To estimate the Net Debt / EBITDA ratio for ERG S.p.A. for 2022 based on the S&P methodology, I will follow these steps:

**1. Determine EBITDA**
From the data, "Profit Loss From Operating Activities Before Interest Taxes Depreciation And Amortisation Expense" for 2022 is:
499,430,000 EUR

**2. Determine Net Debt under S&P methodology**
Net Debt = Total Debt - Cash and Cash Equivalents (with adjustments for operating leases, pensions, etc., per S&P).  
We are given "Noncurrent Financial Liabilities At Fair Value Through Profit Or Loss" (2023-01-01: -0.0), but we'll include all financial debt.  
From the balance sheet at the end of 2022 (2023-01-01):

- **Debt**:  
  - Other Noncurrent Financial Liabilities: 1,751,255,000 EUR (likely includes bonds, bank borrowings)  
  - Noncurrent Lease Liabilities: 150,955,000 EUR  
  - Current Financial Liabilities At Fair Value Through Profit Or Loss: 76,644,000 EUR  
  - Other Current Financial Liabilities: 389,716,000 EUR  
  - Current Lease Liabilities: 6,362,000 EUR  
Total Debt = 1,751,255,000 + 150,955,000 + 76,644,000 + 389,716,000 + 6,362,000 = 2,374,932,000 EUR

- **Cash and Cash Equivalents**:  
  Cash and Cash Equivalents: 392,811,000 EUR

- **Net Debt** = 2,374,932,000 - 392,811,000 = 1,982,121,000 EUR

**3. Compute Net Debt / EBITDA**
= 1,982,121,000 / 499,430,000 ≈ 3.968

The final ratio rounded to two decimals is 3.97.

<answer>3.97</answer>