The article says about the building's electrical system:

"This building will operate with carbon-free energy 90% of the time, and we're hoping through operational improvements we'll over the years get to the full 100%," Tahir said.

I am pleased to see the use of the descriptive phrase "carbon-free"
instead of the usual ambiguities like "clean" and "green". Can you
point me to a pie chart showing the breakdown of carbon free sources
used? This is probably answered in a FAQ section somewhere, but I
think a bit of research or inquiry would save time for many MV Voice
readers.

I found a recent explanation of the new Google HQ that adds some
much-needed plausibility that the MV Voice article lacks.

Namely, what some of the carbon-free energy is (wind farms nearby)
and what the geothermal pile system is and does (it’s a big heat pump
system for storing excess heat underground in the summer and retrieving
it in the winter, in both cases using the heat pump for energy efficient indoor
temperature control).

Here's the info on the improved description:

Article: Google opens its Bay View HQ, the first campus it designed itself
Source: Engadget.com (17 May 2022)
URL: Web Link

Here’s what it says:

“This "dragonscale skin" design is actually made up of 90,000 silver solar panels capable of generating almost seven megawatts of energy, or up to 40 percent of the new offices' energy needs. Wind farms nearby will also provide the energy needed to run the all-electric HQ that has two kitchens equipped with electric equipment instead of gas. In addition, the campus has automated window shades to let a lot of natural lighting in during the day and a ventilation system that uses 100 percent outside air. “

"The new campus also houses the largest geothermal installation in North America that will help heat and cool the campus without the use of fossil fuels. It even reduces the amount of water used for cooling by 90 percent. This geothermal pile system uses pumps to absorb heat from the ground during wintertime and to send heat into the ground in the summer."