The phrase "an effective replacement" is correct and usable in written English.
You can use it when discussing an alternative that successfully serves the same purpose as something else.
Example: "The new software proved to be an effective replacement for the outdated system we were using."
Alternatives: "a suitable alternative" or "a viable substitute."
Brandon Carr may have departed, but Stanford Routt was expected to be an effective replacement.
Mr. Bush kept saying that he wanted to close Guantánamo Bay but could not find an effective replacement for it.
Kenyon Martin has been an effective replacement for Tyson Chandler while Chandler rests with a bulging disk in his neck.
(Mr. Peterson said the U-Sand is an effective replacement for the buffer and is much easier to use).
From its performance, one can conclude that the DCRM method is an effective replacement for the conventional rod worth measurement method.
To be an effective replacement (or surrogate, as it is often called) of clinical outcomes, the measure of disease activity needs to be objective, sensitive, cost effective, accurate, and reproducible.
Without a more effective replacement for foreign security companies, Mr. Karzai's order could make the situation in Afghanistan significantly worse.
Serious money can't buy you love, or even a reliably healthy right-hander (see: Brandon McCarthy), but it appears that relative pocket change can buy you a surprisingly effective replacement.
Electric vehicles (EVs) avoid the use of petroleum, and so are seen as an efficient and effective replacement for traditional internal combustion engine based vehicles (ICEVs).
We have designed an inexpensive and effective replacement for commercial IR sensors that can be attached to enclosures to monitor animal locomotion.
The five-year deal with the Pentagon to produce explosives at a plant in Tennessee includes a further order for IMX-101 munition that is seen as a safe and effective replacement for TNT in artillery rounds.
