To estimate the Net Debt / EBITDA ratio for A2A ENERGIA S.P.A. for the year 2022 (period ending 2023-01-01) using the S&P methodology, we need to determine two components: Adjusted EBITDA and Net Debt.

**1. Determine EBITDA**
The report explicitly provides "Gross Operating Income EBITDA" for the period 2022-01-01 to 2023-01-01.
*   **EBITDA**: 1,505,000,000 EUR

*Note: S&P often uses "Operating EBITDA" or makes adjustments for non-recurring items. The report shows "Result From Nonrecurring Transactions" of 157,000,000 EUR. However, standard EBITDA figures provided in annual reports are often the starting point. S&P methodology typically adds back non-recurring items to EBITDA if they are excluded from the reported EBITDA, or uses Reported EBITDA if it already reflects operational performance. Given the line item "Gross Operating Income EBITDA", we will use this figure. If we were to calculate EBITDA from scratch: Revenue (23,166) - Operating Expense (20,896) + Depreciation/Amortization (818) = 3,088? No, Operating Expense usually includes D&A in some formats or excludes it. Let's look at the provided EBITDA: 1,505. Let's check: Revenue (23,166) - Raw Materials (20,502) - Other Expense (394) - Employee Benefits (765) = 1,505. This matches exactly. So the reported EBITDA is 1,505,000,000 EUR.*

**2. Determine Net Debt**
S&P defines Net Debt as Total Debt minus Cash and Cash Equivalents (and sometimes other liquid assets). Total Debt includes short-term and long-term interest-bearing debt.

*   **Cash and Cash Equivalents**:
    *   From the balance sheet at 2023-01-01: 2,584,000,000 EUR.

*   **Total Debt (Interest-Bearing Liabilities)**:
    We need to identify financial liabilities.
    *   **Noncurrent Financial Liabilities**:
        *   "Other Noncurrent Financial Liabilities": 5,867,000,000 EUR.
    *   **Current Financial Liabilities**:
        *   "Other Current Financial Liabilities": 1,022,000,000 EUR.
    
    *Note: "Trade And Other Current Payables To Trade Suppliers" and "Other Current Nonfinancial Liabilities" are generally operating liabilities, not debt. "Current Tax Liabilities" are also operating.*

    *   **Total Gross Debt** = Noncurrent Financial Liabilities + Current Financial Liabilities
    *   Total Gross Debt = 5,867,000,000 + 1,022,000,000 = 6,889,000,000 EUR.

*   **Net Debt Calculation**:
    *   Net Debt = Total Gross Debt - Cash and Cash Equivalents
    *   Net Debt = 6,889,000,000 - 2,584,000,000 = 4,305,000,000 EUR.

    *Self-Correction/Refinement based on S&P Methodology*: S&P often looks at "Total Debt" which might include lease liabilities. The cash flow statement shows "Payments Of Lease Liabilities Classified As Financing Activities" of 11,000,000 EUR. This suggests lease liabilities are treated as debt. However, the balance sheet lines "Other Noncurrent Financial Liabilities" and "Other Current Financial Liabilities" likely encompass interest-bearing debt including leases if classified as such. Without a specific breakdown of leases within those lines, we use the reported financial liabilities.

    Let's double-check if there are other debt components.
    The "Total Changes In Financial Liabilities" in financing activities is 1,503,000,000.
    Proceeds from borrowings: 4,339,000,000.
    Repayments: 2,779,000,000.
    Net change from borrowings: 1,560,000,000.
    Other changes: -46,000,000.
    Lease payments: 11,000,000.
    This aligns roughly with the balance sheet movement.
    
    Let's verify the debt components again.
    Noncurrent Liabilities: 7,214,000,000.
    Breakdown:
    - Other Noncurrent Financial Liabilities: 5,867,000,000
    - Noncurrent Provisions For Employee Benefits: 248,000,000 (Not debt)
    - Other Longterm Provisions: 729,000,000 (Not debt)
    - Other Noncurrent Liabilities: 370,000,000 (Likely operating/non-financial)
    
    Current Liabilities: 9,686,000,000.
    Breakdown:
    - Trade Payables: 5,524,000,000 (Not debt)
    - Other Current Nonfinancial Liabilities: 3,006,000,000 (Not debt)
    - Other Current Financial Liabilities: 1,022,000,000 (Debt)
    - Current Tax Liabilities: 134,000,000 (Not debt)

    So, Gross Debt = 5,867 + 1,022 = 6,889 million EUR.
    Cash = 2,584 million EUR.
    Net Debt = 6,889 - 2,584 = 4,305 million EUR.

**3. Calculate Ratio**
*   Net Debt: 4,305,000,000 EUR
*   EBITDA: 1,505,000,000 EUR
*   Ratio = 4,305 / 1,505 ≈ 2.8604

Rounding to two decimal places, the ratio is 2.86.

<answer>2.86</answer>