Flash memory power consumption
A flash chip requires power for either read or write access.  The power advantage of flash comes from it being non-volatile.  That is, it needs no power in order to retain the information on it, once programmed. How much power a flash chip consumes depends on what operation is being called.  A write takes about 60 mA at 3 V for up to 3 msec (MLC NAND) That will program a single 16K byte page.  

If you do not need large storage density, you can consider PCM memory.  It is faster than NAND and byte addressable.  For more detailed information go to a memory vendor;s website, such as Micron.com, Samsung.com and look for their publid NAND and PCM memory specifications.  these contain information on programming time, read time, how to address them, etc.