#568 2015 · Ebeling & Lotz field experiment (German electricity utility) · Energy / utilities
A German utility got ten times more customers onto pricier green power without changing the price or the pitch
问题
Getting customers to switch to a more expensive but environmentally preferable option normally means persuading them — advertising the environmental case, offering a discount, or otherwise arguing them into paying more for the same underlying service — and persuasion campaigns for a price increase, however small, typically convert only a small minority of customers
背景
German electricity customers could choose a green-energy tariff sourced from renewable generation at a small premium — about 3 cents more per kilowatt-hour, roughly $15 a year for a typical household — over the standard grey-power plan. Under the conventional opt-in structure, where customers had to actively select the green plan to get it, uptake stayed low: economists Felix Ebeling (University of Cologne) and Sebastian Lotz (Stanford) found only about 7% of an opt-in group chose it.
Ebeling and Lotz ran a field experiment with roughly 42,000 German households, randomly assigning customers to either the standard opt-in green tariff or a version where the green tariff was the pre-selected default and customers had to actively opt out to get cheaper grey power instead. Nothing about the price, the underlying electricity, or the marketing pitch changed between the two groups — only which option required action to select.
换别人会怎么做
Run a persuasion campaign for the green tariff -- advertise the environmental benefit, explain the small cost difference, maybe offer an introductory discount -- the standard playbook for moving customers toward a costlier option, which reliably converts only a small minority no matter how well the case is made.
他们看到了什么
Ebeling and Lotz saw that the 7% opt-in rate wasn't measuring how many customers actually preferred grey power -- it was measuring how many customers cared enough to take an action at all. Most people don't evaluate the choice each time it's presented; they just keep whatever requires no decision, so changing which option was the passive one would change the outcome more than any argument could.
那一手
By making the greener, more expensive plan the default rather than the plan customers had to actively choose, the utility converted the same environmental and financial pitch into a dramatically higher acceptance rate — not because customers were persuaded differently, but because staying on the default required no action while switching away from it did.
为什么管用
Because the price, the product, and the marketing pitch were held completely identical between the two groups, the tenfold jump in adoption isolated the effect of the default itself: staying on green power required zero effort in the opt-out condition, while under opt-in it required a customer to actively seek out and select the pricier plan. Most customers simply stayed with whatever didn't require action, so the default converted latent indifference into apparent preference without persuading anyone of anything new.
值了多少
About 69-70% of customers in the opt-out group stayed on the green default, compared to roughly 7% who actively chose it under opt-in — a roughly tenfold increase in green-tariff adoption from the identical price and product, published in Nature Climate Change in 2015.
什么时候会失灵
The approach depends on the switching cost of opting out staying genuinely low and the choice staying low-stakes enough that customers don't bother to override the default -- for a decision customers actively monitor and care about, a default can just as easily provoke a backlash at being auto-enrolled without clear consent. It also only works once: a population that becomes aware defaults are being used to steer them, or that faces repeated default-based nudges, may start scrutinizing and opting out at a much higher rate than an unsuspecting first-time population would.
后来呢
The study became one of the most frequently cited field demonstrations of default effects in energy and environmental policy, cited in subsequent research on green-energy defaults across household and business sectors and used by utilities and policymakers designing opt-out rather than opt-in enrollment for sustainability programs.
资料来源
- [1]Phys.org — Researcher identifies strategy to guide consumers to green energy choicesPhys.org, 2015phys.org
- [2]Nature Climate Change — Domestic uptake of green energy promoted by opt-out tariffs (Ebeling & Lotz)EconPapers / RePEc (Örebro University), 2015econpapers.repec.org