Dominion North Carolina Power plans to buy electricity from a solar-power facility in North Carolina’s Outer Banks, the construction of the 1.4-megawatt photovoltaic solar power station is expected to start by March.

Dominion Resources Inc. in Richmond, has signed a 15-year agreement with Washington-based 510nano for a planned solar power station in Northampton County. The companies declined to disclose the contract terms.

The company said the North Carolina facility would be the largest solar-powered facility added to Dominion’s electric grid. It also is planning a 4-megawatt solar facility in Halifax County, 510nano plans to start building a plant in March on 7 acres in Northampton County, N.C., about 45 miles southwest of Franklin, and have it operating by the third quarter of this year, said Valjeanne Estes, project director for 510nano.

Dominion serves about 120,000 retail electric customers in northeastern North Carolina.

510nano has focused on sites in North Carolina for solar plants. The state offers a 35 percent corporate tax credit for renewable energy development that makes the project economical, Estes said.

She added that certain points in North Carolina have high levels of solar insolation, which is the amount of electromagnetic energy on the surface of the Earth – or how much sunlight reaches that spot. Locations in Arizona and the California desert, for example, also have high levels of solar insulation.

“So when you combine all of this, it makes the area good for this type of project,” Estes said.