The invention is a combination accumulator and reservoir which stores energy when the accumulator deforms from its original shape in response to the flow of a pressurized fluid from the reservoir. The stored energy is returned when the fluid flow is reversed and the accumulator discharges the fluid and returns to its original shape. At least one part of the novelty of the invention is that the accumulator and the fluid reservoir reside in the same housing such that the volume of each varies inversely. Accordingly, the invention is more compact and weighs less than conventional accumulators. Another feature of the invention is that fluid is located around the bladder accumulator to lubricate contact between the bladder and sides of the reservoir.