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

## Step 1: Calculate FFO (Funds From Operations) per S&P methodology

S&P's FFO starts with net income and adds back depreciation/amortization, then adjusts for other non-cash items. The key formula is:

**FFO = Net Income + Depreciation & Amortization + Other non-cash adjustments**

S&P also makes adjustments for operating leases (treating them as debt-like) and other items.

From the data:
- **Profit Loss (Net Income)**: 305,300,000 EUR (2022)
- **Depreciation & Amortization**: 478,600,000 EUR (from cash flow adjustments)
- **Deferred tax changes**: Deferred tax liabilities increased from 132,100 to 215,700 = +83,600M; Deferred tax assets increased from 229,400 to 240,400 = +11,000M. Net deferred tax change ≈ 83,600 - 11,000 = 72,600M (this represents non-cash tax expense, which we can add back partially)

S&P FFO ≈ Net Income + D&A + Deferred tax adjustments (non-cash)
- But more simply, S&P FFO is often approximated as: Cash from Operations + Interest Paid + Tax Paid - Interest Received - Non-cash items adjustments

Let me use the more standard approach:
**FFO ≈ Net Income + D&A + Amortization of debt costs/discounts**

FFO = 305,300 + 478,600 = 783,900M EUR

S&P also adds back operating lease depreciation (already in D&A) and adjusts for non-recurring items. Including lease adjustments:
- Operating lease payments (financing): 43,400M (lease liability payments)

**FFO ≈ 783,900 + 43,400 (lease add-back for interest portion, roughly) ≈ ~784M to 800M**

Let me keep FFO ≈ 784M EUR as a reasonable estimate.

## Step 2: Calculate Net Debt per S&P methodology

S&P Net Debt includes:
- Short-term borrowings: 650,100M
- Long-term borrowings: 5,689,900M
- Lease liabilities (current + non-current): 21,300 + 55,100 = 76,400M
- Less: Cash and cash equivalents: 1,942,400M
- Less: Surplus cash (S&P may adjust, but let's use reported cash)

**Gross Debt** = 650,100 + 5,689,900 + 76,400 = 6,416,400M EUR

**Net Debt** = 6,416,400 - 1,942,400 = 4,474,000M EUR

S&P may also add pension obligations (underfunded): 92,000M
- Adjusted Net Debt ≈ 4,474,000 + 92,000 = 4,566,000M EUR

## Step 3: Calculate FFO / Net Debt

FFO / Net Debt = 784,000 / 4,566,000 ≈ 0.1717 or ~17.2%

Let me refine: using a simpler approach without pension:
FFO / Net Debt = 784,000 / 4,474,000 ≈ 0.1752 or ~17.5%

Taking the midpoint estimate:

FFO / Net Debt ≈ 0.17

<answer>0.17</answer>