Information below from the OEP web site: www.nh.gov/oep/index.htm
Renewable energy property tax exemption. NH RSAs 72:61-72 permit cities and towns to offer exemptions from local property taxes for certain renewable energy installations. These include solar thermal (for example, to heat water), solar photovoltaic (to generate electricity), wind (to generate electricity) and central wood-fired heating systems (not stoves or fireplaces).
If your city or town does not currently offer such exemptions, see procedures for adopting local property tax exemptions. Note: Local officials may be unaware of exemptions, as the exemptions may have been adopted as long as 30 years ago.
If you live in a city or town that offers exemptions and you have an installation that qualifies, you may apply for an exemption by completing the NH Department of Revenue Administration.
OEP recommends that homeowners and municipal officials consult the NH Department of Revenue Administration with any questions regarding the renewable property tax exemption laws and their application.