Harvesting elevation potential from mountain forests

Abstract

ABSTRACTFor a limited set of conditions we have shown that recovering braking energy from log trucks descending from high elevation stands to lower elevation manufacturing facilities can reduce the size of the battery required to run a log truck. Adding level highway hauls after descending from the higher elevation stands quickly increases the required battery capacity. The effect of conversion efficiency on the required battery capacity is correlated with the change in elevation along the haul route. At a conversion efficiency of 100% (battery-to-wheels and wheels-to-battery), the cumulative battery usage on the base profile (elevation factor = 1.0) is only one-half of what it would have been compared to a level road of the same horizontal length (elevation factor = 0.0). When the conversion efficiency is set to 60%, the cumulative battery usage for the base profile would be the same as if the truck had been on a level road of the same horizontal distance. For the actual haul route considered in this paper the minimum battery mass required for a single round trip is limited by peak power requirements; however, energy storage becomes limiting as longer level highway haul sections are added.