Efforts to reduce the environmental impact of our digital world tend to start with the cooling systems at data centers, and rarely get any further.

The tech industry created PUE as a simple metric which could express how efficiently power is delivered to the racks, but did not consider what happens to that power when it gets there.

That’s not good enough, because poorly written software could be wasting that power in unnecessary loops and fruitless calculations.

The Green Software Foundation has emerged to propose a measure of Software Carbon Intensity that will tell developers if their software is a good planetary citizen.

But this is an issue that gets more complex, the more you look at it. Software that completes quickly must save energy, but what if the software is running on multiple hardware platforms? What about the embodied energy of the hardware you choose for it?

David Mytton is Co-founder & CEO of Console, a company that makes tools for developers. He’s also looked at the energy used in technology, bothy at Imperial College and at the Uptime Institute.

He’s now working on a PhD in sustainable computing at the University of Oxford.

He talks to us about the prospects for Green Software finding its way from academic research, through sponsorship by large vendors, into the hands of developers and consumers.