Bio fuels, bio energy or bio CO2 mitigation if very very difficult due to the extremely low efficiency of plants at converting solar radiation to other forms of energy.
Lets look at your example of an acre of kenaf. Your kenaf converts 10 tons of carbon to carbon compound (so removes the CO2 from the air). That same acre of land covered with present day PV (efficiency of only 15% or less on average) would produce 3000KWH per day of electricity. A typical fossil fuel power plant produces about 2lbs of carbon emissions per KWH of electricity. So an acre of PV panels will effectively eliminate as much carbon emissions in 3 days as an acre of kenaf in a year.
Solar thermal can reach efficiencies of 50-70% (even higher for pool heaters) when producing heat and hot water, so an acre of solar thermal panels can offset as much carbon emissions in one day as an acre of kenaf can in a year.