UK-based The DoNation empowers thon participants to ask friends not for money, but rather to adopt certain behaviors that will reduce their carbon footprint such as cycling to work, installing solar panels or eating less meat.
Costs not captured include electrical grid upgrade, connectivity of renewables and buffering of their intermittency by rapid cycling of fossil fuel plants as presently practiced in this country, and non-carbon-tax externalities such as pollution and health care costs associated with energy sources, especially for coal.