When the sun shines, Google's data centres work harder. That's because it has now developed a new system for its largest data centres that moves the most demanding tasks to times when the lowest carbon sources of energy are most plentiful. 

That's right, the heaviest work is done when the sun is brightest and the wind is strongest. 

Google says this doesn't impact its popular services but, as Ana Radovanovic - Google's Technical Lead for Carbon-Intelligent Computing - explains, it does affect non-urgent compute tasks "like creating new filter features on Google Photos, YouTube video processing, or adding new words to Google Translate".

This initial version of the technology works inside the same data centre, but it could be possible in the near future to move tasks between data centres, so that work is done where it's most environmentally friendly - and presumably cheaper - to do so. 

The system works day-by-day and compares two models that predicts how the power resources of the data centre will be impacted by the environment. Radovanovic explains how these are used: "Then, we use the two forecasts to optimise hour-by-hour guidelines to align compute tasks with times of low-carbon electricity supply.

"Early results demonstrate carbon-aware load shifting works. Results from our pilot suggest that by shifting compute jobs we can increase the amount of lower-carbon energy we consume."

Radovanovic says Google will share its methodology in future so that other organisations can learn how to do this, too. We've recently covered elsewhere how Google is moving toward a more sustainable future - the organisation has been carbon neutral since 2007 and balances out its consumption by buying 100 percent renewable energy.  

Google's eventual aim is to make its data centres transition to completely carbon-free energy.