To estimate the FFO / Net debt ratio for 2022, we first need to calculate the Funds From Operations (FFO) and the Net Debt for the year 2022 based on the provided annual report data for TenneT Holding B.V.

**1. Calculating Funds From Operations (FFO):**
According to standard financial definitions (such as Moody's), FFO is calculated as:
FFO = Profit/Loss + Depreciation & Amortisation + Other Non-cash Items (excluding changes in working capital)
From the cash flow statement adjustments for 2022 (ending 2023-01-01):
- Profit Loss: -879,000,000 EUR
- Adjustments For Depreciation And Amortisation Expense: 1,233,000,000 EUR
- Adjustments For Provisions: 104,000,000 EUR
- Other Adjustments For Noncash Items: 1,347,000,000 EUR
- Adjustments For Undistributed Profits Of Investments Accounted For Using Equity Method: -120,000,000 EUR (This reverses the share of profit/loss already included in Profit/Loss. The actual cash received is listed separately as 92,000,000 EUR, so we reverse the accrual of 120M)

Adding these components:
FFO = -879,000,000 + 1,233,000,000 + 104,000,000 + 1,347,000,000 - 120,000,000 = 1,685,000,000 EUR.

*(Note: If we simply look at the Cash Flows From Used In Operations Excluding Eeg Working Capital + Income Taxes Paid, we get 596,000,000 + 231,000,000 = 827,000,000 EUR before working capital changes and tax, but the FFO definition explicitly relies on the sum of Net Income, D&A, and other non-cash adjustments which equals 1,685,000,000 EUR)*

**2. Calculating Net Debt:**
Net Debt = Total Financial Debt - Cash & Cash Equivalents
Total Financial Debt typically includes Long-term Borrowings, Short-term Borrowings, and Current Bank Overdrafts.
From the balance sheet at the end of 2022 (2023-01-01):
- Longterm Borrowings: 19,006,000,000 EUR
- Shortterm Borrowings: 709,000,000 EUR
- Current Bank Overdrafts: 0 EUR
Total Financial Debt = 19,006,000,000 + 709,000,000 + 0 = 19,715,000,000 EUR.

Cash and Cash Equivalents at 2023-01-01: 6,547,000,000 EUR.

Net Debt = 19,715,000,000 - 6,547,000,000 = 13,168,000,000 EUR.

**3. Calculating the Ratio:**
FFO / Net Debt = 1,685,000,000 / 13,168,000,000 ≈ 0.1279599...

Rounded to four decimal places, the ratio is 0.1280.

<answer>0.1280</answer>