Page - 95 - in Short-Term Load Forecasting by Artificial Intelligent Technologies

Energies2019,12, 57 costby$35.90,$82.60,and$50.40 for thehousehold, laboratory,andoffice, respectively, if theNaBH4 price is 10NT$/kg. Therefore, the secondoption (using extraNaBH4)will be the better choice if thecostofNaBH4 is less than7.19,10.38,and9.62NT$/kgfor thehousehold, laboratory,andoffice, respectively.Note that theseanalysesarebasedontheworst-caseconditions,where thebatterySOC isat the lowestwhentheextremeweatherhappens.Hence, ingeneral, thecost shouldbe lowerand morebenefitsarepossiblebystoringextraNaBH4with theautobatchsystem[36]. 4.ResultsandConclusions Thispaperhasdemonstratedtheoptimizationofagreenbuildingthatwasautonomousanddid notconnecttothemaingrid. Thebuildingcanbeappliedtoremotestationsandsmall islands,whereno gridpowerisavailable.Wediscussedtheimpactsof threetypical loadsontheoptimizationofahybrid power system. First,webuilt ageneralhybridpowermodelbasedonagreenbuilding inTaiwan. ThemodelconsistedofPV,WT,batteries,PEMFC,electrolyzer,andchemicalhydrogenproduction modules. Second, we evaluated the systemperformance by applying the household, laboratory, andoffice loadprofiles to themodel. Theresults indicatedthat thecombinationofPV,battery,PEMFC, andchemicalhydrogenproductioncanguaranteesystemreliability.Whencomparedwith theoriginal settings, the total system costwas greatly reduced by 38.9%, 40%, and 28.6% for the household, laboratory, andoffice loads, respectively,while the systemreliabilitywas significantly reducedby 4.89%,24.42%,and5.08%,respectively. Third, thecostdistributionshowedsimilar results for the three loads: thebattery, PV, andPEMFCsystemsaccounted for about 25%, 40%, and20%of the system costs forall threecases.Note that thecurrentusageof lead-acidbattery isacompromisebetweencost andefficiency. Forexample, applying thehybridsystemwithLiFebattery [33], theoptimal system costsbecame2.237, 1.846, and1.853perkWhfor thehousehold, lab, andoffice loads, respectively. That ismuch higher than the current optimal costs by the lead-acid battery. Fourth, the energy distributions indicatedthat thePVprovidednearly99%of therequiredenergy,becauseof thecurrent highpriceofhydrogen.Asshownin[33],hydrogenenergywillbecompatiblewhenthehydrogen pricedrops toaboutonethirdof thecurrentprice. Finally,weevaluatedthesafetyof thesesystems underextremeweatherconditionsandproposedtwomethods forextendingsystemsustainability: usingasub-optimaldesignorusingmoreNaBH4. The lattermethodtendedtobemoreflexibleand wasmore able to copewithuncertainties. For example, adding 20kgofNaBH4 will increase the systemsafetyby3.33,2.10,and2.90days for thehousehold, laboratory,andoffice loads, respectively. Thesefindingscanbeconsideredwhendevelopingcustomizedhybridpowersystems in the future. Author Contributions: Conceptualization, F.-C.W.; Methodology, F.-C.W. and K.-M.L.; Software, K.-M.L.; Validation, F.-C.W., andK.-M.L.; Formal Analysis, F.-C.W. andK.-M.L.; Investigation, F.-C.W. andK.-M.L.; Resources,F.-C.W.andK.-M.L.;DataCuration,F.-C.W.andK.-M.L.;Writing—OriginalDraftPreparation,F.-C.W. andK.-M.L.;Writing—ReviewandEditing, F.-C.W.;Visualization, F.-C.W. andK.-M.L.; Supervision, F.-C.W.; ProjectAdministration,F.-C.W.;FundingAcquisition,F.-C.W. Funding: This research was funded by theMinistry of Science and Technology, R.O.C., in Taiwan under GrandsMOST105-2622-E-002-029 -CC3,MOST106-2622-E-002-028 -CC3,MOST106-2221-E-002-165-,MOST 107-2221-E-002-174-, andMOST107-2221-E-002-174-. This researchwasalsofinanciallysupported inpartbythe MinistryofScienceandTechnologyofTaiwan(MOST107-2634-F-002-018),NationalTaiwanUniversity,Center forArtificial IntelligenceandAdvancedRobotics. Theauthorswould like to thankYe-CheYangandI-MingFu forhelpingthesimulation. Thecollaborationandtechnical supportofM-FieldTMaremuchappreciated. Conflictsof Interest:Theauthorsdeclarenoconflictof interest. References 1. Ceraolo,M.;Miulli,C.;Pozio,A.Modellingstaticanddynamicbehaviourofprotonexchangemembrane fuelcellsonthebasisofelectro-chemicaldescription. J.PowerSources2003,113, 131–144. [CrossRef] 2. Gorgun,H.Dynamicmodellingofaprotonexchangemembrane(PEM)electrolyzer. Int. J.HydrogenEnergy 2006,31, 29–38. [CrossRef] 95