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Top-tier engineering & design for energy storage projects

With over 1 GW of projects completed since 1998, Castillo Engineering has been, and remains, committed to creating a more sustainable future for all through utility-scale solar and energy storage systems. Castillo Engineering has grown to become the leading design and engineering firm in the United States for high quality utility-scale solar and energy storage projects as a result of the firm’s vast engineering experience, minimal bill of material designs, fast turnaround times, and strong industry relationships.

Our energy storage systems have been constructed across the nation. Projects include:

  • Department of Defense  

  • Existing power plants

  • Landfills

  • Urban locations

  • Rural locations

  • Commercial & Industrial applications

  • Microgrids

  • Both DC and AC coupled

Schedule a meeting with one of our solar and storage experts

Solar and Storage Engineering Experience

Castillo Engineering has successfully completed over 10,000 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.


Most utility-scale battery storage systems perform several roles depending on system operation requirements and available revenue opportunities in specific markets. Frequency regulation remains the most common use for utility-scale batteries, but other uses are becoming more common as more batteries are added to the U.S. electric grid. From military bases to landfills to existing power plants, Castillo Engineering has provided its design and engineering expertise on a wide array of energy storage projects with applications that include, but are not limited to, the following:

  • Frequency regulation

  • Ramping reserve 

  • Load following

  • Excess solar generation  

  • System peak shaving 

  • Energy arbitrage 

Energy storage design and engineering services & support include:

Full Service In-House Engineering Team

  • Expert team of over 20 senior level engineers

  • Advanced storage simulation modeling to enable EPCs and developers to optimize energy storage assets

  • Experienced in sizing and designing standalone storage, microgrids and solar + storage systems

  • Well versed in executing both DC and AC coupled systems in myriad utility territories throughout the U.S.


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 Energy Storage Construction Plans (IFCs) Include:


  • Equipment specification

  • System layout

  • Interconnection method 

  • Single line diagram

  • Feeder and branch circuit routing.

  • Voltage drop and conductor sizing

Other BESS Services Include:


  • BESS System Sizing

  • Owner’s Representative Site Observations

  • Site Visits (Pre, During, Post Construction)

  • Equipment Submittal Review

  • Independent Engineer Review

  • Interconnection Application Design & Support

  • Equipment Pad Design

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