I'll estimate the FFO / Net Debt ratio for ACEA S.P.A. for 2022 using S&P methodology.

## Step 1: Calculate FFO (Funds From Operations)

S&P's FFO starts with net income attributable to the company, then adds back depreciation & amortization, and makes adjustments for non-cash items and deferred taxes.

**Key components:**

- **Net Income (Profit/Loss):** €311,160,000 (2022)
- **Depreciation & Amortization:** €594,636,000 (from cash flow adjustments)
- **Impairment losses:** €67,680,000 (from cash flow adjustments)
- **Net interest expense (finance costs - finance income):** €111,670,000 - €25,962,000 = €85,708,000 (matches "Adjustments for Finance Costs" in cash flow)
- **Interest paid:** €114,121,000
- **Income tax expense:** €186,777,000
- **Income taxes paid:** €178,506,000

**S&P FFO approximation:**
FFO ≈ Net Income + D&A + Impairment + Non-cash items - Working capital changes (essentially cash from operations before working capital changes, minus interest paid, minus taxes paid, with some adjustments)

More directly, S&P FFO can be approximated as:
- Cash flows from operations before working capital: €1,062,464,000
- Less: Interest paid: €114,121,000
- Less: Taxes paid: €178,506,000
- This gives approximately: €1,062,464,000 - €114,121,000 - €178,506,000 = €769,837,000

But looking at the cash flow structure, the "Cash Flows From Used In Operations Before Changes In Working Capital" of €1,062,464,000 already includes adjustments for finance costs (€85,708,000) and taxes (€178,506,000). So I need to adjust:

FFO ≈ Cash from operations before WC changes - Interest paid + Finance costs adjustment - Taxes paid + Tax adjustment
= €1,062,464,000 - €114,121,000 + €85,708,000 - €178,506,000 + €178,506,000
= Actually, let me use: FFO = Operating Cash Flow + Working Capital Changes back = €726,703,000 + €125,490,000 = €852,193,000... No.

**Simpler S&P approach:**
FFO = Cash from Operations before WC - Cash interest paid - Cash taxes paid
= €1,062,464,000 - €114,121,000 - €178,506,000 = €769,837,000

But the €1,062,464,000 already deducts book interest (€85,708,000) and book taxes (€178,506,000). So:

FFO = €1,062,464,000 + €85,708,000 + €178,506,000 - €114,121,000 - €178,506,000
= €1,034,051,000

## Step 2: Calculate Net Debt

**Gross Debt:**
- Non-current financial liabilities: €4,722,263,000
- Current financial liabilities: €619,418,000
- Total Gross Debt: €5,341,681,000

**Cash and equivalents:** €559,908,000

**Net Debt = Gross Debt - Cash**
= €5,341,681,000 - €559,908,000 = €4,781,773,000

S&P typically includes lease liabilities (right-of-use assets suggest lease obligations). The ROU assets are €90,397,000, so lease liabilities are roughly similar but likely already included in financial liabilities.

## Step 3: FFO / Net Debt

FFO / Net Debt = €1,034,051,000 / €4,781,773,000 ≈ 0.2162 or ~21.6%

Let me reconsider - a simpler approach: FFO ≈ operating cash flow before WC changes minus cash interest minus cash taxes:

= €1,062,464,000 - €114,121,000 - €178,506,000 = €769,837,000

FFO/Net Debt = €769,837,000 / €4,781,773,000 ≈ 0.161 or ~16.1%

Given S&P methodology typically adds back interest to the pre-WC figure then subtracts cash interest:

FFO = €769,837,000 + €85,708,000 = €855,545,000... 

Using the most standard approach: FFO/Net Debt ≈ 769,837/4,781,773 ≈ 0.161

<answer>0.16</answer>