NOVELTY - Apparatus (10) for cleaning the gas produced by a gasifier (12), comprises: an input line (16) suitable for conveying the flow of gas (G) to be cleaned; a first scrubber (20) suitable for treating the flow of gas (G) entering from the line (16); a duct (27) for introducing additives into the basin (22); a wet electrostatic precipitator (40) suitable for treating the flow of gas (G) already treated by the first scrubber (20); and an output line (18) suitable for conveying the flow of clean gas (G) to an external user unit.    USE - The apparatus is useful for cleaning the gas produced by a gasifier (claimed).    ADVANTAGE - The apparatus efficiently and effectively purifies the fuel gas produced by the gasifier.    DETAILED DESCRIPTION - Apparatus (10) for cleaning the gas produced by a gasifier (12), comprises: an input line (16) suitable for conveying the flow of gas (G) to be cleaned, output by the gasifier (12); a first scrubber (20) suitable for treating the flow of gas (G) entering from the line (16), the scrubber (20) comprising: means (21) for spraying a mixture TAR, based on Lars without the presence of water, into the flow of gas (G), a basin (22) suitable for storing in the first scrubber (20) a quantity of mixture TAR in the condensed state, a recirculation circuit (23) suitable for removing the mixture TAR from the basin (22) and supplying it to the spraying means (21), a bleeder pipe (24) suitable for removing the condensed pollutants from the bottom of the basin (22) and conveying them to the gasifier (12), and a high-temperature heat exchanger (25) suitable for exchanging heal, between the mixture TAR in the recirculation circuit (23) and a service fluid in an auxiliary circuit (26); a duct (27) for introducing additives into the basin (22); a wet electrostatic precipitator (40) suitable for treating the flow of gas (G) already treated by the first scrubber (20), the precipitator (40) comprising: a tank (42) suitable for collecting the tars and the water condensed during cooling of the gas (G), a third bleeder pipe (44) suitable for removing the condensed tars from the bottom of the tank (42) and conveying them to the gasifier (12), and a discharge pipe (46) suitable for removing the excess aqueous mixture from the lank (42) and conveying it externally; and an output line (18) suitable for conveying the flow of clean gas (G) to an external user unit; and where the apparatus (10) also comprises cooling means (50) suitable to remove a further quantity of heat from the gas (G) before the gas (G) is conveyed from the output line (18) to an external user unit, the cooling means (50) being positioned between the first scrubber (20) and the wet electrostatic precipitator (40). INDEPENDENT CLAIMS are:    (1) plant (100) for the production of energy from biomass, comprising a gasifier (12), an apparatus (10) according to any one of the preceding claims for cleaning the gas (G) produced by the gasifier (12), and a unit for using the gas (G); and    (2) a method for cleaning the gas (G) produced by a gasifier (12), comprising: conveying the flow of gas (G) to be cleaned from the gasifier (12) to the apparatus (10); conveying the flow of gas (G) via the input line (16) to the first scrubber (20); spraying a mixture TAR based on tars without the presence of water, into the flow of gas (G); storing a quantity of mixture TAR in the condensed state inside a basin (22) of the first scrubber (20); recirculating the mixture TAR by removing it from the basin (22) and supplying it to the spraying means (21); removing the condensed pollutants from the bottom of the basin (22) and conveying them to the gasifier (12); exchanging high-temperature heat between the mixture TAR and a service fluid in an auxiliary circuit (26); conveying the flow of gas (G) from the first scrubber (20) to the cooling means (50); removing a further quantity of heat from the gas (G); conveying the flow of gas (G) from the cooling means (50) to the wet electrostatic precipitator (40); treating the flow of gas (G) in the precipitator (40); collecting inside a lank (42) the tars and the water condensed during cooling of the gas (G); removing the condensed tars from the bottom of the tank (42) and conveying them to the gasifier (12); removing the excess aqueous mixture from the tank (42) and conveying it externally; and conveying the flow of clean gas (G) from the precipitator (40) via the output line (18) to an external user unit.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a plant for the production of energy from biomass, comprising the gas cleaning apparatus.    Apparatus (10)    Gasifier (12)    Input line (16)    Output line (18)    Scrubber (20)    Means for spraying a mixture TAR (21)    Basin (22, 32)    Recirculation circuit (23, 33)    Bleeder pipe (24, 34, 44)    Heat exchanger (25)    Auxiliary circuit (26)    Duct (27)    Second scrubber (30)    Means for spraying a liquid into the flow of gas (31)    Wet electrostatic precipitator (40)    Tank (42)    Discharge pipe (46)    Cooling means (50)    Plant (100)