Reduction of Energy Consumption through the Application of Energy Management Tools

MWH have undertaken energy management studies for a number of water companies in the UK, utilising the state of the art modelling and optimisation tools provided by the H2ONET suite of software. The principal aim of these studies has been to identify the scope for reductions in both energy cost and energy consumption, through more optimal operation of the network assets. The potential savings associated with water network operation can be realised in three key ways: 1) More optimal use of lower cost water source works, 2) Savings realised though a reduction in the overall level of energy consumed in the operation of the pumping assets, and 3) Savings associated with the exploitation of lower cost electricity. The H2ONET hydraulic modelling package has an Energy Management module that allows the accurate cost of network operation and the power consumed in that operation to be calculated. The software also has a powerful genetic algorithm based optimisation module (Scheduler) that can identify a least cost pump operating strategy that takes into account the following factors:- 1) The cost per Ml of water produced at each source works — this allows preferential selection of the sources with the lowest energy consumption, 2) Delivery of water to its destination by the most efficient means — if multiple potential routes/means of delivering water to specific locations exist, H2ONET can evaluate and select the least cost method of achieving this, 3) The optimal pump configuration to achieve a user defined hydraulic end status for the network, and 4) Calculation of the operating efficiency of each pump unit (based upon pump efficiency curves) and selection of the most efficient pump units. The results of the studies carried out to date, based on real networks and using real data, have demonstrated that savings of the order of 5% to 12% can be realised by the application of the energy management tools and implementing the recommended system changes.