To estimate the S&P-adjusted debt-to-EBITDA ratio for ERG S.P.A., we apply the standard S&P Global Ratings methodology, taking into consideration the guidelines for the Unregulated Power and Gas (renewable generation) industry. 

**Step 1: Estimate Adjusted EBITDA**
The baseline EBITDA is taken directly from the reported pre-D&A operating profit. For ERG S.P.A., the "Profit Loss From Operating Activities Before Interest Taxes Depreciation And Amortisation Expense" for continuing operations strictly measures the core operating activities. Since operating leases are already capitalized under IFRS 16 (indicated by the presence of lease liabilities and depreciation), no further lease adjustments to EBITDA are required. Discontinued operations are appropriately excluded for forward-looking credit metrics. 
* Reported EBITDA = 499,430,000 EUR
* **Adjusted_EBITDA = 499,430,000 EUR**

**Step 2: Estimate Adjusted Debt**
We calculate the adjusted debt by adding standard debt components and debt-like obligations, then deducting highly liquid eligible cash.

* **Reported Debt:** 
  * Other Noncurrent Financial Liabilities: 1,751,255,000 EUR
  * Other Current Financial Liabilities: 389,716,000 EUR
  * *Total Reported Debt = 2,140,971,000 EUR*
* **Lease Liabilities:**
  * Noncurrent Lease Liabilities: 150,955,000 EUR
  * Current Lease Liabilities: 6,362,000 EUR
  * *Total Leases = 157,317,000 EUR*
* **Pension Deficit:**
  * Noncurrent Provisions For Employee Benefits = 3,723,000 EUR
* **Other Debt-Like Items (Asset Retirement Obligations / Decommissioning):**
  * S&P specifically considers environmental, restoration, and decommissioning obligations as debt-like items for power generation companies.
  * Longterm Provision For Decommissioning Restoration And Rehabilitation Costs = 92,613,000 EUR
* **Eligible Cash:** 
  * We deduct reported Cash and Cash Equivalents (derivative assets and standard operational receivables are excluded from accessible cash). 
  * Cash and Cash Equivalents = 392,811,000 EUR

*Adjusted_Debt* = (2,140,971,000 + 157,317,000 + 3,723,000 + 92,613,000) - 392,811,000 
*Adjusted_Debt* = 2,394,624,000 - 392,811,000 = **2,001,813,000 EUR**

**Step 3: Calculate the Adjusted Debt / Adjusted EBITDA Ratio**
* Ratio = 2,001,813,000 EUR / 499,430,000 EUR = 4.00819...

<answer>4.01</answer>