To estimate the FFO / Net Debt ratio for Acea S.p.A. for the year 2022 based on S&P methodology, we need to calculate Funds From Operations (FFO) and Net Debt.

**1. Calculate Funds From Operations (FFO)**

According to S&P Global Ratings methodology, FFO is generally calculated as:
$$FFO = \text{Net Income} + \text{Depreciation and Amortization} + \text{Other Non-Cash Items} + \text{Changes in Working Capital (sometimes excluded in simple definitions, but S&P often uses EBITDA-based or Cash Flow from Operations based adjustments)}$$

However, a more standard S&P definition for industrial/utilities is:
$$FFO = \text{Net Income} + \text{Depreciation} + \text{Amortization} + \text{Impairment Charges} - \text{Gains on Asset Sales} + \text{Other Non-Cash Adjustments}$$

Let's extract the relevant data for 2022 (period 2022-01-01 to 2023-01-01):

*   **Net Income (Profit Loss):** 311,160,000 EUR
*   **Depreciation and Amortization:** The report lists "Ammortamenti E Accantonamenti" (Amortization and Provisions) as 625,799,000 EUR. It also lists "Adjustments For Depreciation And Amortisation Expense" in the cash flow statement as 594,636,000 EUR. Usually, FFO adds back D&A. Let's look for a specific D&A line. "Ammortamenti E Accantonamenti" likely includes provisions. The Cash Flow adjustment "Adjustments For Depreciation And Amortisation Expense" is 594,636,000 EUR. There is also "Adjustments For Impairment Loss..." of 67,680,000 EUR.
    *   Let's check the composition of "Ammortamenti E Accantonamenti" (625,799,000).
    *   Cash Flow from Operations starts with Profit/Loss from Operating Activities (565,851,000) or Net Profit? The cash flow statement provided seems to start adjustments from Operating Profit or similar.
    *   Let's use the standard proxy: **EBITDA - Taxes - Interest - Changes in Working Capital**? No, S&P FFO is closer to Net Income + D&A.
    *   Let's use: **Net Income + Depreciation & Amortization + Impairment**.
    *   Net Income: 311,160,000 EUR.
    *   Depreciation & Amortization: The line "Adjustments For Depreciation And Amortisation Expense" is 594,636,000 EUR.
    *   Impairment: "Adjustments For Impairment Loss Reversal Of Impairment Loss Recognised In Profit Or Loss" is 67,680,000 EUR. Note that the P&L shows "Impairment Loss... IFRS9" of 113,370,000 EUR. The cash flow adjustment is lower, possibly due to reversals or non-cash vs cash distinctions. S&P typically adds back impairment charges. Let's add back the P&L impairment charge if it was deducted.
    *   However, a simpler and often more robust S&P proxy for FFO when detailed breakdowns are complex is: **Cash Flow from Operations (CFO) + Cash Interest Paid + Cash Taxes Paid**? Or **EBITDA - Cash Interest - Cash Taxes**?
    *   S&P defines FFO as net income plus depreciation, amortization, and other non-cash items. It does *not* typically subtract changes in working capital (that's CFO).
    *   Let's calculate FFO as: **Net Income + D&A + Impairment**.
        *   Net Income: 311,160,000
        *   D&A (from CF adjustments): 594,636,000
        *   Impairment (from CF adjustments): 67,680,000
        *   Other non-cash items? "Share Of Profit Loss Of Associates..." is 17,793,000 (non-cash equity pickup, should be subtracted if included in Net Income but not received as cash? S&P usually subtracts equity income not received in dividends).
        *   Let's refine:
            *   Start with Net Income: 311,160,000
            *   Add D&A: 594,636,000
            *   Add Impairment: 67,680,000 (This is the adjustment in CF, likely the non-cash portion or net change).
            *   Subtract Equity Income (non-cash): 17,793,000 (Share of profit of associates).
            *   Add/Subtract other non-cash? "Gains Losses On Change In Fair Value..." is 0.
            *   FFO Estimate = 311,160,000 + 594,636,000 + 67,680,000 - 17,793,000 = **955,683,000 EUR**.

    *   Alternative Calculation using EBITDA:
        *   EBITDA = Operating Profit + D&A + Impairment?
        *   Operating Profit (Profit Loss From Operating Activities): 565,851,000.
        *   Add D&A: 594,636,000.
        *   Add Impairment (IFRS9): 113,370,000.
        *   EBITDA ≈ 565,851,000 + 594,636,000 + 113,370,000 = 1,273,857,000.
        *   FFO = EBITDA - Cash Interest - Cash Taxes - Preferred Dividends?
        *   Cash Interest Paid: 114,121,000.
        *   Cash Taxes Paid: 178,506,000.
        *   FFO = 1,273,857,000 - 114,121,000 - 178,506,000 = **981,230,000 EUR**.

    Let's check the difference. The first method gave ~955M, the second ~981M. The difference lies in the treatment of impairment (113M in P&L vs 67M in CF adj) and equity income.
    S&P often uses **FFO = Net Income + Depreciation + Amortization + Impairment + Deferred Taxes + Other Non-Cash Items**.
    Let's stick to the Net Income base:
    Net Income: 311,160,000
    + D&A: 594,636,000
    + Impairment (P&L): 113,370,000 (Assuming this is the full charge added back)
    - Equity Income (non-cash): 17,793,000
    + Deferred Tax? Income Tax Expense (186,777,000) vs Cash Tax (178,506,000). Diff is ~8.2M. Deferred tax is a non-cash item. If tax expense is higher than cash, we add back the difference? No, Net Income already deducted the expense. We add back non-cash expenses. Deferred tax expense is non-cash. So add back 8,271,000.
    FFO = 311,160,000 + 594,636,000 + 113,370,000 - 17,793,000 + 8,271,000 = **1,009,644,000 EUR**.

