The load on today's service-oriented systems is strongly varying in time. It is advantageous to conserve energy by adapting the number of replicas according to the recent load. Over-provisioning of service replicas is to be avoided, since it increases the operating costs. Under-provisioning of service replicas leads to serious performance degradation and violates service-level agreements. To reduce energy consumption and maintain appropriate performance, we study two service replication strategies: (1) arrival rate based and (2) response time based policy. By simulation, we show that the average number of service replicas and response time can be reduced especially when combining our proposed replication strategies and load balancing schemes. © 2011 IEEE.