I'm sorry I don't know the detail. I do know MLAT is providing coverage where traditional surveillance I.e radar cannot do so effectively and it's replacing radar because of cost advantages.
I suspect the sites are solar powered or are co located with other services that already have power on site. The MLAT sites also have a small footprint.
They are just a receiver with a small aerial with low power requirements. I don't know what the density requirements are but figure there are probably more cell phone towers per square area on average.