• octane rating and MTBE compatibility: adding ethanol to increase the octane rating during the introduction phase of essEnce5 is positive. Bioethanol’s compatibility with MTBE (an additive used to increase octane rating) will mean that essEnce5 can be distributed through the same channels as those used for 95-octane petrol, so these factors will not affect the choice of distribution method
• fuel stability: ethanol blended petrol has a great affinity for water. Various measures are planned to overcome this problem (using anhydrous ethanol, avoiding introduction of water by blending with petrol at the last moment i.e. just before distribution, blending as high a proportion of ethanol as possible, etc.)
• contraction effect and metering for tax purposes: whether or not ethanol is taxed, it will be necessary to measure the exact proportion of the petrol-ethanol blend. When ethanol is added to petrol, the resulting blend undergoes contraction and a drop in temperature, which makes it difficult to measure precisely the quantity of each constituent.  In the case of splash blending, two meters measure the quantity of each product just before blending.

E85 is not intended to be used as conventional petrol but as a petrol replacement in flex-fuel (FFV) vehicles. The higher octane content increases engine performance and so partially compensates for the lower calorific value of ethanol compared to petrol.