It's not as simple as that... electric propulsion *can* be taken advantage of to lower noise, but that isn't necessarily the aim, nor is such a powertrain inevitably quieter. Take the Royal Navy for example, in the Type 23 ASW frigate and its replacement, the Type 26, electric propulsion (though not in the form of IFEP) is a key component in silencing. OTOH, the Type 45 AAW destroyer with IFEP is notoriously noisy, to the point that it affects its own sonar performance. This isn't a big deal for a what is essentially a single role ship (it was never intended to be especially quiet or have more than a self-defence ASW capability) but it shows that the benefit isn't automatic. Even an electric propulsion system still needs to be purpose-built for low noise, it isn't inherently quiet just by being electric.
That said, given the general purpose role of the Type 054B (with a large part of the PLAN blue-water ASW role resting on its shoulders) we can assume attention will be paid to silencing. If not to go beyond the level achievable with a conventional powertrain (which, after all, can be made very quiet indeed with the right configuration), then at least to attain the required level at lower cost than otherwise possible.
