 If the fossil energy spent on the operation is high compared to the amount of produced energy, the total CO2 footprint (CO2 emissions from operation plus plant burning, minus carbon sequestration) can approach, match or even exceed the CO2 footprint originating from burning fossil fuels exclusively, as has been shown to be the case for several first-generation biofuel projects.Transport fuels might be worse than solid fuels in this regard.The problem can be dealt with both from the perspective of increasing the amount of carbon that is moved below ground (see Carbon sequestration, above), and from the perspective of decreasing fossil fuel input to the above-ground operation.