Green Electricity Opt-Out Default

Summary

Simply making green energy the starting position—requiring households to actively switch away rather than actively choose it—increased adoption by nearly tenfold. The effect holds across income levels, regions, and household types. This is one of the strongest demonstrations of default power in a domain with meaningful individual financial cost, since green tariffs typically carry a small premium.

Research question

"Does setting green energy as the default tariff increase adoption compared to opt-in?"

Methodology

Result

Positive

Opt-out adoption: 68–94% vs. opt-in: 7–41% (roughly 10× difference)

Evidence strength

Strong

Randomized trial, replicated across multiple sites or studies.

Replication status

Replicated