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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

First-in-class project management of large-scale engineering 

Castillo Engineering is the only large-scale solar and storage design and engineering firm that is led by its Project Management Office (PMO). Certified by the Project Management Institute (PMI), all of the company’s Project Managers are highly trained and experienced in key project management subjects, including planning, execution, monitoring and controlling, communications, as well as cost, risk, quality, time and procurement management. The company’s expertise in project management ensures your projects are always completed on time and on budget and that you are apprised of all project updates.

Exceptional communication with all stakeholders 

Castillo Engineering delivers an extremely organized and collaborative partnership with all stakeholders to ensure the efficient and streamlined completion of each project. The company’s Project Managers are certified by the Project Management Institute (PMI) and deeply understand the value of clear and regular communication with all parties involved in a project. 

Track record of scaling while maintaining quality 

Castillo Engineering continues to be selected by the nation’s top EPCs, developers and utilities due in large part to its ability to scale without compromising project quality. The company has robust and vetted internal processes in place to ensure it continues to only hire staff that align with the company’s mission, vision and values. Once hired, staff are required to complete the company’s training program to ensure new team members have the skills and resources needed to maintain the same level of quality and excellence found at Castillo Engineering. 

Maintain deadlines

With over 25 years of experience in solar and storage design and engineering, Castillo Engineering understands that completing your project on time and on budget is critical. You can rely on Castillo Engineering and its Project Management Office (PMO) to meet all project deadlines, removing a major element of complexity from your project. 

Maximizing project value through innovation and practicality

Castillo Engineering approaches every project uniquely and as if it were the owner and EPC. The company does not take a conservative approach, however, it also does not take an aggressive approach to its design and calculations. Castillo Engineering takes a practical approach. The company’s team members ask themselves: if I owned this project, what decision would I make? The company is not afraid to try a new approach or technique, because it strips down the concepts to the practicality of physics. When Castillo Engineering puts its stamp on its plan sets, you know the company has done everything it can to ensure safety, cost savings, and longevity. The company will never say the word ‘no’ to a unique or requested design question. It will always take time to find a solution that meets your needs.


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 Battery Energy Storage System (BESS):

  • 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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