We consider the problem of energy-efficient scheduling across multiple processors with a power-down mechanism. In this setting a set of $n$ jobs with individual release times, deadlines, and processing volumes must be scheduled across $m$ parallel processors while minimizing the consumed energy.When idle, each processor can be turned off to save energy, while turning it on requires a fixed amount of energy.For the special case of a single processor, the greedy Left-to-Right algorithm \cite{irani_left_to_right_soda_2003} guarantees an approximation factor of $2$.We generalize this simple greedy policy to the case of $m \geq 1$ processors running in parallel and show that the energy costs are still bounded by $2 \OPT + P$, where $\OPT$ is the energy consumed by an optimal solution and $P < \OPT$ is the total processing volume.Our algorithm has a running time of $\mathcal{O}(n f \log d)$, where $d$ is the difference between the last deadline and the earliest release time, and $f$ is the running time of a maximum flow calculation in a network of $\mathcal{O}(n)$ nodes.