Mildly Infuriating

Edit: I tried updating this, when I submitted sh.itjust.works was down and I lost it… the edit that is. Anyway I have now updated some grammar and put in some more context AND a tl;dr at the bottom. All for the low low price of my hyper focus.

Alright, it’s math time.

A quick google comes up with this blog post, which I haven't vetted or even read at all, it just has a table with some stats https://dodonut.com/blog/does-dark-mode-save-battery/. I should probably also mention that I am going to use the most impressive savings in the following. Actual savings may be as little as a 4th.

Apparently going to dark mode with 100% brightness provide a net saving of 40% on a pixel 2. Let's assume this is universally true for all OLED and AMOLED displays, LCD users won't see a difference, neither will CRTs but .. I don't think that I've heard of a CRT display on a phone.

40%? That sounds like a lot, doesn't it?

Well yes and no, in relative terms it's impressive, but it really depends on absolute terms. So how much does a phone use? The pixel 2 from before comes with a 10.39Wh battery, let's assume an average use of 80% per day, then that comes out to 8.32Wh per day per phone. That means that the 40% reduction is 3.33Wh daily.

Is that a lot? Depends, if your only power source is a potato with a bit of copper and a galvanized nail, then yes, otherwise no.

Over the course of a year 3.33Wh a day comes to 1.215kWh.

Let's put that into some context. The largest Vestas offshore wind turbine is the 15MW V236 https://www.vestas.com/en/products/offshore/V236-15MW. It can produce 80GWh annually. With the saving of 1.215kWh per phone, then for every approx 66 million OLED phones, we can skip erecting one offshore wind turbine.

But let’s look at a global impact. As of yesterday there were 8.05 billion people breathing on the planet. Let’s say they all achieve the maximum saving of 1.215kWh annually. That’s 9.78TWh. Presently there’s a handful of projects planned with the V236, https://www.offshorewind.biz/2023/04/03/vestas-15-mw-prototype-now-at-full-throttle/, totalling 7.3 GW, 486.6 units (I’ve got the figures for each project and added them up, so the number of units is an approximation) or 38.9TWh annually. So get everyone to achieve maximum saving, with technology most doesn’t have, and we can save a quarter of the planned pre-order of a turbine model that isn’t even done with testing.

tl;dr: dark mode does save power, but at best its effect is miniscule, and realistically utterly insignificant.