It shall be the duty of the department of revenue, and it shall have power and authority:

   (1)   To have and exercise general supervision over the administration of the assessment and tax laws of the state, over assessors, boards of review, supervisors of equalization, and assessors of incomes, and over the county boards in the performance of their duties in making the taxation district assessment, to the end that all assessments of property be made relatively just and equal at full value and that all assessments of income may be legally and accurately made in substantial compliance with law.

   (2)   To confer with, advise and direct assessors, boards of review and county boards of assessment as to their duties under the statutes.

   (2a)   To prepare and publish, in electronic form and on the Internet, assessment manuals. The manual shall discuss and illustrate accepted assessment methods, techniques and practices with a view to more nearly uniform and more consistent assessments of property at the local level. The manual shall be amended by the department from time to time to reflect advances in the science of assessment, court decisions concerning assessment practices, costs, and statistical and other information considered valuable to local assessors by the department. The manual shall incorporate standards for the assessment of all types of renewable energy resource systems used in this state as soon as such systems are used in sufficient numbers and sufficient data exists to allow the formulation of valid guidelines. The manual shall incorporate standards, which the department of revenue and the state historical society of Wisconsin shall develop, for the assessment of nonhistoric property in historic districts and for the assessment of historic property, including but not limited to property that is being preserved or restored; property that is subject to a protective easement, covenant or other restriction for historic preservation purposes; property that is listed in the national register of historic places in Wisconsin or in this state’s register of historic places and property that is designated as a historic landmark and is subject to restrictions imposed by a municipality or by a landmarks commission. The manual shall incorporate general guidelines about ways to determine whether property is taxable in part under s. 70.1105 and examples of the ways that s. 70.1105 applies in specific situations. The manual shall state that assessors are required to comply with s. 70.32 (1g) and shall suggest procedures for doing so. The manual or a supplement to it shall specify per acre value guidelines for each municipality for various categories of agricultural land based on the income that could be generated from its estimated rental for agricultural use, as defined by rule, and capitalization rates established by rule. The manual shall include guidelines for classifying land as agricultural land, as defined in s. 70.32 (2) (c) 1g., and guidelines for distinguishing between land and improvements to land. The manual shall specify the evidence to be exchanged under s. 70.47 (7) (c) and (16) (c). The cost of the development, preparation, and Internet publication of the manual and of revisions and amendments to it shall be paid from the appropriation under s. 20.566 (2) (bm).