Electric Renewable Resources

Renewable Portfolio Standard (RPS)

In 2015, California adopted one of the most aggressive Renewable Portfolio Standard (RPS) policies in the country, requiring that all utilities in the state supply 50% of their retail electric sales from eligible renewable energy resources by 2030. However, the City has been pursuing renewable resources for over a decade (having voluntarily adopted its own RPS target in 2002), and as the chart below shows, is on track to exceed the 50% RPS level in 2017. The City is also continuing to aggressively pursue energy efficiency measures in order to ratchet down its total electricity consumption, and thus reduce the volume of renewable energy purchases that are needed to satisfy its RPS requirements.

Carbon Neutral Portfolio

In 2013 the City formally adopted a Carbon Neutral Plan, which commits the City to providing its customers with a 100% carbon neutral electricity supply. The City’s electric supply portfolio contains a variety of resources that are considered by the state to be "eligible renewable energy resources," which means that these resources can be counted towards the City’s RPS target. In addition, the City for many years has received electricity from large hydroelectric resources that provide a carbon-free power supply, but under California’s renewable energy eligibility criteria do not count towards the RPS target. The chart below shows that, even in a severe drought year like 2015, approximately half of the City’s electric supplies were carbon neutral. (And in a “normal” hydrological year, over three-quarters of the City’s electric supplies would have been carbon neutral.) The City’s Power Content Label provides additional information about its electricity supply.


The City currently receives power from two large-scale solar projects, with three more under contract that are expected to begin operating by the end of 2016. At that point, the City will be able to provide its customers with a 100% carbon neutral electricity supply exclusively through its long-term renewable resource and hydroelectric contracts (under normal hydrological conditions). However, before all of those solar projects come online, as well as in drier than normal hydro years, the City plans to maintain its carbon neutral electricity supply through the purchase of renewable energy certificates (RECs) to compensate for the generic market power purchases that the City is required to make in order to satisfy its overall electricity demand.

Carbon Content of the Electricity Supply

Another way to illustrate the “carbon content” or “carbon intensity” of the City’s electric supply portfolio is to show the amount of carbon dioxide equivalent (CO2e) greenhouse gas emissions generated for each megawatt-hour (MWh) of electricity delivered to the City’s customers. The chart below illustrates the downward trend of the carbon content of the City’s electricity portfolio since 2005. This is largely due to the increasing purchases of renewable power supplies. This downward trend is expected to continue in the future as more renewable supplies are added to the portfolio.  Click to view the 2017 Residential and Commercial Power Content Labels. 

The chart also shows the carbon content of the portfolio adjusted for an average hydrologic year, since some years are wet (resulting in more hydroelectric generation) and some are dry (resulting in less hydroelectric generation). For example, 2006 was a very wet year, so market purchases of electricity were minimal. On the other hand, we are currently experiencing historic drought conditions, which require the City to make more market purchases of electricity to meet all of its supply needs.

Map of the City of Palo Alto's Renewable Power Project Sites
Last Updated: Nov 1, 2017