Just had a thought: How much energy could be saved if everyone got up at sunrise? Perhaps it would have a counteractive effect somehow but my thought is that if you're up less during hours that it's dark you wouldn't need to have your lights on during those hours.
The best analogy for this is the use of daylight savings time, where in effect people wake up one hour early than they usually do.
A study by the US Department of Transport in 1975 (see page 4 of the website),
showed that Daylight Saving Time trims the entire country's electricity usage by a small but significant amount, about one percent each day, because less electricity is used for lighting and appliances.
Although a 1976 report by the National Bureau of Standards disputed the 1975 U.S. Department of Transportation study, and found that DST-related energy savings were insignificant.
A more recent report, referenced by the California Energy Commission states,
The study concluded that both Winter Daylight Saving Time and Summer-season Double Daylight SavingTime (DDST) would probably save marginal amounts of electricity - around 3,400 megawatt-hours (MWh) a day in winter (one-half of one percent of winter electricity use - 0.5%) and around 1,500 MWh a day during the summer season (one-fifth of one percent of summer-season use - 0.20%).
So the energy savings would be small.
Edit: Additional data on potential energy usage & savings from Daylight Savings
Thanks for @Stempie for the additional data.
According to the Initiative Neue Marktwirtschaft (Initiative New Market Economy) [German language], by way of example, in 2010 Germany used 600 - 650 TWh of electricity.
An average nuclear plant produces about 1.4 - 1.5 GW, which is 11 TWh/year. An over average bituminous coal plant produces about 1.7 - 2 GW, 12 - 14 TWh/year.
So this means, 0.5% of the total German energy consumption in 2010 was about 3 TWh was slightly more than a quarter the output of either a large coal plant or a nuclear plant.