To estimate the Net Debt / EBITDA ratio for ERG S.p.A. for the year 2022 according to standard S&P methodology, we first calculate the necessary components:

1. **EBITDA:** The provided facts explicitly state the "Profit Loss From Operating Activities Before Interest Taxes Depreciation And Amortisation Expense" for 2022 as 499,430,000 EUR.

2. **Net Debt:** S&P typically defines Net Debt as total financial debt (including current and non-current financial liabilities and lease liabilities) minus cash and cash equivalents and readily marketable securities.
   * **Total Debt:**
     * Noncurrent Financial Liabilities (Other): 2,064,088,000 EUR
     * Noncurrent Lease Liabilities: 122,663,000 EUR
     * Noncurrent Financial Liabilities at Fair Value: 44,763,000 EUR
     * Current Financial Liabilities at Fair Value: 170,857,000 EUR
     * Other Current Financial Liabilities: 1,342,688,000 EUR
     * Current Lease Liabilities: 6,282,000 EUR
     * *Total Gross Debt (2022)* = 2,064,088,000 + 122,663,000 + 44,763,000 + 170,857,000 + 1,342,688,000 + 6,282,000 = 3,751,341,000 EUR.
   * **Cash and Cash Equivalents:** 860,352,000 EUR.
   * **Financial Assets (often deducted in S&P analysis):** Current Financial Assets at Fair Value (154,154,000 EUR) and Other Current Financial Assets (424,282,000 EUR).
   * **Net Debt (2022):** 3,751,341,000 - 860,352,000 - 154,154,000 - 424,282,000 = 2,312,553,000 EUR.

3. **Ratio Calculation:**
   * Net Debt / EBITDA = 2,312,553,000 / 499,430,000 ≈ 4.630

(Note: Using the 2022 balance sheet figures representing the state at the end of the year 2022, corresponding to 2023-01-01 status, the calculation would yield a significantly different result due to the large disposal of assets; however, standard practice uses the year-end figures for the period being analyzed.)

<answer>4.63</answer>