夏季缺電之最適限電策略︰農業─食品生產鏈亦須共體時艱？

Optimal Electricity Rationing Strategy during Summer Season: Shall Agri-Food Supply Chain Sectors Ally to Tough It Out?

台灣夏季高溫酷熱使得各產業夏月用電量較全年月平均高出5%~24%。台電公司發電機組的備轉容量率在過去幾年的夏季也多次逼近限電警戒值（6%）。在未來氣候變遷趨勢下，夏季極端高溫發生機率提高，發電容量因受環保及社會因素影響難以同步擴充，限電極可能成為台灣在夏季必須面對的挑戰。本文旨在建構一描繪台灣經濟體內所有生產及消費部門相互依賴連結的線性規劃產業關聯分析（linear programming input-output analysis，以下簡稱LPIO）模型，用以求解經濟成長過程中若遇夏季供電瓶頸時之可行產業最適用電配置（限電）策略─限制用電之產業組合及配比。本研究首創以夏季產業關聯表（Input-Output Table，以下簡稱IOT）來校準LPIO 模型，切合實際地反映產業的季節性投入需求，以提升總體多部門模型之應用分析在政策制定參考上的實用性。以夏季IOT 資料校準LPIO 模型所求算出的產業最適限電策略需要相對較多產業加強配合節電。農業──食品生產鏈上各產業的用電密集度雖較第二及第三級產業為低，然而，因其產品之單位內含用電量所能創造的總體附加價值較低，以故，當供電不及經濟成長之需求而須進行限電最適配置時，漁產、畜產、加工食品、飲料、住宿及餐飲等產品之最終消費亦須共體時艱，配合最適限電配置原則而犧牲成長，進而帶動其相關上下游產業減產以減少用電。農產部門亦會受到產業間相互的投入產出關聯影響而減產。農業──食品生產鏈之上下游產業若能進一步提升用電效率，降低其產品內含電力使用量，限電優先順位可望後移，在缺電瓶頸時期得以倖免於限電危機。

In Taiwan, industrial electricity consumption in summer time outweighsthe seasonal average by around 5%~24%. Over the past few years,percent operating reserve in hot summer days several times approached thecritical threshold of 6% for power rationing. Owing to climate change,extreme high temperatures are projected very likely to occur frequentlyduring summer time in Taiwan. Yet, expansion in the installed capacity ofpower generation is fiercely stalled domestically due to environmental andpolitical concerns. It is foreseeable that rationing will be necessary in orderto tackle the problem of excess demand for electricity in the summer time.We built a linear programming input-output analysis (LPIO) model toinvestigate the optimal strategy for electricity rationing across sectors underthe circumstances of excess demand for electricity in the summer time dueto high temperatures. Our LPIO model finds the optimal sectoral allocationof the scant electricity supply according to the value-added per unit of powerembodied in the commodity consumption (VAEE). The novelty of thisresearch is that our LPIO model is calibrated to a summer-based inputoutputtable (IOT) of Taiwan, so as to reflect the seasonal heterogeneity insectoral power requirement. As compared with a conventionally annual-IOT calibrated LPIO, the results from our summer-LPIO model indicate that itwould require more sectors (both producing and consuming sectors) to cut their power demand so as to protect the power system from outage whilesecuring economic growth. Given the current attainable VAEE, sectors ofthe agri-food supply chain (AFSC), which tend to consume less electricityper unit of output as compared with industrial and services sectors, will alsoneed to cut production so as to make way for the economy to attain as highas possible GDP growth in the hard times of electricity insufficiency.Improvement in the efficiency of electricity use will be helpful for the AFSCsectors to be secured against electricity rationing.