By Tim Allen, Chief Operating Officer of PXiSE Energy Solutions
One of the main benefits of utility-scale solar farms is that the power they generate doesn’t have to go to one utility. With the right technology, solar farms can support sending power to several different off-takers despite having only a single point of interconnection (POI) with the grid, maximizing the benefit of the solar for its operator and making it easy for utilities and energy providers to pull only what they need from the installation.
The ability to support multiple off-takers also makes solar a more attractive prospect for developers, as the cost of building and operating the facilities can be more easily offset by several potential energy buyers.
Intelligent grid controllers are the key to realizing the benefits of sending solar to multiple recipients. Software-based solutions, which can be deployed at existing solar installations, can help developers maximize their solar installations. One of the best options is a renewable power plant controller (PPC).
Subscribe today to the all-new Factor This! podcast from Renewable Energy World. This podcast is designed specifically for the solar industry and is available wherever you get your podcasts.
Listen to the latest episode featuring Ben Catt, CEO of Pine Gate Renewables, who breaks down the state of clean energy capital markets and the impact of the Inflation Reduction Act.
Designed to help optimize the efficiency and production of any combination of batteries and renewable energy assets, PPCs utilize real-time asset monitoring and optimization, consolidating disparate system controls and visualizations into a single platform. A PPC gives developers the tools they need to manage sending power to multiple off-takers and can do so according to their particular needs. PPCs can also help manage power delivery, keeping the grid stable in times of fluctuating solar availability.
Located in California’s Central Valley, the Great Valley Solar Project is one such facility where the developers needed to provide unified controls and visualizations to deliver power to several off-takers. Consisting of a 200 MW solar PV farm in Cantua Creek, the Great Valley solar farm spreads across 1,633 acres of retired agricultural land. Roughly 860,000 panels generate around 582,259 MWh of electricity – enough to power 90,000 households. While Great Valley had an existing PPC, it struggled to efficiently deliver the maximum amount of power to separate customers, highlighting the need for a controller that could meet these conditions.
At Great Valley, generated power is distributed to four off-takers, all of whom have separate long-term power purchase agreements (PPAs). The PPAs on the facility are long-term agreements spanning upwards of 20 years, and each utility has a unique rate structure within its PPA. On the Great Valley solar farm, the four off-takers include Marin Clean Energy, Sacramento Municipal Utility District, Pacific Gas & Electric, and Southern California Edison.
While the power flows to the grid through a single POI, the PPC software digitally divides the facility into four distinct sites, enabling operators to manage each separately through the same unified dashboard. From this single control panel, operators can monitor and control signals sent to the solar PV inverters, tracker controllers, and cap bank breakers – while automatically capturing data history.
The controller handles remotely sent setpoints and constraints, dispatching appropriate signals that are aligned with each site’s PPA and business objectives, and then aggregates the four sites through the single POI to remain in compliance with the California Independent System Operator (CAISO). Functions such as transformer condition assessment, event detection, and equipment status review are all centralized, along with an ISA 18.2 standard alarm system.
Operating year-round, the solar farm faces weather variations throughout the year, experiencing mostly sunny conditions in the summer and cloudiness in the winter – with overcast skies nearly 50% of the time. The PPC software uses artificial intelligence to interpret weather forecasts and predict intermittency. It mitigates voltage and frequency fluctuations, minimizes distortion throughout the collection systems between the four sites and the POI, and optimizes capacitor performance.
All this results in a highly reliable amount of power, virtually eliminating energy waste and maximizing the return-on-investment for the farm operator, while ensuring compliance with PPA, utility and CAISO constraints.
About the author
As Chief Operating Office of PXiSE Energy Solutions, Tim Allen plays a critical role in forming partnerships that help utilities and other organizations maximize their clean energy projects. Before joining PXiSE, Tim served as Managing Director of EPC at Recurrent Energy. He also spent 10 years overseeing renewable projects at Sempra Renewables, and over eight years working on electrical projects at San Diego Gas & Electric. Tim is a proven leader in the renewable and electric utility industry, focused on enabling the continued growth of the renewable energy industry that is rapidly integrating energy storage.
