Implications of natural gas as a “bridging” technology

To achieve the ultimate goal of the Paris Agreement, all emissions from fossil fuel combustion must cease. And yet some of the electricity scenarios that Swiss policy-makers have been discussing feature natural gas as a “bridging” technology, ensuring reliability from renewables until enhanced means are available for electricity storage.

The NRP 70 project „Trade-offs in switching to renewable electricity“, headed by Anthony Patt at ETH Zurich, explored whether it is possible for Switzerland to make the transition to 100 percent renewables without new natural gas capacity, without massive new investments in energy storage, particularly seasonal storage.

The study reached two key findings: First, it is very important whether all of the wind and solar power that we use is produced domestically, compared to importing some share of our renewable power from regions with more reliable generating conditions. For a purely domestic supply scenario, Switzerland would require natural gas as a bridging fuel, but even modest imports could eliminate the need for gas, while also reducing costs to consumers.

Second, with modest imports of renewable power, there are no clear cost advantages to installing gas power plants. It is uncertain how expensive new wind and solar power will be in the future. Assuming costs continue to fall substantially, the least cost options for Switzerland involve no natural gas at all. Even with cost projections at the more pessimistic end of the range, relying on natural gas as a bridging fuel would reduce system LCOE (Levelized Cost of Electricity) values by only 3 percent, compared to the least-cost renewables-only system.

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• Trade-offs in switching to renewable electricity