A simple traversable wormhole violating energy conditions only at the Planck scale

We present a simple static spacetime which describes a spherically symmetric traversable wormhole characterized by a length parameter $l$ and reduces to Minkowski in the limit $lto 0$. The wormhole connects two distinct asymptotically flat regions with vanishing ADM mass and the areal radius of its throat is exactly $l$. All the standard energy conditions are respected outside the proper radial distance approximately $1.60l$ from the wormhole throat. If $l$ is identified as the Planck length $l_{rm p}$, the total amount of the negative energy supporting this wormhole is only $Esimeq -2.65m_{rm p}c^2$, which is the rest mass energy of about $-5.77times 10^{-5}{rm g}$.