Sadly we have no hard-written specifications for such parameters.
Keep in mind that RUT240 has no Sleep functionality. Also, power consumption relies on specific applications. For example the more functionalities you have enabled at one given moment the more power consumption you will have.
Usually, our clients with Solar Power needs, measure one device on the field in a real situation.
Also to help improve the Watts consumed, the best option is to supply the lower voltage possible, in this case, it's 9V.