As you are in the Netherlands and mentioned the three-phase sketch, I assumed you needed it! If you have only a single phase, then the 3-phase sketch isn’t for you (though you can use it if you wish, but you must set the second c.t. to be on phase 1). If you particularly want the energy use accumulated in the Arduino, then I would recommend the new single-phase sketch for the emonTx Shield.
As you are not using the radio to reach your emonPi, the latest version for the emonTx Shield is actually the one here:
EmonTxShieldCM_rfm69n.zip (69.0 KB)
All you need to do is set the radio off (in EEPROM) and it should work for you. You can revert to 115200 baud in the ESP8266 if you wish (otherwise, change the sketch to 9600).
(Note: If you later want to use this sending the data by ISM band radio to the emonPi, it won’t work. This sketch uses the “native RFM69” radio protocol, not the “classic” protocol that the emonPi and the standard sketches still use. Wi-Fi is fine. See The emonPiCM for a full explanation.)