Derrick A. Jensen
Chief Financial Officer at Quanta Services
Thanks, Duke, and good morning, everyone. Today, we announced record first quarter revenues of $4 billion. Net income attributable to common stock was $85 million or $0.57 per diluted share and adjusted diluted earnings per share, a non-GAAP measure, was a record for the first quarter at $1.37. Our Electric Power revenues were $2.1 billion, a quarterly record and a 28% increase when compared to the first quarter of 2021. This increase was primarily due to growth in spending by our utility customers on grid modernization, resulting in increased demand for our electric power services as well as approximately $75 million in revenues attributable to acquired businesses. Electric segment operating income margins in 1Q '22 were 9.5%, a 30 basis point improvement compared to 9.2% in 1Q '21. However, margins were slightly impacted during the quarter for certain Canadian projects due to substantial COVID delays. That said, our U.S. electric operations continued to perform well, delivering another double-digit quarter. Also included within our Electric segment are our communications operations, which delivered mid-single-digit margins during the quarter and remain on track for upper single-digit margins for the year.
Renewable Energy Infrastructure segment revenues for 1Q '22 were $876 million, a substantial increase from 1Q '21 primarily due to $470 million in revenues attributable to acquired businesses. Operating income margins in 1Q '22 were 8%, in line with our expectations for the quarter but lower than the 11.8% in 1Q '21 due to the change in the mix of work as a result of the acquisitions and due to normal project variability. Underground Utility and Infrastructure segment revenues were $951 million for the quarter, 48% higher than 1Q '21, reflecting increased levels of activity across all of our segment operations. Operating income margins for the segment were 5.1%, 370 basis points higher than 1Q '21. The margin improvement was largely due to the increase in revenues and improved performance from our industrial operations, with COVID-related headwinds previously impacting these operations largely absent in this segment for 1Q '22. One below the line item I want to mention is our 1Q '22 other income and expense. As I mentioned last quarter, we hold an investment in a fixed wireless broadband technology provider that in March of 2022 became Starry Group Holdings, Inc., a publicly traded company, at which point our interest became a common equity interest in the publicly traded company.
We've remeasured the fair value of this investment based on the market price of the publicly traded company stock as of March 31, 2022, which resulted in the recognition of an unrealized loss of $8.4 million during the quarter. The value of this investment must be marked to market at each quarter end as long as this investment is held. On the non-GAAP adjusted earnings per share and adjusted EBITDA basis, we've removed the unrealized loss associated with this investment for the quarter and plan to continue adjusting our non-GAAP measures for mark-to-market volatility in future periods. Our total backlog was a record $20.5 billion at the end of the first quarter. Additionally, 12-month backlog of $11.5 billion also represents a quarterly record. Although backlog includes some nice project awards during the first quarter, our backlog growth continues to be driven primarily by multiyear MSA programs with North American utilities, which we believe reinforces the repeatable and sustainable nature of the largest portion of our revenues and earnings. As expected, for the first quarter of 2022, we had negative free cash flow, a non-GAAP measure of $16 million compared to $49 million of positive free cash flow in 1Q '21.
Net cash provided by operating activities during the first quarter of 2022 was lower due to higher revenues and corresponding increases in working capital demands compared to 1Q '21. Days sales outstanding, or DSO, measured 80 days for the first quarter of 2022, a decrease of nine days compared to the first quarter of 2021 and the same as year-end. The decrease from 1Q '21 was primarily due to the favorable impact of the acquisition of Blattner, which has traditionally had a lower DSO than certain of our other larger operating companies. This positive impact was partially offset by continued elevated working capital requirements associated with two large Canadian transmission projects driving an increase in contract assets, which we've discussed in prior quarters. Both projects were incrementally impacted by COVID during the first quarter, increasing our change order positions. In total, the amounts being pursued are currently impacting DSOs by as much as four to five days. However, one of those projects reached substantial completion during the first quarter, and we expect those contract assets to be built and collected over the remainder of the year.
As of March 31, 2022, we had total liquidity of approximately $2 billion and a debt-to-EBITDA ratio of 2.3 as calculated under our credit agreement. We expect continued earnings growth and cash generation to support our ability to efficiently delever over the following quarters while continuing to create shareholder value through our dividend and repurchase programs as well as strategic acquisitions. Through the date of this earnings release, we've acquired approximately $21 million worth of stock since the beginning of the year as part of our repurchase program, and we continue to evaluate potential acquisitions that fit our strategic objectives. Turning to guidance. I'm pleased with the start to our year and have little change to our overall expectations for 2022. We now expect Electric Power revenues to range between $8.3 billion and $8.4 billion with margin expectations unchanged, ranging between 10.7% and 11.3%. Similarly, we're increasing our Underground revenue expectations to range between $4.1 billion and $4.3 billion with margins expected to range between 6.5% and 7.5%, consistent with our previous expectations.
Our Renewables segment revenue and expectations are unchanged. However, with the uncertainty on project timing attributable to potential supply chain disruptions, we have widened our operating margin range a bit to 8.5% and 9%. We believe these dynamics are short term in nature and the opportunity to overcome them and deliver margins at our original 9% level and above continues to exist. Additionally, higher interest rates on our variable rate debt are resulting in increased interest expense for the year, which we now expect to range between $113 million and $117 million for the year. In the aggregate, our consolidated expectations for adjusted EPS and adjusted EBITDA remain unchanged for the year, reflecting the strength of our portfolio. For additional information, please refer to our outlook summary, which can be found in the Financial Info section of our IR website at quantaservices.com. From a long-term perspective, as we laid out in April at our Investor Day, the tailwinds behind our end markets and our industry-leading solutions present management with the opportunity to deliver significant shareholder value through organic growth and strategic capital deployment through 2026 and beyond.
And speaking of management, as we disclosed in today's additional release, I'm pleased to announce my planned transition from the role of Chief Financial Officer, to the new role of Executive Vice President of Business Operations. Transitioning into the role of Chief Financial Officer is Jayshree Desai. Jayshree has been a valuable partner to me and Duke and all of our leadership team since she joined the organization in 2020 and she is well suited to guide our financial organization going forward. It has been the highlight of my career to serve as Quanta's Chief Financial Officer over the last 10 years. As the longest standing employee of Quanta, I spent almost half my life helping to lead our financial organization and support our world-class operating leadership. I'm incredibly excited to continue supporting our strategic growth in a different capacity going forward. I'll now turn the call back over to Duke for closing remarks.