$1$ kilowatt hour $\left(kWh\right)$ is equal to

$1$ kilowatt hour $\left(kWh\right)=\left({10}^{3}W\right)\times \left(3600 s)\right)$

$$\begin{gathered} =\frac{3.6\times {10}^6}{1.6\times {10}^{-19}}eV \left(\because 1 eV=1.6\times {10}^{-19}J\right) \\ =2.25 \times {10}^{25}eV \end{gathered}$$