To determine the extent to which ENGIE should utilize hybrid bonds relative to S&P Global Ratings' cap, we first need to understand the company's financial structure and the definition of total adjusted capital.

1. **Calculate Total Adjusted Capital (TAC):**
According to S&P's methodology, TAC is defined as Debt plus Equity.
From the 2022 balance sheet:
- Total Equity (including noncontrolling interests) = 39,285 million EUR
- Total Financial Debt = Long-term borrowings + Current borrowings and current portion of noncurrent borrowings
  - Long-term borrowings = 28,083 million EUR
  - Current borrowings = 12,508 million EUR
  - Total Financial Debt = 28,083 + 12,508 = 40,591 million EUR
- Total Adjusted Capital = Equity + Debt = 39,285 + 40,591 = 79,876 million EUR

2. **Calculate S&P's Maximum Equity Credit Cap:**
S&P limits the equity credit on hybrids to a maximum of 15% of TAC.
- Maximum Cap = 15% of 79,876 million EUR = 11,981.4 million EUR

3. **Evaluate Existing Hybrid Equity:**
ENGIE has "Deeply Subordinated Perpetual Notes" listed in its equity section. Under S&P criteria, deeply subordinated perpetual notes typically qualify as hybrid instruments receiving equity credit.
- Existing Hybrids = 3,393 million EUR (at end of 2022) or 3,767 million EUR (at beginning of 2022). 
Taking the average or the year-end balance, the existing hybrids are significantly below the 15% cap (roughly constituting only 4-5% of TAC). This leaves a substantial amount of headroom (around 8,500 million EUR) before hitting the 15% limit.

4. **Market Conditions and Utility Profile:**
ENGIE is a major European utility with a capital-intensive business model (over 55 billion EUR in Property, Plant, and Equipment). Utilities heavily rely on hybrids to optimize their capital structure, bolster equity credit, and maintain solid investment-grade metrics without diluting shareholders. 
Looking at the 2022 market environment, the ECB had begun its rate hiking cycle, moving swap curves significantly into positive territory (5Y swap at 1.726%, 7Y at 1.806%). While rates were rising, credit spreads for European non-financial investment-grade names remained contained (sub-SEN delta for iBoxx EUR Non-Financial IG at 2.295% average). Hybrids remain an attractive and standard tool for utility capital structures, and ENGIE has ample capacity under the S&P cap. 

Because ENGIE's existing hybrid usage is well below the 15% threshold and represents a core component of capital management for European utilities, the company should aggressively utilize the available room under the cap to optimize its weighted average cost of capital and secure equity credit. Therefore, they should utilize the cap to its fullest extent.

<answer>100%</answer>