* Reports combined energy segment results

* Flagship EPH earnings down after bumper 2022

* EPH looks at option for Enel stake in Slovak utility

* Sees large investment in renewables, hydrogen-ready facilities

(Adds Kretinsky comment, Slovenske Elektrarne option, coal phase-out, investments, details in paragraphs 3, 6-8, 10-13)

PRAGUE, April 25 (Reuters) - Energy companies controlled by Czech billionaire Daniel Kretinsky's EP Corporate Group on Thursday posted core profit (EBITDA) of 7.3 billion euros ($7.8 billion) for 2023.

Kretinsky, with a net worth of $9.2 billion according to Forbes, built his wealth in the energy sector and has been expanding into other investments across Europe in recent years, including holdings in Britain's Royal Mail, French retailer Casino and German wholesaler Metro.

Energy has remained a key business as the group seeks to transition to lower-emission generation sources after previously growing by buying up unwanted coal-fired plants around Europe.

The group reported the energy business results in the current structure for the first time.

Its flagship energy holding EPH reported a 17% year-on-year fall in earnings before interest, tax, depreciation and amortisation (EBITDA) to 3.6 billion euros in 2023, following a record 2022.

Kretinsky is the 89.3% owner of EP Corporate Group, which in turn holds 56% of EPH.

Investors related to Czech-Slovak financial group J&T, including long-time investment partner Patrik Tkac, hold the rest of EPH, which comprises power generation, heating, gas storage and transmission, and distribution.

EPH said on Thursday it was evaluating the possibility of exercising an option to take over Italian group Enel's stake in main Slovak electricity producer Slovenske Elektrarne, in which they effectively hold 33% each.

Kretinsky's energy assets span the Czech Republic, Slovakia Britain, the Netherlands, Germany, Italy and elsewhere. They have installed capacity of 22 gigawatts (GW) and produced 72.5 terawatt hours (TWh) of power in 2023, placing the group among the biggest producers in Europe.

EPH aims to phase-out coal by the end of the decade. It shut operations of five coal power plants in Germany, Northern Ireland and Slovakia.

EP Corporate Group said it was ramping up spending on renewable projects and hydrogen-ready power facilities, with investments expected to surpass 10 billion euros.

"I believe that hydrogen, together with energy storage solutions, will be pivotal in shaping Europe's energy landscape in the near future," Kretinsky said in a statement.

Kretinsky's bid for the owner of Royal Mail was rebuffed earlier this month, although a source told Reuters an improved offer was being prepared.

($1 = 0.9322 euros) (Reporting by Jan Lopatka and Jason Hovet; Editing by Jan Harvey and Mark Potter )