At present rates of demand, the world has enough oil in known and economically viable reserves to last for more than 40 years, enough gas for more than 60 years and enough coal for more than 230 years.

【翻译】按目前的需求速度，在已知的、经济上切实可行的储量中，世界上有足够的石油可持续40多年，有充足的天然气可持续60多年，有足够的煤炭可维持230多年。

【结构分析】

At present rates of demand（状语）, the world has enough oil （主、动、宾）in known and economically viable reserves （地点状语） to last for more than 40 years（不定式作定语，修饰oil）, enough gas for more than 60 years （跟oil是并列宾语）and enough coal for more than 230 years. （跟oil是并列宾语）