The Palatana Power Plant in Tripura is a

Power plants are classified by the primary energy source they convert into electricity: controlled nuclear fission, combustion of a fossil fuel such as natural gas, combustion of organic biomass, or the Earth's internal (geothermal) heat. Identifying a plant's type means identifying which of these energy inputs it actually uses.

The Palatana Power Plant in Tripura is operated by OTPC (ONGC Tripura Power Company) as a natural-gas-fuelled combined-cycle power plant. It runs on natural gas supplied by ONGC's gas fields in Tripura: the gas is burned in gas turbines, and the hot turbine exhaust is then used to raise steam for a second, steam-turbine stage — the standard combined-cycle design used to raise overall efficiency.

Contrasting with the other classifications offered:

• Nuclear power plants run on controlled fission of a radioactive fuel such as enriched uranium; the Palatana plant has no reactor core or fissile-fuel supply.

• Biomass power plants burn organic matter such as crop residue or wood waste; the Palatana plant's fuel is piped natural gas, not solid biomass.

• Geothermal power plants draw on underground heat or steam reservoirs; the Palatana plant's energy input is gas combustion, not geothermal heat.

Independent confirmation: OTPC's own plant-details page and a Government of India Press Information Bureau release both describe Palatana as a natural-gas-fuelled plant, corroborating the classification from two independent authoritative sources.

Therefore, the Palatana Power Plant is a Gas-based Power plant.