To estimate the FFO / Net Debt ratio for Fortum Oyj at the end of 2022, we need to calculate both the Funds From Operations (FFO) and the Net Debt for the fiscal year 2022 (from 2022-01-01 to 2023-01-01), and then take their ratio.

**1. Calculating Funds From Operations (FFO):**
A standard definition for FFO in corporate credit analysis (often used by agencies like Moody's) is: 
FFO = Profit Loss From Continuing Operations + Depreciation And Amortisation Expense + Other Non-cash Expenses (often adjusted for impairment losses).

From the provided facts for 2022:
- Profit Loss From Continuing Operations = 1,011,000,000 EUR
- Depreciation And Amortisation Expense = 566,000,000 EUR
- Impairment Loss Recognised In Profit Or Loss = 905,000,000 EUR (this is a non-cash expense that reduced the profit, so it should be added back to get the cash-generating capability of the operations).

FFO = 1,011,000,000 + 566,000,000 + 905,000,000 = 2,482,000,000 EUR.

**2. Calculating Net Debt:**
Net Debt = Total Financial Liabilities - Liquid Funds (Cash and Cash Equivalents).
Financial liabilities typically include non-current and current interest-bearing liabilities (Other Noncurrent Financial Liabilities, Other Current Financial Liabilities, and Margin Liabilities).

From the balance sheet as of 2023-01-01 (end of 2022):
- Other Noncurrent Financial Liabilities = 3,658,000,000 EUR
- Other Current Financial Liabilities = 4,127,000,000 EUR
- Margin Liabilities = 352,000,000 EUR
- Liquid Funds = 3,919,000,000 EUR

Total Financial Liabilities = 3,658,000,000 + 4,127,000,000 + 352,000,000 = 8,137,000,000 EUR.
Net Debt = 8,137,000,000 - 3,919,000,000 = 4,218,000,000 EUR.

*(Note: Derivative financial liabilities are excluded as they are generally not considered interest-bearing debt in Net Debt calculations, but if one were to include them, the Net Debt would be vastly higher, heavily skewing the ratio. The standard approach yields a meaningful leverage ratio).*

**3. Calculating the FFO / Net Debt Ratio:**
Ratio = FFO / Net Debt
Ratio = 2,482,000,000 / 4,218,000,000 ≈ 0.58862

<answer>0.59</answer>