In 2007, Hölzle announced that Google would be carbon neutral starting that year, using individually selected and monitored carbon offset projects. In the same year, Google started the RE to develop cheaper forms of renewable energy, but four years later Hölzle announced the end of that strategy, dropping development of "solar thermal" electricity (for example with BrightSource Energy) because it was not keeping pace with the rapid price decline of another solar technology – photovoltaics. Starting in 2010, Google began buying renewable energy from new wind and solar farms to cover the energy needs for all its datacenters.Google's Green PPAs https://static.googleusercontent.com/media/www.google.com/en//green/pdfs/renewable-energy.pdf Since 2017 it has been buying enough renewable energy to offset 100% of its usage and now is the world's largest corporate buyer of renewable energy. In 2017, Hölzle received the CK Prahalad Award "for bringing about innovations and radical efficiencies in data center technology and increasing corporate purchasing of renewable energy" and for "not only accelerating Google’s sustainability, [but] also cutting a path for other companies to follow suit.” In 2022, Hölzle was revealed as the primary investor behind the New Zealand based solar developer Helios which aims to build about 10 grid-connected solar farms across New Zealand.
