U.S. and India pave way for White Roofs, smarter appliances

by Miguel Sossa on December 2, 2010 · 4 comments

The U.S. and India have teamed up through the University of California Berkeley-India Joint Leadership on Energy and the Environment (BIJLEE) to develop new energy-saving appliances, market strategies, and cost-effective energy reduction techniques. Of their various programs, I really found the white roof concept fascinating.

Per Jayant Sathaye, Co-Director of the  US-India Joint International Program with Berkeley University, the use of white roofs has proven to substantially lower building temperatures and their associated  costs and CO2 output through associated energy consumption reduction. Dr. Sathaye indicated that “If you have 100 sq meters of gray roof and transfer to white, you offset the emission of 10 tons of CO2. If we convert all possible rooftops to white roofs, we would save 24 Gigatonnes of CO2 emissions, the equivalent of pulling 300 million cars off the streets.”

For those of you studying green buildings, energy efficiency, or energy policy, this might be something to look at, as companies such as Walmart are already beginning to implement this strategy and saving a great deal.

Additionally, the organization is looking into creating the market and supply chain necessary to develop the next wave of smart appliances. The industry is moving towards minimal emission and post-life use appliance development, and India has even implemented a much more comprehensive Energy Star rating system to help consumers of both appliances and office space make more conscious purchasing decisions. Perhaps this would be a good thing for SNRE BEC students to look into.

A great session overall, and I would be glad to discuss more upon my return for those interested in these projects.

{ 4 comments }

1 Nick December 2, 2010 at 1:53 pm

That must have been a great talk to attend. I understand that albedo increases when we paint more roofs white, but can you explain how white roofs would result in so much CO2 abatement (avoided energy consumption from air conditioning and other cooling utilities?). Do you happen to know if there are studies that try to compare the CO2 sequestration potential of green roofs vs. the increased reflective capacity (and CO2 abatement capacity) of white roofs?

2 Nick December 2, 2010 at 3:30 pm

I explored the BIJLEE link in your post, and found this:

“Berkeley Lab conducted a one-year experiment in 2006 in Hyderabad on two nearly identical buildings: one with a white roof and the other with a standard roof. The result was a 5 percent reduction in electricity consumption in the building with the white roof. That was enough to convince New Delhi’s Chief Minister to approve mandatory white roofs for all new government buildings this past July. “She saw the benefits immediately and was very enthusiastic,” said Sathaye. “That was a big step forward.””

3 Taylor December 8, 2010 at 4:29 pm

That’s a great idea to implement in India. I’m curious though, how it works when it’s cold outside? It seems to me that if this were to be implemented in some areas of the world that get very cold but not a lot of snow (which would act as insulation on a roof, and be white anyway), that some of the benefits from having a darker roof would be lost. I’m interested in seeing what others think. Thanks!

4 Bob December 9, 2010 at 1:54 pm

In cold climates, a white roof would save less due to decreased absorption, but white also radiates less heat, so less is lost due to radiation. I doubt if that saves as much, but it would be a partial offset. A real study would be a great idea.

Previous post:

Next post: