Based on the financial data and the guidelines provided, the assessment for REN (Redes Energéticas Nacionais, SGPS, S.A.) to issue hybrid bonds in the next 18 months points to 0% of total adjusted capital. 

Here is the step-by-step reasoning:

1. **Historical Precedent and Capital Structure**: The strongest indicator is that the company has never issued hybrid bonds in the past ("First year of hybrid bond issuance: never"). As noted in the guidelines, an entity's previous level of hybrid bond issuance is a highly reliable signal. With no current hybrids in the capital structure, there is a clear strategic precedent to avoid this instrument.

2. **Improving Leverage Metrics**: REN exhibits a stable to improving financial risk profile. Moody's adjusted leverage trend for 2022 is explicitly listed as "Improving". The company’s S&P Net Debt to EBITDA sits at 4.37x and its FFO to Net Debt is at 16.86%. For a regulated utility (which typically benefits from strong, predictable cash flows and regulatory advantages under S&P criteria), these metrics point to a solid investment-grade profile that does not require the equity credit relief typically sought through hybrid issuance. 

3. **Cost of Debt**: The macroeconomic data highlights a massive spike in benchmark interest rates in 2022 (e.g., the 5-year swap curve jumped from -0.264% in 2021 to 1.726% in 2022, and the sub-senior delta widened as well). Issuing a hybrid bond in this environment would carry a substantial subordination premium. Because REN's standard cost of debt is already moving higher with the broader market, introducing costly hybrid securities to the capital structure would materially and unnecessarily increase the company's blended cost of capital.

4. **Refinancing Needs**: While REN has €638 million in current borrowings, it generated over €613 million in operating cash flows during the year, alongside significant flexibility with its cash buffers and available liquidity. This limits any immediate necessity for transformational refinancing via complex subordinated instruments. 

Given the absence of hybrid instruments in REN's history, its improving leverage metrics, the higher cost of subordinated debt in the prevailing rate environment, and the lack of outsized M&A/capex pressures requiring capital structure remediation, there is no rationale for the entity to utilize hybrid bonds.

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