報告書番号

Y12031

タイトル（和文）

メガソーラー発電技術のライフサイクルCO2排出量評価

タイトル（英文）

Evaluation of Life Cycle CO2 Emission of Large-scale Grid-connected Photovoltaic Systems

概要 （図表や脚注は「報告書全文」に掲載しております）

太陽光(PV)発電システムは、運用（発電）段階では二酸化炭素(CO2)を排出しないものの、太陽電池(PV)パネル製造時にCO2を排出するほか、施工時にCO2排出原単位の大きい建材を相当量用いる。発電技術毎の温室効果ガス排出量比較においては、発電技術のサプライチェーンの全てを評価対象範囲（システム境界）とする必要があるが、PVシステムも例外ではない。
2009年に行った評価[1]では、PVシステムについては住宅用のみを対象として検討を行ったが、2012年7月に売電用大規模PVシステムからの買い取り価格が大幅に引き上げられた結果、1MWを超えるPVシステムが複数運開している。
このため、現在商用目的での導入が進んでいる1MW、2MW、、5MWに加え10MWのPVシステムを対象にLC-CO2排出量評価を行った結果、住宅用PVシステムのLC-CO2排出量38 g-CO2/kWhに比べて、メガソーラー発電システムのLC-CO2排出量は、55～56g-CO2/kWhとなり、住宅用PVシステムに比べてメガソーラー発電システムのLC-CO2排出量は45%～48%高くなる。

概要 （英文）

While solar photovoltaic (PV) generation systems emit no carbon dioxide (CO2) during power generation, substantial amount of CO2 is discharged during the PV panel manufacturing. Also, significant amounts of those materials with high CO2 emission factors, such as silicon, glass and aluminum, are used upon the construction. In order to perform environmental impact assessment of power generation technologies, which the PV systems are none of exception, it is essential to evaluate CO2 emissions covering the whole supply chain. In 2009, CRIEPI evaluated the life cycle CO2 (LC-CO2) emissions of major generation technologies including a PV system for households, but large-scale PV systems were excluded due to data constraints at the time. Later in July 2012, the purchase price per kWh generated by the large-scale grid-connected PV systems by utilities were pulled up sharply, which is expected to stimulate their rapid introduction. Under these circumstances, there arises an urgent need to add large-scale PV generation technology to the LC-CO2 comparative assessment.
This report evaluates LC- CO2 emissions of large-scale grid-connected PV model plants at 1MW, 2MW, 5MW and 10MW capacity to be built in Japan with detailed evaluation of material requirements, with supplementary cases of PV module panel imported from different countries.
As the main results, the LC-CO2 emissions of large-scale grid-connected PV plants turned out in the range of 55.3 to 56.3g-CO2/kWh, which are 45-48% higher than those of small scale residential systems at 38g-CO2/kWh. Larger material requirements of the
mounting components for PV modules, as well as more complicated equipment for power conditioning, of large-scale plants compared with household systems drive LC-CO2 emissions of the former to the higher levels.

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