講演情報
[P003A [発表前半]]日本における環境価値取引へのブロックチェーン活用に関する経済的・時間的合理性の検証
○竹岡 篤志1[修士課程]、エラクネス ヨガラジャ2 (1. 北海道大学大学院工学院、2. 北海道大学大学院工学研究院)
キーワード：
ブロックチェーン、環境価値取引、スマートコントラクト、GX排出量取引制度、レイヤー2
Japan's Green Transformation Emissions Trading System (GX-ETS) entered its mandatory participation phase in FY2026, requiring industrial emitters exceeding 100,000 tCO₂/year to hold and surrender emission allowances. Existing environmental value trading mechanisms—over-the-counter (OTC) brokerage, the Japan Exchange Group (JPX) carbon market, and the Japan Electric Power Exchange (JEPX), which charges JPY 0.001/kWh plus an annual membership fee of JPY 600,000—suffer from price opacity, restricted institutional access, and slow settlement cycles. Blockchain-based smart contracts have been proposed as a remedy, and a prior empirical study (Al Sadawi and Ndiaye, 2021) reported a total transaction cost of USD 147.21 per trading cycle on the Ethereum virtual machine.
This study empirically evaluates whether blockchain-based environmental value trading has become economically and temporally rational under 2025–2026 conditions. Two research questions are addressed: RQ1 (is transaction-execution cost competitive with traditional trading methods?) and RQ2 (are confirmation times sufficiently short for practical operations?).
A three-stage experimental design was employed, using the same four smart contract operations as the prior study (Deploy, Register, BuyEmission, BuyOffset). Stage 1 reproduced the 2021 experiment using Remix IDE under 2026 gas-price conditions. Stage 2 established a zero-latency computational baseline using Hardhat local simulation. Stage 3 conducted 30 independent trials on Arbitrum Sepolia (Ethereum Layer 2, Optimistic Rollup) testnet.
Transaction costs per full trading cycle on Arbitrum Sepolia decreased by more than 90% relative to the 2021 baseline of USD 147.21. Similarly, the mean confirmation time was reduced by approximately 90% compared to 2021.
These results demonstrate that blockchain-based environmental value trading on Ethereum Layer 2 is now economically rational and operationally viable, meeting the cost and speed requirements of Japan's GX-ETS as it enters its mandatory phase.
This study empirically evaluates whether blockchain-based environmental value trading has become economically and temporally rational under 2025–2026 conditions. Two research questions are addressed: RQ1 (is transaction-execution cost competitive with traditional trading methods?) and RQ2 (are confirmation times sufficiently short for practical operations?).
A three-stage experimental design was employed, using the same four smart contract operations as the prior study (Deploy, Register, BuyEmission, BuyOffset). Stage 1 reproduced the 2021 experiment using Remix IDE under 2026 gas-price conditions. Stage 2 established a zero-latency computational baseline using Hardhat local simulation. Stage 3 conducted 30 independent trials on Arbitrum Sepolia (Ethereum Layer 2, Optimistic Rollup) testnet.
Transaction costs per full trading cycle on Arbitrum Sepolia decreased by more than 90% relative to the 2021 baseline of USD 147.21. Similarly, the mean confirmation time was reduced by approximately 90% compared to 2021.
These results demonstrate that blockchain-based environmental value trading on Ethereum Layer 2 is now economically rational and operationally viable, meeting the cost and speed requirements of Japan's GX-ETS as it enters its mandatory phase.