To determine the extent to which REDEIA CORPORACION SA should utilize hybrid bonds relative to S&P Global Ratings' 15% cap, we must first calculate the company's total adjusted capital as of the end of 2022 (2023-01-01) and then determine the maximum allowable equity credit for hybrids.

1. **Calculate Total Adjusted Capital:**
Total adjusted capital is defined by S&P as Debt plus Equity.
- **Equity (Fondos Propios):** 4,826,318,000 EUR (from the balance sheet, or calculated as Equity Attributable to Owners + Noncontrolling Interests = 4,789,535,000 + 104,741,000 = 4,894,276,000 EUR. Using the reported Fondos Propios is standard for IFRS/Spanish GAAP transitions).
- **Debt (Financial Liabilities):** This includes both noncurrent and current financial liabilities.
  - Noncurrent Financial Liabilities: 5,543,755,000 EUR
  - Current Financial Liabilities: 1,705,277,000 EUR
  - Total Debt = 5,543,755,000 + 1,705,277,000 = 7,249,032,000 EUR
- **Total Adjusted Capital:** 4,826,318,000 (Equity) + 7,249,032,000 (Debt) = 12,075,350,000 EUR.

2. **Calculate the S&P Hybrid Cap:**
S&P limits the equity credit of hybrids to a maximum of 15% of total adjusted capital.
- 15% of 12,075,350,000 EUR = 1,811,302,500 EUR.

3. **Evaluate Existing Hybrids:**
To determine how much *additional* hybrid capacity the company has, we must check if it currently has any hybrid bonds that are consuming this cap. Hybrids are deeply subordinated instruments with equity-like features (perpetual or long-dated with interest deferral). Looking at the liabilities:
- Noncurrent Financial Liabilities consist of Long-term Borrowings (5,491,124,000) and Other Noncurrent Financial Liabilities (52,631,000). Derivative liabilities (22,016,000) are not hybrids.
- Current Financial Liabilities consist of Current Borrowings (721,845,000) and Other Current Financial Liabilities (983,432,000).
None of the balance sheet items reflect typical hybrid bond outstanding balances (which usually sit distinctly in noncurrent liabilities), and no hybrid instruments are noted in the equity changes or cash flow from financing activities (only standard share buybacks and straight debt issuance/repayment). Therefore, existing hybrids can be treated as 0 EUR.

4. **Assess the Utilization Extent:**
The question asks to what extent the company *should* utilize hybrid bonds *relative to* the 15% cap. In corporate finance and credit rating advisory, the extent to which a company should use its hybrid capacity depends on its capital intensity, business model stability, and the need to optimize its weighted average cost of capital (WACC) without risking a rating downgrade. 
REDEIA is a regulated utility (transmission system operator) with very stable, predictable cash flows and high capital expenditures (evidenced by over 9.6 billion in Property, Plant, and Equipment). Such companies are ideal candidates for hybrid bonds because their stable revenues safely support high leverage, and hybrids allow them to raise efficient, equity-like capital without diluting shareholders—effectively pushing the limit to optimize their capital structure. For high-grade utilities, fully utilizing the equity credit cap is a standard and aggressive (yet safe) capital optimization strategy. Given the massive cap (1.81 billion EUR) and zero existing hybrids, fully utilizing the allowable cap maximizes financial efficiency for a stable utility. Therefore, the company should aim to utilize 100% of its allowable limit.

<answer>100%</answer>