Watt-Wise Game Jam


Build delightful games that use as little energy per second as possible in order to make games and computing more sustainable, and to discover new directions for software aesthetics.



Watt-Wise is a challenge to build low-energy games. Entries will be judged both for the quality of their gameplay experience and for the average energy consumed per second of gameplay (using a hardware monitor between the computer and the power outlet).


Computers and video games have an enormous carbon footprint 1 2 3. We can minimize the carbon footprint of running games on non-renewable power grids by using less power, but this is actually the lesser goal.

By focusing our jam on low energy use, we also target the ability for older hardware to run it. How? Well, the physics definition of “energy” is the “capacity to do work”. If program X uses more energy on my computer than program Y, it’s because it actually does more computation. There are differences in the efficiencies of certain tasks enabled by hardware, of course. GPUs make lots of 2D and 3D math vastly more efficient that pure-CPU approaches. However, we can compare two programs on the same hardware (while holding factors like clock speeds constant) to compare how much energy is required for them to function. The program using less energy does less work on that hardware, and is likelier to run better on even older hardware.

The end goal isn’t just to build some great games, but to discover which techniques of game and software design are both beautiful and efficient, and to apply those lessons to software beyond video games.


We are developing both hardware and software estimation techniques for measuring energy consumption. Participants can use our open source power estimation tooling while developing their games to optimize for using less power. When it’s time to judge games, the community will rank their favorite games, and then the judges will play those games and measure their hardware consumption using a more precise hardware monitor. The games that strike the best balance between fun gameplay and low energy consumption win!

You can find an explanation of the scoring rubric used to evaluate games here.


How do I join?

Join one of our online communities to get the latest news, discuss game ideas, find collaborators, and more. Join us on Itch.io and Discord or IRC to get involved.

Is there a theme?

The theme is not a factor in determining the score of entries, but we do have one. In 2024, our theme is “Breaking and Re-Making.” Whether that’s relationships, objects, ecologies, worlds, bones, or anything else is up to you.

Can teams participate, or only solo game developers?

Teams are welcome!

Can I submit an existing game, or does it need to be a new one?

We will accept two categories of submission:

We’ll evaluate the two categories separately and recognize excellence within each category. That way optimized games are only compared against other optimized games, and new games are only compared against other new games.

What restrictions are there for submissions?

Games must:

How do I make a game energy-efficient?

The simple answer is “make your game do less work,” but there are many ways to go about that. Let’s think about what your game does as it runs:

If we call your tick rate tps and your frame rate fps, and we call the cost of one tick and one frame Ct and Cf respectively, we can model your energy cost per second as:

tps * Ct + fps * Cf.

The most obvious wins come from decreasing tps and/or fps, since they are static multipliers on the cost of running your game every second.

TPS and FPS Optimizations

In your game, you may be able to update some sub-states of your game world (physics, AI, networking, etc…) far less often than others. This lets you save work per-tick. There’s a delicate balance here, espcially for physics-based games, but doing fewer game ticks saves energy.

For FPS, a number of optimizations are available:

Cost of Tick Optimizations

However, there’s a limit to how much you can decrease these while keeping your game feeling pleasant and interactive. Instead, let’s focus on optimizing Ct and Cf.

Ct is the cost of updating the state of your game. Depending on what kind of game you are building, there are many different things you could be doing. However, the best way to decrease this cost factor is always the same: make thoughtful choices about how much of work your game needs to do in order to be fun. If your game keeps track of physical objects, carefull consider how many of them you really need and how realistic their physical behavior needs to be.

Also, stop updating your world state when the player can’t see it anyway, like when they’re looking at a menu.

Cost of Frame Optimizations

Cf is the cost of drawing one frame. Here, we can consider many ways of doing less work that are relevant for many games:

Some games may be able to combine many of these optimizations to great effect.

TODO: there’s a lot more to say here. Check back later.