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Illinois Community Solar Land Rush: What Developers & EPCs Need to Know

Q&A with Castillo Engineering


Castillo Engineering has provided its design and engineering expertise in Illinois and New York for over 215 MW of community solar projects.

  • 25.4 MW with Amp in NY

  • 78 MW+ with SRE in IL

  • 75 MW with Solar Generation in NY

  • 38.25 MW with clearpath in NY


Community solar capacity in the U.S. is expected to double by 2027, according to Wood Mackenzie. Having grown 166 percent from 2021 to 2022 alone, Illinois is now ranked as the fourth largest U.S. state in terms of community solar operating capacity. Over the past two years, Castillo Engineering, a national design and engineering firm based in Florida, has seen its business in Illinois grow by less than ten projects in 2021, to becoming Castillo’s second largest and fastest growing market, due in large part to the firm’s work on the increasing number of community solar projects in the state. We recently spoke with Joe Jancauskas, Senior Electrical Engineer at Castillo Engineering about why the market is taking off now and what it takes for developers and EPCs to succeed in community solar in Illinois.


Why is the community solar market in Illinois taking off right now?

Joe: “Illinois is ranked 15th in the nation in terms of solar capacity and we have worked extensively in Illinois prior to this community solar land rush, as solar is by no means new to the state. However, the reason for the growth in community solar as of recent ties back to when the Illinois Legislature passed the Future Energy Jobs Act (FEJA) with bipartisan support in 2016. The legislation includes the Adjustable Block Program, which makes solar energy more accessible for low-to-moderate income communities through community solar projects, rooftop solar, and brownfield solar projects. The first community solar project was eventually completed in the state in 2019. By Q1 of 2021, 37% of the state’s current community solar operating capacity had been built, as the bulk of the state’s community solar projects became operational between Q2 of 2021 and Q4 of 2022. Given the state’s Illinois Shines community solar program, strong incentives, and growing awareness of these initiatives, EPCs and developers have been increasingly seeking out community solar projects within the state.”



What are some of the key challenges you’re facing with community solar projects in Illinois?

Joe: “The fact that the market is relatively new means that utilities are not always prepared for the influx of project requests they receive. The utilities’ review times can be considerable as well as highly unique until the gray area interpretations of the interconnect requirements are firmed up. You have to also layer on top of the utilities’ sometimes long wait times to review project requests on top of the inevitable inverter, module or racking changes due to supply chain issues. Sometimes the utility may deem these changes as ‘material changes,’ causing your project to be sent to the back of the queue.”


What are your top recommendations for developers and EPCs looking to get more involved with community solar projects in Illinois?

Joe: “Their largest pain point is going to be getting into the utility queue as early as possible. This is therefore my number one recommendation. Standardization and having a design template for project design will both expedite and minimize the costs for the engineering, construction and O&M. Securing portfolio-sized equipment orders is also every developer’s goal but has been quite the challenge lately. Another way to speed up the process to get into the utility queue is by leveraging design packages. We offer packages that enable our clients to execute projects in a way that plays to their strengths rather than a one-size-fits-all approach.”


Have you been able to leverage your experience on non-community solar projects in Illinois or community solar projects in other states in all of the community solar projects you have worked on in Illinois?

Joe: “Yes, our extensive prior experience in the state - from commercial rooftop systems to 20 MW ballasted ground mounts on landfills - has helped us develop relationships with the utilities and their processes and stringent requirements. Over the past few years, we have also significantly increased our work on community solar projects in New York. We completed three community solar project portfolios in New York in 2022 alone, totaling nearly 140 MW. Our work in New York has helped us develop internal standards to please very demanding electric utilities, such as those in Illinois.”


Can you share some specific examples of instances in which you supported EPCs or developers with overcoming community solar challenges in Illinois?

Joe: “We just had a project where the utility was ok with the Interconnection Drawing Set for a 5.0 MWac project. However, the utility also said to not connect at 13.2 kV, but instead on a nearby 69 kV line. We could spend the time drawing up that change, but the cost impact is obviously several orders of magnitude greater, so we were able to advise our client to take a second look and strongly consider passing on that project and focus elsewhere, saving a large amount of time and money in the process. To reiterate, it is absolutely essential to have a deep understanding of each utility’s unique requirements in order to succeed in the community solar market in Illinois in particular.”


If your team is looking for design and engineering support within the rapidly growing Illinois community solar market, contact one of Castillo Engineering’s experts.

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