# How much energy could we save if we all got up at sunrise

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.

• Maybe it would make more difference if we all went to bed at sunset! May 19 '15 at 3:19
• Yeah, how many people these days get up long before sunrise? May 19 '15 at 11:33
• How many people would use significantly less lighting if they get up at sunrise? I don't get a lot of light in my home's north-facing windows, so I use the lights even when I get up well after sunrise. Not that lighting is a big consumer of electricity, my lights are mostly 11W LED's, so if have 5 lamps on for 4 hours a day to make up for getting up before sunrise, that's 20KWh/year, about .8% of my total household power usage. May 19 '15 at 20:14
• Difficult to say as it so much depend on the activities an individual performs. Maybe we even experience a rebound effect of people getting up earlier but sleeping less and spending the time on consumption of energy and materials (food, goods, services)? May 20 '15 at 9:10
• Much of renewable energy (hydropower, wind power) is generated without paying attention to the time of day, so sustainability-wise any Watt that you can use in the early morning so that you don't have to use it during peak time is a way to reduce the load on peak time electricity, which is often generated with fossil fuels. (This only applies to areas, where the electricity grid contains some "renewable electricity".) May 28 '15 at 20:27

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.

• If you would add the math from my answer, I'd delete mine and would call youes "perfect answer" ;-)
– jawo
Jun 29 '15 at 11:11