Concluding that the low-hanging fruit is simply to get people to switch things off, a group creates visually appealing kits for teaching simple conservation messages.

A Brazilian oil executive predicts that oil demand will be met in coming decades as products get more efficient, cars get lighter, home construction improves and mass transportation gets better.

This year, 245 buildings — including hospitals, schools, banks and churches — are competing to reduce their energy consumption, up from 14 last year.

Set-top boxes in the United States consume nearly as much energy when not in use as when they are on, costing a cumulative $2 billion a year.

An environmental professor believes that simple tools for energy conservation already exist but that rich nations choose not to deploy them.

The site will get its electricity from trigeneration generators, a system where heat, mechanical energy and cooling are created from a single source, harnessing “waste heat” to raise overall output.

Carpooling ventures now rely on smartphones, G.P.S., reward points and micropayments.

A smart meter and a holiday vacation awaken a homeowner to how much energy his family consumes — and how much appliances consume when not in direct use.

A smart meter and a holiday vacation awaken a homeowner to how much energy his family consumes — and how much appliances consume when not in direct use.

Over the last week, gasoline prices rose from $2.90 to $2.98 a gallon; that’s 35 cents higher than a year ago. And analysts expect them to rise further in the spring.