See the light when milking
They have found that moving from double T8 fittings to half the number of T5 fittings would reduce power consumption on lighting by 40%, while still providing the recommended 500 lux of brightness.
Work at Moorepark showed that lighting accounts for 7% of total electrical energy used on Irish dairy farms. Moisture-resistant double fluorescents and high-bay metal halide lamps are the two most common types of lighting used on Irish dairy farms.