Most wave energy devices currently under consideration will employ large volumes of concrete in the construction of their main structures. Concrete is made up from three basic constituents; cement; aggregate and water. Of these the major energy input to concrete is embodied in the cement. For a typical strong concrete (Grade 40: 40N/mm2 28 day strength) made at a wave energy device construction site using ordinary portland cement (OPC), from Scottish mix of supply between 83% and 98% of the

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... gy input is embodied in the cement. The precise energy requirement of concrete is highly site specific. The type of aggregate, its availability and proximity to the wave energy device construction site (WEDCS) all affect the energy requirement of the aggregates and therefore of the concrete. Thus, to study ways of reducing the energy requirement of concrete, it is appropriate to investigate what energy savings are possible in the production of cement for the construction of wave energy devices. This report concentrates on the current practice in the U.K. cement industry and then outlines how the energy saving options described in Energy Audit 11 'The Cement Industry' (1) can be applied to the production of cement which will then be supplied, to wave energy device construction sites in Scotland. The contribution that the device structures make to the energy input to the whole wave energy system varies with the system studied. Thus the proportion of the total system energy input which is embodied in the cement used to construct the devices varies widely between wave energy systems. For example, for the NEL Oscillating Water Column Breakwater device, the cement I makes up 18% of the total energy input to the system,which makes it one of the largest single energy inputs. For this device then, any reduction made in the energy requirement will have an important bearing on its viability in energy terms. In other wave energy devices cement plays a less important role. The Lancaster Flexible Bag system has about 9% of its energy in [...]