System power up - solenoid valve

Hello guys,
I am working on an autonomous system in whitch I want to reduce power consumption the maximum possible for an autonomy of 1 year at least.
My system contains :
-Arduino pro mini 3.3v 8MHz.
-NRF24l01 3.3v.
-solenoid valve 6v-12v.

so can batteries do the work knowing that I am using the sleep mode for arduino and NRF ?
-Must I use a solar panel ?

I am waiting for your suggetions.

Latching solenoid valve? Solenoid duty cycle?

latching one with 4.6W 12V 250ma