As intermittent renewables come to represent a larger share of the energy mix in regions the world over, ensuring that energy is available where needed, and that electricity continues to run reliably, becomes more of a challenge.
Energy storage will play a key role in balancing grids powered by renewables. However, interconnection between countries and regions can be an effective alternative – since the regions will have different climates, weather patterns, and resource profiles, and importing energy between them serves to balance supply and demand on the combined grid.
Regional grid interconnections are the subject of new research from Stanford University’s Mark Jacobson. The latest paper examines various interconnection scenarios for 14 western-European regions (Belgium, Denmark, France, Germany, Gibraltar, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, and United Kingdom), based on all regions meeting 100% of their overall energy demand (not only electricity) from wind, water, and sunlight.
The study compares the costs of ‘fully interconnected’ versus ‘completely isolated’ grids in various iterations across the regions studied, taking in climate forecasts, grid integration data, and energy demand profiles. Full details of the model can be found in the paper The cost of grid stability with 100 % clean, renewable energy for all purposes when countries are isolated versus interconnected, published in Renewable Energy.
In every scenario modeled, the study found that interconnection resulted in lower energy costs and better grid stability than isolation. “The main implication of this work is that interconnecting countries can usually serve as an additional benefit to grid stability and cost reduction in a 100 % clean, renewable energy world,” reads the paper. Jacobson goes on to note that even for grids relying on fossil fuels, interconnection can serve to increase reliability and act as a hedge against unexpected events. “An isolated grid that has no outside electricity support may fail during an extreme weather event, as it did during the February 14e18, 2021 Texas storm,” Jakobson stated. “Such an outage could happen in any isolated grid.”
The model calculated that interconnection across all of the regions would make energy costs around 13% lower than in the isolated scenario, with the largest benefit coming from connecting Norway with Denmark and the rest of northwestern Europe, taking advantage of the Nordic country’s large hydropower capacity to bring about a 20.6% cost reduction.
While the cases compared in the study – full interconnection and complete isolation – don’t reflect the reality that most energy systems in Europe are interconnected to some degree, and will likely remain somewhere in between the two scenarios. Political limits to interconnection also complicate the picture further: “Limits can also arise if one country doesn't want to cede too much reliance of its energy security on the goodwill of its neighbors, fearing that a neighbor may shut off the electricity supply during a conflict,” the paper states. “This risk must be balanced by the lower cost and increased efficiency of a well-interconnected system.”
However, Jacobson states that these models can still allow relevant conclusions. “Showing that grids can stay stable at low cost with 100 % WWS and storage in both the isolated and fully-interconnected cases suggests they can stay stable at low cost in cases in-between,” he states in the paper. And though reality may add in some more complicating factors, the paper draws a clear conclusion that in most cases, increased interconnection will be a valuable tool in building low-cost, reliable energy systems reliant on 100% wind, water and sunlight.
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