To evaluate the extent to which Redeia Corporación S.A. should rely on hybrid bonds, we consider the company's financial profile and the interest rate environment.

1.  **Capital Structure and Leverage:** As of the end of 2022, Redeia has a robust capital structure. Equity (Total) is approximately 4.89 billion EUR, while Long-term Borrowings are approximately 5.49 billion EUR. The company maintains a high level of tangible assets (Property, Plant, and Equipment: ~9.6 billion EUR).
2.  **Financial Stability:** The company maintains consistent profitability (Profit Attributable to Owners: 664.7 million EUR in 2022) and strong cash flow from operating activities (~1.57 billion EUR).
3.  **Cost of Debt Environment:** The market data shows a significant increase in interest rates between 2021 and 2022. The 10Y Swap rate rose from 0.053% in 2021 to 1.927% in 2022. Similarly, corporate bond yields (iShares Core Euro Corp Bond) increased from 0.733% to 1.085%.
4.  **Use of Hybrid Bonds:** Hybrid bonds (often treated as equity for rating agency purposes but debt for tax purposes) are typically used by companies to bolster their credit ratings or manage leverage ratios when traditional debt becomes too expensive or would jeopardize the company's credit rating. Given Redeia’s solid, stable asset base, essential infrastructure role, and consistent ability to generate operating cash flows, the company does not currently face an existential need for aggressive capital structure restructuring or high-leverage mitigation via hybrid instruments. Relying too heavily on hybrids would introduce unnecessary interest rate risk and higher cost of capital compared to traditional senior debt, which is well-supported by the company's asset-heavy balance sheet. 
5.  **Recommendation:** A conservative, moderate approach is appropriate. While some hybrid component can optimize the cost of capital, the company's current financial health suggests that a low reliance on hybrids is sufficient to maintain its investment-grade status. Therefore, 0% is the most appropriate recommendation given the company’s strong standing and the current cost of debt environment which makes simpler, lower-cost financing structures preferable.

<answer>0%</answer>