In the US, the California Public Utilities Commission (CPUC) has released a white paper to help energy stakeholders understand grid integration challenges and solutions.In the white paper released in November 'Beyond 33% Renewables: Grid Integration Policy for a Low-Carbon Future', CPUC believes the process to achieve grid integration is to solve a set of three interlinked challenges as well as harnessing the opportunities they create.

The report predicts increased assimilation of wind and solar resources onto the grid, and response to the changes in system-wide customer load due to increased rooftop solar installations and connected vehicles, will allow California to reach and go beyond its 33% renewable energy target by 2020.

The CPUC said it believes that changes to the characteristics of traditional resources, to the functionality and role of distributed energy resources, to operational and planning practices at both transmission and distribution levels, as well as to wholesale and retail markets will result in the state meeting the new Senate Bill 350 mandate for a 50% renewable target.

The report highlights how California has responded positively and in significant ways to the grid integration challenge in recent years by implementing many programs and policies in partnership with the California Independent System Operator (CAISO).

The commission says it has initiated solutions aimed at providing flexibility for grid integration via distributed energy resources and demand-side initiatives including time of use and dynamic rate design, demand response programme design and distributed storage, smart inverter standards and plug-in electric vehicle integration.

To date, the commission is implementing initiatives aimed at providing the system with more supply-side flexibility in five main categories:

  •    Flexible resource adequacy
  •    Storage procurement
  •    CAISO market mechanisms
  •    Renewable procurement, changes and valuation
  •    Regionalization of real time energy markets

The report gives recommendations on how to expand upon the current activities CPUC is implementing to provide additional flexibility and proposes a long-term vision of the future grid if full incorporation of grid integration into planning, procurement and operation processes takes shape.

Beyond 33% Renewables: Grid Integration Policy for a Low-Carbon Future’ reiterates by presenting primary analyses that must be completed so that the CPUC can understand how best to proceed toward the long-term vision it presents.