While looking on Halo Reach we saw a post about a map that we will be able to play in Halo: Reach Beta. The map is called Powerhouse.
Bungie describes the map as:
“Utility and economy spurred industry amidst these isolated and unforgiving badlands, but like all infrastructure facilities on Reach, this hydroelectric site is under the purview of the UNSC war machine. All threats to the continued, predictable operation of humanity’s final line of defense must be met with swift and decisive force.”