Brownfield- The projects team uses this methodology to refer to execution of a project - where some facilities are available at the execution worksite. Normally - when there is an expansion of an existing plant - some inputs required by the new plant - particularly in terms of utilities and raw material have been taken care during the design of the previous plant. Such project - where there is an expansion of the existing facility - are referred to as Brownfield Projects. 

Example - we are executing the an expansion of a new power plant, where we intend to add one more unit of say 660MW, then there will be several systems as Demineralized water, raw water etc - which can cater to the requirements of the new plant without needing any additional effort as during the execution of the previous phase, the capacity of the new unit was taken into the account. Further - other additional infrastructure requirements - say roads, railway siding etc - will also be available making the execution of a brownfield project much simpler.

The term is used in conjunction with Greenfield Project - which by default means that you are clearing the Greencover (removing forest) to set up a plan. Essentially greenfield means that there is nothing available at the location where the project needs to be executed and we have to start from scratch.  

tBits caters to both the Greenfield and Brownfield Projects in  Process, Minerals, Mining, Power Generation & Oil & Gas Segments.