US private equity firm KKR & Co (<a href="https://www.nyse.com/quote/XNYS:KKR" target="_blank">NYSE:KKR</a>) has agreed to pour up to EUR 400 million (USD 429.2m) for the development and construction of primarily green hydrogen and ammonia projects as part of a new Power-to-X (P2X) joint venture with Spanish renewables firm Ignis.