Mildly Infuriating

Sending the JavaScript to do this literally uses more electricity than this saves.

It's only going to save power if you're using an oled, since for most lcd screens the backlight is on whether you display black or white.

All my websites are jet black, and the black is only really black on my phone which has an oled screen.

Either way, it's just greenwashing. These companies are only pretending to give a crap so they can get brownie points with people who can't see what they're doing.

Back in CRT days, the difference between full white and full black could be as much as 100W. Before dark mode existed, people developed sites like Blackle to reduce the power usage of Googling.

Traditional LCD screens actually use more power to make black.

OLED screens might save a tiny bit of power though.

They can't do any good in the world. This is the best they have to offer.

I wish it was that easy, but nestle has taken almost 80% of global middleman positions in the food market, they have become a pseudo monopoly in the food industry.

Many phones have OLED displays, which physically turn off the pixels in black areas. Since the site is on mobile, it does make a bit of sense.

In case you are using an OLED screen or one of its variants, the difference is noticeable since they turn off the pixels that are black and, therefore, less electricity is consumed.

But you can compensate by giving them your ground water.

For oleds, it makes a difference and not an insignificant number of smartphones today use OLED screens.

However, if the microwatt-hour of battery saved by browsing a shitty website of a shitty company for a few minutes saves the planet is another story...

It kinda does if your screen is OLED. The black pixels are actually turned off on OLED screens.

On other type of screens - like LCD - the backlight is always turned on

The vampires of the Nestlé board don't like being blinded by bright screens as they roam the night in search for the blood of the innocent.

It should honestly just default to whatever the system is set to, because that's likely what the user prefers.

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.

dark theme › slower battery usage › charging less often › less electricity usage › less coal power plants › less emissions › solved global warming. It's simple really.