Hans De Keulenaer's Library tagged efficiency →  View Popular

It's no small matter. In fact, Chu says that turning all the world's roofs white would eliminate as much greenhouse gas emissions in 20 years as the whole world produces in a year. But some critics point out that in northern cities, the gain in summer could be outweighed by the loss in winter. The ideal situation, then, would be to get the advantage of white roofs when it's hot and black roofs when it's cold.

Now, there may be a way to have both. A team of recent MIT graduates has developed roof tiles that change color based on the temperature. The tiles become white when it's hot, allowing them to reflect away most of the sun's heat. When it's cold they turn black and absorb heat just when it's needed.

Electrified transportation is the use of electrical power to run transportation vehicles and related facilities. Electricity has long been used to power transportation in the Seattle area where 150 King County Metro electric trolley buses serve 14 routes covering 115 miles.

Now electrical power options are spreading to port facilities, medium-duty trucks, school buses and truck stops. Most importantly, electricity is emerging to power cars and light-duty vehicles in the form of gasoline-electric hybrids and plug-in hybrid electric vehicles (PHEVs) which can use grid power and run longer on batteries than regular hybrids.

These options are explored in the FAQ below. These questions and answers are derived from a
2007 ETWG Briefing Report written by Rich Feldman, Apollo Alliance and Patrick Mazza, Climate Solutions.

Compact fluorescent light bulbs are much more energy efficient than incandescent lighting. No arguments there. But is it wise to outright ban the old Edison light bulb in Ontario? Across Canada?

A year ago this writer would have had one answer: Definitely. But the answer, it turns out, shouldn't be so clear cut.

At least that's the conclusion of a recent paper by Michael Ivanco, a senior scientist at Atomic Energy of Canada Ltd., and professor Bryan Karney (along with graduate student Kevin Waher) from the department of civil engineering at the University of Toronto.

The three have authored a study called "To Switch or Not to Switch: A Critical Analysis of Canada's Ban on Incandescent Light Bulbs," and you may be surprised by the findings.

Neuwing Energy Ventures, a New York-based marketer of energy-efficiency certificates, would perform an initial assessment of IBM customers' sprawling data centers -- the massive, air-conditioned facilities that store information and route anything from eBay purchases to e-mail. IBM would identify potential energy savings areas for its clients, and Neuwing would grant the IT firms certificates for the total megawatt-hours no longer needed to cool or operate the data center equipment.

Each certificate would equal 1 megawatt-hour (MWh) per annum, said Rich Lechner, IBM's vice president for IT optimization.

Clients could sell the certificates to utilities subject to state renewable portfolio standards, as well as sell to other companies that aim to reduce their carbon footprint through energy savings. The value of the energy efficiency certificates, historically in the $2-$10 range, is determined by the supply and demand for those certificates in each trading market.