3.1.1. LCC for TEPs

The LCC is, in essence, an accounting structure containing the mathematical formulations that can be used to estimate the associated costs of the projects during their lifespan [48]. The benefits obtained as a result of determining the LCC of these sorts of projects are summarized as follows [49,50]: (i) the life cycle concept results in earlier actions by which to generate revenue or in lower costs than might otherwise be considered; (ii) better decisions can be made as the result of a more accurate and realistic assessment of revenues and costs, at least within a particular life-cycle stage; (iii) it can promote long-term rewarding in contrast to short-term profitability rewarding; (iv) it provides a better understanding as regards the difference between the acquisition costs and the operating and support costs, and (v) it encourages businesses to find a correct balance between investment costs and operating expenses. In the particular case of TEPs composed of first generation TECs, the stages of which the LCC of the proposed methodology is composed are the following (see also Figure 12). A detailed description of all the structures of the subcosts and the subsequent procedure employed to compute them can be found in [19,46]:

**Figure 12.** Life cycle costs for tidal energy projects composed of gravity-based first generation TECs.


Once these costs have been computed, the total LCC of a TEP yields the following result:

$$LCC\_{TP} = C\_1 + C\_2 + C\_3 + C\_4 + C\_5 + C\_6.\tag{1}$$
