A gas blending system configured for generating a blended biogas stream, characterized by : a biogas feedstock source configured to provide a biogas feedstock stream having a first energy content; a first sample take-off probe configured for extraction of a first sample having a first energy content from said biogas feedstock stream for energy content analysis; an analyzer configured for analyzing said first energy content and generating a data signal representing said first energy content; a control unit configured for receiving said data signal representing said first energy content and transmitting a control signal responsive thereto; a refined gas source in selective fluid communication with said biogas feedstock stream and disposed downstream of said first sample take-off probe , the refined gas source being configured for selectively providing a refined gas having a known energy content exceeding said first energy content; a valve in signal communication with said control unit for responding to the transmitted control signal, said valve being configured for controlling a flow of said refined gas provided from said refined gas source , said valve being actuatable between a first open position and a second closed position, where said valve is configured to selectively introduce when in said first open position said refined gas into the biogas feedstock stream to generate the blended biogas stream upon detection of said first energy content falling below a pre-established minimum; a second sample take-off probe for extraction of a second sample from said blended biogas stream, said second take-off probe being disposed downstream of said refined gas source , for energy content analysis and energy content verification of said blended biogas stream as meeting or exceeding said pre-established minimum; and an output of said blended biogas stream. a biogas feedstock source configured to provide a biogas feedstock stream having a first energy content; a first sample take-off probe configured for extraction of a first sample having a first energy content from said biogas feedstock stream for energy content analysis; an analyzer configured for analyzing said first energy content and generating a data signal representing said first energy content; a control unit configured for receiving said data signal representing said first energy content and transmitting a control signal responsive thereto; a refined gas source in selective fluid communication with said biogas feedstock stream and disposed downstream of said first sample take-off probe , the refined gas source being configured for selectively providing a refined gas having a known energy content exceeding said first energy content; a valve in signal communication with said control unit for responding to the transmitted control signal, said valve being configured for controlling a flow of said refined gas provided from said refined gas source , said valve being actuatable between a first open position and a second closed position, where said valve is configured to selectively introduce when in said first open position said refined gas into the biogas feedstock stream to generate the blended biogas stream upon detection of said first energy content falling below a pre-established minimum; a second sample take-off probe for extraction of a second sample from said blended biogas stream, said second take-off probe being disposed downstream of said refined gas source , for energy content analysis and energy content verification of said blended biogas stream as meeting or exceeding said pre-established minimum; and an output of said blended biogas stream. <EOS>