To estimate the Funds From Operations (FFO) to Net Debt ratio for A2A S.p.A. at the end of 2022 based on S&P Global Ratings methodology, we follow their standard adjustments:

**1. Calculate Funds From Operations (FFO):**
S&P generally calculates FFO starting from reported EBITDA, subtracting net interest expense and cash taxes paid. 
- **Reported EBITDA** ("Gross Operating Income EBITDA"): €1,505 million
- **Cash Interest Paid** ("Interest Paid Classified As Operating Activities"): €75 million
- **Cash Taxes Paid** ("Income Taxes Paid Refund Classified As Operating Activities"): €201 million

*Note: The €512 million "Other Adjustments For Noncash Items" shown in the cash flow statement largely reflects mark-to-market swings on energy derivatives. S&P typically reclassifies these unrealized fair value changes into working capital rather than deducting them from core FFO to reflect the true recurring cash generation.*
- **FFO** = €1,505m - €75m - €201m = **€1,229 million**

**2. Calculate S&P Adjusted Net Debt:**
S&P adjusts reported net financial debt by adding obligations like underfunded pensions and sometimes asset retirement obligations, while only deducting highly liquid accessible cash.
- **Gross Financial Debt** = "Other Noncurrent Financial Liabilities" (€5,867m) + "Other Current Financial Liabilities" (€1,022m) = €6,889 million
- **Less Cash** = "Cash And Cash Equivalents" (€2,584m)
- **Base Net Debt** = €6,889m - €2,584m = €4,305 million
- **Plus Pension Obligations** = "Noncurrent Provisions For Employee Benefits" (€248m)
- **S&P Adjusted Net Debt** = €4,305m + €248m = **€4,553 million**

**3. Calculate FFO / Net Debt:**
- **FFO / Net Debt** = €1,229 million / €4,553 million ≈ 0.2699 (or 27.0%)

<answer>0.27</answer>