At euro15 ($22) a tonne the price is high enough to induce power companies to switch some generation from coal to gas at the margin, but not high enough to encourage much innovation.

• 每吨15欧元（22美元）的碳税，足够让电力公司从煤发电转向用气发电，但是这样的碳价对于电力行业的改革创新没有起到多大推动作用。