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Top-tier engineering & design for utility-scale solar projects

Castillo Engineering has grown to become the leading design and engineering firm for high-quality utility-scale solar and energy storage projects as a result of the firm’s 25+ years of solar engineering experience, minimal bill of material designs, fast turnaround times, and strong industry relationships.

Our solar farm expertise include:

  • Utility-Scale

  • Distributed Generation (DG)

  • Solar + Storage

  • Community Solar

  • Landfills

  • Fixed Tilt 

  • Trackers

  • Microgrids 

  • Rooftop

  • Floating Solar

Schedule a meeting with one of our solar and storage experts

Solar and Storage Engineering Experience

Castillo Engineering has successfully completed over 1 GW of solar and storage engineering projects to date and has over 35 years of engineering experience, 25 of which have been dedicated to solar energy and energy storage engineering. Castillo Engineering’s team of over 20 senior level solar and storage engineers are well versed on the latest products due to the fact that the firm’s extensive customer base across the country utilizes a wide variety of solar and storage products.

Minimal Bill of Materials

As a result of several decades of solar and storage design and engineering experience, Castillo Engineering is uniquely able to minimize the number of materials needed for each project without compromising quality, resulting in drastically reduced project time and cost.

Industry Relationships

Castillo Engineering has and continues to maintain strong relationships with key individuals in all major areas related to construction, permitting, manufacturing and distribution, both on a local and national level. These relationships are often instrumental in securing permits faster, facilitating better communication and reducing the overall time needed to get complete projects. This ultimately saves EPCs and developers crucial time, funds and stress.

Fastest Turnaround Time

Castillo leads the market with the speed and accuracy of their designs. Castillo has reinvented the design process by utilizing in-house developed cutting edge design tools and project management software resulting in an extremely quick, industry leading, turnaround time.



The nation’s leading EPCs, Developers and Utilities continue to rely on Castillo Engineering’s market leading fast turnaround times, minimal bill of material designs and utility interconnection success to shorten their project duration and increasing profitability.

Castillo Engineering continues to maintain repeat client partners due to the fact that the firm not only completes projects efficiently and cost effectively, but because they have your long-term production interests in mind.

Our Utility-Scale Solar and Storage Construction Plans (IFCs) Include:

Solar Array Design

  • Array layout

  • Major equipment location 

  • Module stringing

  • Setbacks to include: 

    • Shading 

    • Equipment delivery pathways, laydowns, and turnarounds

    • O&M access and pathways

  • Integration of racking vendor’s drawings. 

  • Collaboration with appropriate engineering disciplines.


  • Equipment specification

  • Single line diagram  

  • Circuit routing   

  • Voltage drop

  • Conductor sizing   

  • Grounding and bonding  

  • Short circuit study

  • Arc flash study 

  • Surge arrester specification 


  • Equipment specification

  • System layout

  • Interconnection method 

  • Single line diagram

  • Feeder and branch circuit routing.

  • Voltage drop and conductor sizing


  • Point of interconnection 

  • Construction notes and specifications

  • Data and monitoring systems 



  • Interconnection design

  • Substation design (if applicable)

  • Equipment specification 

  • Short circuit study

  • Coordination studies

  • Arc flash study 

  • Relay settings 

  • Surge arrester specification


  • Review equipment spec sheets

  • Review soils report

  • Concrete pad design   

  • Skid foundation design

Other Services Include:


  • PVsyst Modeling

  • Owner’s Representative Site Observations

  • Site Visits (Pre, During, Post Construction)

  • Equipment Submittal Review

  • Independent Engineer Review

  • Interconnection Application Design & Support 

  • Racking Design Review

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