” of solar or wind generation is lower than the variable cost of the fossil power plant, which consists of fuel costs plus variable operation and maintenance costs. That economic viability criterion was met at more than 75% of fossil generators. Storage could also be added at such sites.
A dashboard referenced in the paper shows all 1,400 U.S. fossil generators and the potential for shared interconnection capacity for each of them. The dashboard also allows the user to apply filters to the entire data set and see the resulting aggregate potential.
Shared interconnection is also known as surplus interconnection. Federal Energy Regulatory Commission (FERC) Order 845 requires transmission providers to establish an expedited process for interconnection customers to use or transfer what FERC calls “Surplus Interconnection Service.”
To accelerate the deployment of renewables at existing interconnection points, the working paper offers three pages of policy recommendations that could be implemented by FERC, grid operators, public utility commissions and others.
Non-profit consultancy GridLab has published a “surplus interconnection policy explainer” in coordination with the publication of the working paper.
The working paper states that from an electricity system perspective, integrating more renewables while preserving conventional fossil assets “ensures the availability of sufficient generation capacity to meet rapid load growth, supporting grid reliability.”
According to the document, there is a “significant opportunity” for shared interconnection in the U.S. grid regions known as PJM and MISO. “The opportunity in PJM is especially acute” given PJM’s “significant challenges in maintaining resource adequacy due to increased electricity demand.”
The paper notes that U.S. coal and oil plants are on average more than 40 years old and that “this aging infrastructure is taking up increasingly valuable interconnection points at a time when new renewable energy generators are having great difficulty accessing the grid.”
The working paper also notes the opportunity for existing renewable generators, which have a combined capacity of 250 GW, to share their interconnection capacity with an additional 250 GW of storage, “thereby adding significant new firm capacity to the U.S. grid while creating opportunities for an additional 250-500 GW of renewables to be deployed that can share the same interconnection.” The authors say that several renewable projects are already adopting such strategies.
The authors, pointing to their previous research showing that re-routing transmission lines with advanced conductors could double U.S. transmission capacity, say that “the combination of a focus on renewables, surplus interconnection, and re-routing can pave the way for an abundance of low-cost, clean energy.”
The working paper is titled “ Existing fossil fuel plants sharing grid access with renewables can rapidly and cost-effectively double US generation capacity.” |
