New Hampshire’s interest in town centers may be partly due to PlanNH, a Portsmouth-based non-profit organization that every year helps a handful of communities envision what type of center best fits a city or town.

Plan NH, a partnership of development companies and design professionals, runs a series of charrettes, or intensive two-day design workshops, with members of a community to see what possibilities they can develop for town centers.

“We do these as a service to the communities, and I think we’ve done about 50 so far, ” said Bill Jean, president of the executive board for PlanNH, director of business development for the Amherst-based construction and development company Fulcrum Associates and a member of the Bedford Town Council.

Jean said each charrette begins with a listening session where Plan NH professionals gather with community members to hear what they think are the most important qualities of a town center. PlanNH members then develop ideas that are presented to the community.

“In some cases, this is the only way to provide this type of planning assistance to communities that can’t otherwise afford to pay for it,” said Jean, who added that each charrette is unique.

Both Plan NH, and its sister organization, Vibrant Villages, encourage smart growth principles such as high-density housing in mixed-use town centers that provide jobs and are served by public transportation. The goal is to preserve land and cut consumption of other natural resources, especially fossil fuels.

New Hampshire’s lack of public transportation and its towns that have a limited economic base makes some smart growth ideas almost impossible. However, high-density housing in town centers may be a solution for an oncoming population shift that the state may not be ready to accommodate.

Milford resident Lorinda Stickney said she and other residents in the town’s senior housing apartment complex value town centers like Milford because they are walkable communities where many of the things they want and need on a daily basis are within easy reach.

“We love the oval,” said Stickney, referring to Milford’s town green. “We come here every day, and we’re here for all the concerts.”

New Hampshire’s population of seniors is expected to double within the next 20 years, to roughly 26 percent of the state’s total population. Smart growth ideas may be one way for towns to accommodate this growing sector of their community.