Gov. Scott Walker recently included a property tax exemption for manure digesters and other biofuel systems in his 2013-2015 budget. The rationale is to encourage local bioenergy systems. In June, the Wisconsin Department of Revenue estimated that 20 to 25 biodigesters in the state would qualify for the exemption. The exemption is controversial due to its impact on reducing local property values with some municipalities likely to have substantial impacts. Since a number of facilities are either municipally-owned and operated, or tax assessors have been undervaluing or not assessing these facilities, they were not contributing to tax values. An estimate by the Department of Revenue two years ago suggested that this exemption would reduce property values statewide by $25 to $50 million. State Senator Bob Jauch, D-Poplar, estimated that this exemption may reduce property values statewide by $800 million or more, shifting $16 million in taxes on biofuel system owners to other property owners.