Google’s highly ambitious goal to power all its data centers with clean energy on a 24/7 basis could get a boost from an in-house experiment that shifts server computing loads in response to the carbon-intensity of the grid at a given time — if it can be scaled up across its global data center fleet.

Google’s “carbon-intelligent computing platform” pilot project taps the flexibility of when data centers schedule “non-urgent” tasks, such as processing YouTube videos and adding new words to Google Translate, to match that work to times when wind, solar and other carbon-free resources are at their peak generation capacity on the grid that powers them.

The latest results from an unnamed data center show that "carbon-aware load shifting works,” Ana Radovanovic, Google’s technical lead for carbon-intelligent computing, wrote in a blog post this week. To correlate server loads with times of maximum clean power on the grid, Google matches day-ahead hourly forecasts of grid “carbon intensity” provided by Denmark-based company Tomorrow with internal forecasts of the electricity needed to run its compute tasks over the same time period.

The graph below indicates “how the new system shifts compute from our baseline (dashed line) to better align with less carbon-intensive times of the day — such as early morning and late evening (solid line) — when wind energy is most plentiful,” Radovanovic wrote.

Gray shading represents times of day when more carbon-intensive energy is present on the grid. These changes are made without additional hardware and don’t affect the operations of computing tasks in constant demand like Google’s search engine or YouTube videos.

While the pilot was limited to a single data center, “it’s also possible to move flexible compute tasks between different data centers,” and Google’s “plan for the future is to shift load in both time and location to maximize the reduction in grid-level CO2 emissions,” she wrote.

Radovanovic confirmed in an email Wednesday that the same technology platform will be tested across its global data center fleet in the coming months, and that Google, which is owned by Alphabet Inc., will release research papers later this year detailing its methodology and performance results of its global rollout.

She declined to comment further on how the company plans to put these capabilities to work in those data centers and how they might help it meet its ambitious goals for powering its data center fleet with carbon-free power.

Load flexibility: The next frontier in greening data center operations?

Google and other major tech companies like Facebook and Microsoft have been pursuing aggressive clean energy strategies for years, driven by corporate sustainability goals, a desire to lock in energy prices, and to counter criticism from groups like Greenpeace over their rising consumption of global electricity production to keep the internet running.

Google started by buying power directly from existing wind and solar resources, or purchasing the energy and selling it to local utilities to retire the associated renewable energy certificates, which greens a corporate energy profile but don’t lead to “additionality,” or new renewables being built. It’s since moved on to committing to purchase power from new wind and solar farms, such as last year’s plans for 1.6 gigawatts of renewables in 18 deals across the U.S., Europe and Chile.

Since 2017, Google has been able to procure enough renewable energy to match 100 percent of its overall electricity consumption on an annual basis. But that still leaves many of its data centers consuming power from grids that rely on fossil fuels for a majority of their electricity.

In 2018 Google outlined a plan to move toward “sourcing carbon-free energy for our operations on a 24x7 basis,” or, in other words, to “match our electricity consumption in all places, at all times.” That’s a far more ambitious goal, one that's largely reliant on the utilities and countries that serve its global data center fleet, from nearly carbon-free power in Finland to largely fossil-fueled power in Virginia.

Google has become a member of regional transmission organizations in the Midwest to have a “seat at the table” among market stakeholders, Neha Palmer, Google’s director of operations and the lead on the company’s energy purchasing, told Greentech Media last year. It’s also pressured utilities like Virginia’s Dominion Energy, which now faces the prospect of converting to 100 percent clean energy by 2045 under a state law passed this year.

Shifting data center operations to match the availability of clean energy on the grid has been studied for a long time, Wood Mackenzie Power & Renewables microgrid analyst Isaac Maze-Rothstein noted in a Wednesday interview. Microsoft outlined the concept in a 2013 research paper, Maze-Rothstein said, adding, "There are a lot of white papers since then laying out this idea.”

Batteries used for data center uninterruptible power supply systems are also potential targets for providing flexible power, Maze-Rothstein noted. Eaton is testing such a system at its Ireland headquarters, and Microsoft has tested a similar concept in a data center in Washington state.

But data centers prize reliable operations above all else, making any practices that might interfere with the steady and predictable flow of energy to their servers a tough sell, Maze-Rothstein said. That’s particularly true for co-location data centers that rent server space for other customers and operate under strict performance contracts.

“This is primarily useful — only useful perhaps — for data centers that control the data center and the streams of data themselves,” such as Google, he said.