The phrase "already existing plants" is correct and usable in written English.
It can be used when referring to plants that are currently in place or have been established prior to a certain point in time.
Example: "The project will focus on enhancing the efficiency of already existing plants to reduce overall energy consumption."
Alternatives: "currently established plants" or "pre-existing plants".
The study dealt exclusively with the licensing of future plants, but did not deal with the problems posed by the continued operation of the 72 already existing plants.
This optimal operation strategy can be conveniently applied both to already existing plants and to the choice of new design plant configurations.
The new Youth Front and other crusaders for a bolter environment demand that, to begin with, new industries be barred from the Venice area and already existing plants chip in for the construction of an aqueduct to supply them with water from a safe distance in land.
Careful selection of tree species, control of already existing plant and microbial flora, analyzes of soil properties, nutrients, prediction of further development of herbaceous, and microbial communities, along with possibility of amendment and herbicide applications is essential for successful mine site restoration using trees.
Even though health risk methods are already established, majority are for existing plants assessment.
Hereby, we focused on already available technologies for retrofitting existing plants, as the level of the current incentives of the feed-in tariff system is expected to result in a rather small increase in the total installed capacities in the years to come [23, 25].
SES has already spent $140 million to develop existing plants worth nearly $1 billion.
Proponents of nuclear power, recognizing these dangers, propose new "safe" future generation technology (which does not now exist), assembly line production of standard designs, and continued operation of existing plants that are already beyond their 40-year design lifetime in the United States.
Many new plants are planned next to existing plants, where nuclear and electricity infrastructure already exists.
There may be a case for extending the licenses of existing plants, as has already happened in several cases, or for building new plants on existing nuclear sites where the risks are already understood.
But it would not apply to existing plants or those already under construction.
