Given this Y27632 performance, a goal was fixed in this work to evaluate the economical performance of the storage device and its contribution to operational profit for each service.
As the considered services are single cases or combinations of all-day services S1 and/or S2a2 and peak hour service S2d, the revenues from injected power to the grid will be given by:equation(32)RevenuesPelamis+Storage=EinjNPH×c1+EinjPH×c2RevenuesPelamis+Storage=EinjNPH×c1+EinjPH×c2where c1 and c2 are the FIT for non peak hour (NPH) and peak hour (PH) services, with a price condition holding as c1 < c2.
The contribution of the storage device to operational profit will be computed by the difference:equation(33)ProfitStorage=NPVPelamis+Storage−NPVPelamisProfitStorage=NPVPelamis+Storage−NPVPelamis
From the results obtained in the previous sections, services S1, S2a2, S4a-b and S5a-b are retained for the economical analysis. For services S1 and S2a2 second options strategies are considered. For S1, as a complement to the maximum-charge/minimum-discharge strategy (S1 +/−), a second exact-charge/minimum-discharge strategy (S1 0/−) is also studied. The exact-charge means that the charge zone is limited to Pout > Pbid. A Higher storage size is obtained with strategy 0/−, at the benefit of higher injected energy (see Table 5). For S2a2, the results obtained with tol = 15 and tol = 20 kW are compared. The technical analysis results, including the optimal storage size and injected energies, for each of these services are resumed in Table 3. It is assumed that the FIT for output energy injected during a DTR condition is half the value during normal power injection.