\begin{aligned} & \text { Capacitance }=\mathrm{C}=\frac{\varepsilon_0 \mathrm{~A}}{\mathrm{x}} \\ & \text { Energy stored }=\mathrm{U}=\frac{1}{2} \mathrm{CV}^2 \\ & \mathrm{U}=\frac{1}{2} \frac{\varepsilon_0 \mathrm{~A}}{\mathrm{x}} \mathrm{~V}^2 \\ & \frac{\mathrm{dU}}{\mathrm{dt}}=\frac{1}{2} \varepsilon_0 \mathrm{AV}^2\left(-\frac{1}{\mathrm{x}^2}\right) \frac{\mathrm{dx}}{\mathrm{dt}} \\ & \frac{\mathrm{dU}}{\mathrm{dt}} \propto \frac{1}{\mathrm{x}^2} \end{aligned}