Low-carbon energy transitions aim to stay within a carbon budget that limits potential climate change to 2 °C—or well below—through a substantial growth in renewable energy sources alongside improved energy efficiency and carbon capture and storage. Current scenarios tend to overlook their low net energy returns compared to the existing fossil fuel infrastructure. Correcting from gross to net energy, we show that a low-carbon transition would probably lead to a 24–31% decline in net energy per capita by 2050, which implies a strong reversal of the recent rising trends of 0.5% per annum. Unless vast end-use efficiency savings can be achieved in the coming decades, current lifestyles might be impaired. To maintain the present net energy returns, solar and wind renewable power sources should grow two to three times faster than in other proposals. We suggest a new indicator, ‘energy return on carbon’, to assist in maximizing the net energy from the remaining carbon budget.

低碳能源转型的目标是通过可再生能源的大幅增长，同时提高能源效率以及碳捕获和存储，将碳潜在预算限制在2摄氏度（甚至更低）之内，以将其控制在碳预算范围内。与现有的化石燃料基础设施相比，当前的情景往往忽略了其较低的净能源收益。从总能源到净能源的校正，我们表明，低碳转型可能会导致到2050年人均净能源下降24-31％，这意味着最近的年均0.5％的上升趋势得到了强有力的逆转。除非在未来几十年中实现大量的最终使用效率节省，否则当前的生活方式可能会受到影响。为了维持目前的净能源收益，太阳能和风能可再生能源的增长速度应比其他提议快两到三倍。