The environmental approval for Aemetis' pipeline extension is a positive development for the company, likely to improve its operational efficiency and capacity for RNG production. This could lead to increased revenues and profitability in the short term, as the company can potentially transport more biogas and produce more RNG, which is in high demand due to its clean energy profile. Investors may view this news as a sign of progress in Aemetis' growth strategy and commitment to sustainability, which could positively influence the stock price.