Pie Charts

The pie charts below show the energy sources of a power plant in electricity generating in \(2000\) and \(2020\) , respectively.

1. Given that in \(2000\) , the energy sources used by the power plant in the order of Coal \(:\) Hydropower \(:\) Wind Energy \(:\) Oil is \( 13:2:1:4\) , find the values of \(w\) , \(x\) , \(y\) and \(z\) , respectively.
2. From the pie chart, find the ratio of the energy source used by the power plant in the order of Coal \(:\) Hydropower \(:\) Wind Energy \(:\) Oil in \(2020\) .
3. Given that the annual energy consumption in electricity generating of the power plant in \(2020\) is twice that of the power plant in \(2000\) , find the percentage change of energy consumption by each energy source, respectively, from \(2000\) to \(2020\) , correcting your answer(s) to \(3\) significant figures if not exact.
4. It is known that coal and oil are highly polluting traditional fossil energy sources, while hydropower and wind energy are clean energy sources. From the perspective of environmental protection, make one comment on the energy sources used by the power plant from \(2000\) to \(2020\) .