Do I need my own distillation unit for lemongrass oil or can I use a shared one?

You do not necessarily need your own distillation unit. Lemongrass oil is extracted by steam or water-and-steam distillation: the fresh grass is loaded into a still, steam passes through, the oil-laden vapour is condensed, and the oil separates from the water. A still is a real capital cost, so your options are: own unit (only worth it at large scale because the grass must be distilled fresh and close to the field), custom hire or paying a nearby distillation unit per batch, or joining a cooperative or farmer group that shares one still. For small and medium growers, sharing or custom hire is usually far smarter than buying your own. Key practical points: grass must be distilled soon after cutting because it wilts and loses oil, so the still has to be near the field, which is why a shared local unit works well for a cluster of growers. Before investing in any unit, confirm your oil buyer and price, your expected grass tonnage and recovery, and the running cost (fuel, water, labour) in writing or with clear numbers. Many farmers lose money by buying a still before securing an oil buyer. Sort the buyer first, then decide on distillation.