The phrase "a substantial substitute" is correct and usable in written English.
You can use it when discussing an alternative that is significant or considerable in nature, often in contexts like product comparisons or academic discussions.
Example: "The new software serves as a substantial substitute for the outdated system, offering improved functionality and user experience."
Alternatives: "a significant alternative" or "a considerable replacement."
Mushrooms and eggs go together well, combining a meaty and substantial substitute to pork.
The vision was to replace part of the crude oil-derived heating oil and to substitute a substantial part of the oil-derived motor fuels not only for stationary applications, but hopefully also for mobile internal combustion engines in passenger cars, busses, and trucks.
With such a substantial number of skin substitutes available for promoting healing of burns, plastic surgeons should understand the benefits and pitfalls of each, in order to help guide effective treatment.
And given Mr Obama's international popularity, it is quite possible that he might fare better abroad than he could with the Republican minority.This isn't a foolproof plan, and it certainly isn't a substitute for a substantial domestic stimulus, but Mr Obama needs to be exploring all avenues.
These species should be sufficiently close so that the intergenic regions could be unambiguously aligned, yet a substantial fraction of nucleotides had been substituted since the species diverged from their common ancestor.
Current low-carbon technologies cannot substitute for fossil fuels without a substantial economic penalty on carbon emissions.
They almost certainly devoted a substantial share of their earned income to purchasing substitutes for such services, including paid child care and meals away from home.
During continuous RRT, according to conventional acid base thinking, there is a substantial loss of endogenous bicarbonate, which must be substituted by the addition of 'buffer' substances.
In a minority of cases, but a substantial minority, petting leads to orgasm and may be a substitute for coitus.
On the way, he invited me to join a contest he was sponsoring, with a substantial prize for the person who came up with the best substitute for the word "sunset".
