Donald Brown
Executive Vice President/Chief Financial Officer and President, NiSource Corporate Services at NiSource
Thanks, Shawn, and good morning, everyone. I'd like to start with that we have moved the timing to hold an Investor Day event to this fall. We believe shifting the timing of our Investor Day will allow us to gain a clearer line of sight into the solar project timing and provide more details around the business review so that we can provide a definitive long-term plan beyond 2024. During this fall event, we intend to provide an extension to our capital investment and growth plan, a detailed update on our generation transition and ESG profile as well as give you an opportunity to hear from the leaders of our businesses.
Now turning to our first quarter 2022 results on Slide four. We had non-GAAP net operating earnings of about $329 million or $0.75 per diluted share compared to non-GAAP net operating earnings of about $305 million or $0.77 per diluted share in the first quarter of 2021. These first quarter 2022 results represent a solid start to the year. And as Lloyd mentioned a few minutes ago, we have reaffirmed our 2022 guidance of $1.42 to $1.48 in all of our long-term diluted non-GAAP net operating earnings per share growth rates.
Taking a closer look at our segment non-GAAP results on Slide five. Gas Distribution operating earnings were about $405 million for Q1 of 2022, representing an increase of approximately $31 million versus the same quarter last year. Operating revenues, net of the cost of energy and tracked expenses, were higher by approximately $66 million mainly due to new rates resulting from base rate cases and regulatory capital programs. Operating expenses, again, net of cost of energy and tracked expenses were higher by approximately $35 million.
In our Electric segment, non-GAAP operating earnings for the first quarter were about $99 million, which was about $8 million higher than 2021. Operating revenues, net of the cost of energy and tracked expenses increased by approximately $9 million due largely to revenue from regulated investments. And other operating expenses were essentially flat to 2021 levels. Now turning to Slide six. I'd like to briefly touch on our debt and credit profile. Our debt level as of March 31 was about $9.8 billion, of which $9.2 billion with long-term debt with a weighted average maturity of approximately 14 years and a weighted average interest rate of approximately 3.7%.
At the end of the first quarter, we maintained net available liquidity of about $1.9 billion, consisting of cash and available capacity under our credit facility and our accounts receivable securitization programs. We also continue our commitment to retaining our current investment-grade credit ratings. And I would note that Fitch has completed their 2022 annual credit review with no change to our rating or outlook. Our debt and credit profile continue to represent a solid financial foundation to support our long-term safety and infrastructure investments.
As you can see on Slide seven and eight, we are in the process of making some adjustments to our financial plan to reflect expected delays in solar generation projects that will help mitigate the earnings impact of these delays and enable us to maintain our 2024 EPS growth commitment. Both the long-term visibility of our capital plan and the flexibility in our regulatory mechanisms illustrates the resiliency and strength of our business and provides us confidence to maintain all of our commitments, including EPS growth.
Taking a quick look at Slide nine, which highlights our financing plan. The only slight change to our financing plan is to extend the potential timing related to the debt financing of the renewable generation investments, which, as we indicated on Slide eight, provides incremental interest savings to mitigate the renewable project delays. Again, this balanced financing plan is consistent with all of our earnings growth and credit commitments. Now I'll turn it over to Lloyd, who will discuss our utilities highlights.