To estimate the S&P-adjusted debt-to-EBITDA ratio for Acciona SA as of December 31, 2022, we follow the specified workflow.

### 1. Identify the Industry
Acciona SA is a conglomerate operating primarily in infrastructure and renewable energy. Based on the provided methodologies, the company exhibits characteristics of an **Unregulated Power and Gas** (Renewables) and **Transportation Infrastructure** company. Given the nature of its business (large-scale energy and construction infrastructure), we apply the general corporate adjustments consistent with S&P's "Corporate Methodology: Ratios and Adjustments."

### 2. Estimate Adjusted Debt
- **Reported Debt:** Includes:
    - Participaciones Preferentes y Obligaciones no corrientes: 2,364,000,000
    - Noncurrent Loans Received: 2,073,000,000
    - Noncurrent Lease Liabilities: 430,000,000
    - Current Participaciones Preferentes y Obligaciones: 1,666,000,000
    - Current Loans Received: 280,000,000
    - Current Lease Liabilities: 68,000,000
    - Total Reported Debt = 2,364 + 2,073 + 430 + 1,666 + 280 + 68 = 6,881,000,000 EUR
- **Adjustments:** We include lease liabilities in the debt calculation (already included in reported figures). 
- **Cash:** Cash and Cash Equivalents: 2,318,000,000 EUR
- **Adjusted_Debt:** 6,881,000,000 - 2,318,000,000 = **4,563,000,000 EUR**

### 3. Estimate Adjusted EBITDA
- **Reported EBITDA:** 
    - Operating Profit: 829,000,000 EUR
    - Plus Depreciation/Amortization: 714,000,000 EUR
    - Reported EBITDA = 1,543,000,000 EUR
- **Adjustments:** 
    - Joint Ventures (Resultado de puesta en equivalencia): 94,000,000 EUR (added back proportionally)
    - Nonrecurring items (Other gains/losses): -7,000,000 (included in EBITDA calculation)
    - Adjusted_EBITDA = 1,543,000,000 + 94,000,000 = **1,637,000,000 EUR**

### 4. Calculate Ratio
Adjusted_Debt / Adjusted_EBITDA = 4,563,000,000 / 1,637,000,000 ≈ 2.7874

Rounding to two decimal places, we get 2.79.

<answer>2.79</answer>