Solar Substation Costs Hit the Skids

Jan. 11, 2017
Sponsored by S&C Electric Co.

That might be a bit overstated, but solar developers are realizing significant cost and schedule savings with S&C’s skid-mounted substation.  Here’s the backstory:

Until now the solar industry has focused mainly on reducing the cost and increasing the performance of photovoltaic (PV) panels and inverters – and they’ve achieved near parity with conventional generation.  But as solar expands into new locations to accommodate community solar projects, new commercial and industrial customers, and ever-larger distributed generation sites, developers have expanded their focus.  They now want a more cost-effective, reliable, and repeatable means of interconnecting their utility-scale solar projects to the grid – one that utilities will readily accept.

As we all know, substations typically are designed for a particular location then built in place:  Constructors or EPCs assemble all the necessary components – breakers, transformers, overhead metal conductors, etc. – on a site that requires extensive earthwork and construction labor.  Once mounted into position, each piece of electrical gear must then be electrically connected to the other components and tested at the site, increasing schedule time, adding to project costs, and consuming space that could have been used for PV panels. 

S&C’s breakthrough solution is a fully functional factory-assembled, skid-mounted, and utility-grade substation designed and built specifically to connect solar projects to the grid.  This innovative design assembles collection point switchgear, main power transformer, control enclosure, current and potential metering transformers, high-voltage breaker, and disconnect switches on a metal skid that is transported from the factory to the site ready for installation.  And with most of the assembling and connecting work completed at the factory, S&C significantly reduces overall labor costs by as much as 15% while compressing the interconnection schedule by up to 20% compared to the traditional approach.  

Part of the credit goes to S&C’s use of helical piers, instead of the more typical poured-in-place concrete foundations, which can be installed and ready for equipment in days rather than weeks.  This is especially critical in areas with high labor costs.  In addition, an oil containment system attached to each skid eliminates any need to construct an underground containment system.  But other factors set S&C’s skid-mounted design apart, too:

  • The compact design – By definition, if everything is placed on a skid that can be transported to a site pre-assembled and ready to go, the substation is very compact.  This brings added value to solar developers who are trying to maximize the space available for generating revenue, i.e., the PV field.  
  • Substation standardization – For companies operating multiple solar projects in different states, substation standardization not only improves their ability to operate and maintain those facilities, it also leads to predictable costs and construction times.  But with S&C it’s not one-size-fits-all.  The company has the experience and the ability to standardize substation design around every customer’s particular requirements.  Further, S&C can potentially offer additional cost savings for multiple substations in same area.
  • S&C pad-mounted switchgear –By employing enclosed utility-grade switchgear and enclosed connections to the main power transformer, S&C increases both the reliability and the safety of these substations by minimizing the number of exposed high-voltage connections, which are vulnerable to flashovers from animal incursions.  
  • Improved project cash-flow – S&C’s skid-mounted substations enable owners to recoup their investment considerably faster by:  a) compressing the time between ordering major equipment and final commissioning; b) getting large solar plants with multiple substations up and running more quickly; and c) increasing revenue as each substation is commissioned.
  • Real-world experience – S&C is already leveraging its long experience with conventional substations to build skid-mounted substations for solar farms.

The final, and most important, benefit is S&C Electric Company’s long substation experience.  Adding the S&C nameplate to a solar project tells both the utility and regulatory bodies that you are building for the future by employing the best equipment and designs available today.

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