I think we have it. DisplaySearch has a table on LCD monitor penetration rates by region, which we can use to adjust our "Black Google" number. The table is interesting in itself, indicating over 99 percent LCD penetration in Japan, and only 37.2 percent in Latin America. Worldwide, as of first quarter 2006, they estimate LCD penetration at 74.7 percent.
Therefore, making the same assumptions as before, we can reduce the original 3000 Megawatt-hours to about 750 Megawatt-hours for "Black Google". Check out Alexa's Global 500 for a hint on how much juice could be saved; Yahoo, for instance, serves up 3.4 billion (mostly white) page views a day. Or Qq, the Chinese instant messaging service, with 9 million users using their (mostly white) interface at any given time.