To estimate the S&P-adjusted debt-to-EBITDA ratio for ERG S.P.A. in 2022, we follow the requested workflow.

### 1. Identify the Industry
ERG S.P.A. is a prominent player in the renewable energy sector (wind, solar, hydroelectric). Based on the provided S&P methodology, it falls under the **Unregulated Power and Gas** sector, as it is primarily a generator of renewable energy without the typical protective rate regulation of traditional utilities.

### 2. Estimate Adjusted Debt
We identify debt-like items from the 2022 (year-end 2022) balance sheet:
*   **Other Noncurrent Financial Liabilities:** 2,064,088,000 EUR
*   **Noncurrent Lease Liabilities:** 122,663,000 EUR
*   **Current Financial Liabilities At Fair Value Through Profit Or Loss:** 170,857,000 EUR
*   **Other Current Financial Liabilities:** 1,342,688,000 EUR
*   **Current Lease Liabilities:** 6,282,000 EUR
*   **Total Debt:** 2,064,088 + 122,663 + 170,857 + 1,342,688 + 6,282 = 3,706,578,000 EUR
*   **Eligible Cash:** Cash And Cash Equivalents (2022-01-01): 860,352,000 EUR
*   **Adjusted Debt:** 3,706,578,000 - 860,352,000 = **2,846,226,000 EUR**

### 3. Estimate Adjusted EBITDA
We use the "Profit Loss From Operating Activities Before Interest Taxes Depreciation And Amortisation Expense" (EBITDA) reported for 2022:
*   **Reported EBITDA:** 499,430,000 EUR
*   **Lease Adjustment:** Under S&P methodology, lease expenses are typically treated as operating expenses in the EBITDA calculation (the depreciation of the right-of-use asset and interest are removed from EBITDA). Since the reported EBITDA of 499.43M already excludes these (based on standard IFRS presentations used by ERG), no further modification is needed.
*   **Non-recurring items:** The impairment loss/reversal is already accounted for in operating profit. We see an "Impairment Loss Reversal" of 43,185,000 EUR. Adjustments for non-recurring gains/losses are standard. Given no explicit "non-recurring" label for these, we maintain the operating EBITDA.
*   **Adjusted EBITDA:** **499,430,000 EUR**

### 4. Calculate Adjusted Debt / Adjusted EBITDA
*   Ratio = 2,846,226,000 / 499,430,000
*   Ratio = 5.6989...

Rounding to two decimal places, we get 5.70.

<answer>5.70</answer>