Over the next 40 years, buildings, which use three-quarters of the electricity, can triple or quadruple their energy productivity, saving 1.4 trillion dollars, net present value, with a 33 percent internal rate of return or in English, the savings are worth four times what they cost.
四十年后 消耗四分之三总电能的建筑物 会将能源生产力提高三到四倍 省下1.4万亿美元的净现值 还有33%的内部收益率 换句话说 省下来的部分相当于成本的四倍