Skip to main content Skip to secondary navigation

2017 Floating Photovoltaics in California

Main content start


Lake with farm fields rising behind
Floating solar installation at the Kunde Family Winery in Sonoma County, CA

Beginning in June 2017, the TomKat Energy Impact Fellows investigated floating photovoltaic technology and assessed its market potential in the state of California.

The market for solar energy has grown extensively in recent years. Solar energy has become one of the leading choices for individuals, companies, and governments looking to invest in renewable energy.  However, solar energy has a low energy density, so a relatively large amount of area is required per unit energy delivered.  Thus, in places where land is expensive or unavailable for development due to environmental concerns, it is difficult to deploy solar power.  Out of this problem came the idea of floatovoltaics: solar arrays that float on water.

Since 2007, almost 100 megawatts of floating solar installations have been constructed throughout the world, almost entirely in Japan, China, Korea and the UK.  The global market is projected to grow at a CAGR of 45-68% and reach ~3GW by 2024.  Meanwhile, only a handful of installations exist or are in progress in the U.S., mostly at wineries and water treatment facilities.

Floating solar systems are electrically configured similarly to ground-mounted solar arrays, using either microinverters for each panel or large inverters on land that handle several strings of panels each.  Furthermore, floating solar arrays are typically financed using the same methods used for ground-mounted solar: direct ownership, a lease agreement, or a power purchase agreement (PPA).  However, despite the similarities between floating and ground-mounted solar, floating solar comes with its own unique benefits and challenges.

The relevant regulations and necessary permitting for floating solar varies by location due to the different laws regarding water and electricity imposed by state and local agencies.  Because floating solar is still relatively obscure in the US, the permitting process is often slower and more onerous than it is for ground-mounted solar.  Generally, however, installing floating solar on man-made bodies of water is likely to require less permitting work than ground-mounted solar because, in the creation of the man-made bodies of water, those locations have already undergone environmental impact assessments of some sort.

Through the TomKat Fellows’ research, a variety of bodies of water have been found to be ideal for floating solar technology.  The most important factors in determining if a body of water is well-suited for floating solar are:

  • the price of adjacent land,
  • the suitability of adjacent land for ground-mounted solar,
  • the water cleanliness and quality, and
  • the proximity of a grid interconnection point that could handle the power output by the proposed floating solar array.

The full findings of the TomKat Fellows' research can be found in their final report and in the case studies that they performed for floating solar installations at a reservoir and water treatment plant.

Additionally, you can get a quick overview of their findings by reading their flyer or viewing their presentation.  You can also download the estimate toolkit to help you project the floating solar installation size or capacity and ancillary benefits.

Case Study: Reservoir

View and download the case study

Case Study: Santa Rosa Water Treatment Plant

View and download the case study

2017 Energy Impact Fellows

Jessica Gold '20

Jessica Gold self portrait

Mfon Ibekwe '19

Mfon Ibekwe self portrait

Sydney Johnson '20

Syndey Johnson self portrait

Emily Miller '20

Emily Miller self portrait

Dylan Sarkisian '17

Dylan Sarkisian self portait

Kester Wade '18

Kester Wade self portrait