CONCORD – Eversource customers are footing the bill for the company to pay $100 million over-market rate to buy energy from a Berlin biomass plant by 2020. But a spokeswoman for the plant’s manager said the 4-year-old Burgess BioPower plant provides more economic benefits than the cost of over-market rates. The power deal was part of a jobs vs. electricity cost debate played out early this decade when many state policy leaders backed the deal to help the North Country economy. “People made essentially a policy choice of trading ratepayer benefits against broader economic interests,” said Donald Kreis, the state’s consumer advocate. …”There’s a balancing act, no question about that,” Bradley said last week. “Rates are high in New Hampshire, and I think we have to be cognizant of that.”