    Let's try one more common S&P simplification for utilities: **CFO + Cash Interest + Cash Taxes**.
    CFO (Cash Flows From Used In Operating Activities): 726,703,000.
    + Cash Interest Paid: 114,121,000.
    + Cash Taxes Paid: 178,506,000.
    FFO Proxy = 726,703,000 + 114,121,000 + 178,506,000 = **1,019,330,000 EUR**.

    This last figure (1,019M) is very close to the 1,009M figure. We will use **1,019,330,000 EUR** as a robust estimate for FFO.

**2. Calculate Net Debt**

Net Debt = Gross Debt - Cash and Cash Equivalents.

*   **Gross Debt:**
    *   Other Noncurrent Financial Liabilities: 4,722,263,000 EUR
    *   Other Current Financial Liabilities: 619,418,000 EUR
    *   Total Gross Debt = 4,722,263,000 + 619,418,000 = **5,341,681,000 EUR**.
    *   *Note: Check for lease liabilities.* "Right-of-use Assets" are 90,397,000. S&P typically includes lease liabilities in debt. The liability side isn't explicitly broken out as "Lease Liabilities", but they are often embedded in "Other Noncurrent/Current Financial Liabilities" or "Other Noncurrent/Current Liabilities". Given the magnitude of "Other Noncurrent Financial Liabilities" (4.7B), it likely contains bonds and loans. Without explicit lease liability data, we assume the reported financial liabilities capture the interest-bearing debt. S&P might adjust for leases, but without specific data, we use reported financial debt.

*   **Cash and Cash Equivalents:**
    *   "Disponibilità Liquide E Mezzi Equivalenti Alla Fine Dellesercizio Continued Operations": 559,908,000 EUR.
    *   There is also "Current Assets Other Than Assets... Held For Sale" which might contain cash? No, the line "Disponibilità..." is the specific cash line.
    *   Cash = **559,908,000 EUR**.

*   **Net Debt:**
    *   Net Debt = 5,341,681,000 - 559,908,000 = **4,781,773,000 EUR**.

**3. Calculate FFO / Net Debt Ratio**

*   FFO = 1,019,330,000 EUR
*   Net Debt = 4,781,773,000 EUR
*   Ratio = 1,019,330,000 / 4,781,773,000 ≈ **0.213**

Let's double check with the lower FFO estimate (955M) to see the range.
955,683,000 / 4,781,773,000 ≈ 0.20.

Let's double check the Debt.
Are there other debt items?
"Noncurrent Contract Liabilities" are 5.4B. These are deferred revenues/unearned revenue, not financial debt.
"Trade And Other Current Payables" are operational.
So Financial Debt is correctly identified as Noncurrent + Current Financial Liabilities.

Let's refine the FFO calculation using the exact S&P definition components often found in Italian utility reports:
S&P FFO = Net Income + D&A + Impairment + Deferred Tax + (Equity Income subtracted) + (Minority Interest added back if consolidated net income is used? No, Net Income is attributable to owners usually, but here "Profit Loss" is 311M, which is total. "Profit Loss Attributable To Owners" is 279M. S&P usually uses Consolidated Net Income including non-controlling interests for the numerator if the denominator (Debt) is consolidated. The Debt is consolidated. So we should use Total Net Income (311M) or adjust FFO to be consistent.
Actually, standard FFO starts with Consolidated Net Income.
Consolidated Net Income = 311,160,000.
Add: D&A (594,636,000).
Add: Impairment (113,370,000).
Less: Equity Income (17,793,000).
Add: Deferred Tax Expense (Tax Expense 186,777,000 - Cash Tax 178,506,000 = 8,271,000).
FFO = 311,160,000 + 594,636,000 + 113,370,000 - 17,793,000 + 8,271,000 = 1,009,644,000.

Ratio = 1,009,644,000 / 4,781,773,000 = 0.2111.

If we use the CFO + Interest + Taxes method (which implicitly handles working capital changes and other items):
CFO = 726,703,000.
Interest Paid = 114,121,000.
Taxes Paid = 178,506,000.
Sum = 1,019,330,000.
Ratio = 1,019,330,000 / 4,781,773,000 = 0.2131.

Both methods yield approximately 0.21.

Let's check if "Other Noncurrent Financial Liabilities" includes leases. If it does, no adjustment needed. If it doesn't, we might be underestimating debt. However, "Right of Use Assets" are only 90M. Even if we add 90M to debt, Net Debt becomes ~4.87B. Ratio becomes ~0.209. The impact is small.

Let's check if there is any "Net Debt" definition nuance. S&P sometimes deducts unrestricted cash. The cash reported is 559M. Are there restricted cash components? "Disponibilità Monetaria Netta" is reported as 559,908,000 in 2023 and 693,193,000 in 2022 (start of year). The report provides "Disponibilità Liquide... End of Exercise" as 559,908,000. This matches.

Final Calculation:
FFO ≈ 1,019,330,000 EUR
Net Debt ≈ 4,781,773,000 EUR
Ratio ≈ 0.213

Rounding to two decimal places, it is 0.21.

<answer>0.21</answer>