思路解析：
1. 分段原则为：相同趋势的分在同一段落，具体为：最主要的能源一段，次重要的能源一段，最不重要的能源一段。
2. 由于线段过多，所以线段的描述尽量简洁，只描述最重要的特征(Max,Min,上升，下降，波动，交点)，其他数据一律不写。
3. 不用每条线都描述，只重点描述几条线的共性。
4. 注意句式的多样性，即动词表达和名词表达的交替使用。
参考范文：
The graph shows consumption of energy in the U.S. since 1980 with projections through 2030.
The historical trends show Petrol and Oil as the major sources of fuel, rising from 35 quadrillion units used in 1980 to 42 quadrillion in 2012. Despite some fluctuation between 1980 and 1995, there was a steady increase, which is expected to continue, reaching 47 quadrillion in 2030.
Consumption of energy from natural gas and coal followed a similar pattern over the period. From 20 quadrillion and 15 quadrillion respectively in 1980, gas showed an initial fall and coal a gradual increase, with the two fuels equal between 1985 and 1990. Consumption has fluctuated since 1990 but both now provide 24 quadrillion. Coal consumption is projected to rise to 31quadrillion in 2030, whereas after 2014, natural gas is forecast to remain stable at 25 quadrillion.
In 1980, energy from solar/wind, nuclear, and hydropower was the least-used, with only 4 quadrillion. Nuclear has risen by 3 quadrillion, and solar/wind by 2. Since 2005, hydropower has fallen back to the 1980 figure. It is expected to remain approximately constant through 2030, while the others are projected to rise gradually after 2025.
Overall, fossil fuels will remain the chief energy source for the US, with a little bit of hydroelectric, nuclear and a smidgen of renewables like wind and solar.
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