Reducing Emissions
There are enormous environmental benefits in switching from coal-fired power generation to wood. This was one of the primary reasons why PSNH developed Northern Wood Power at Schiller Station in Portsmouth.

Reduction of Fossil Fuel Use
Every year, PSNH purchases about 400,000 tons of low-sulfur coal to fuel Schiller Station's three 50-megawatt steam boilers. Replacing a boiler with one designed to burn wood chips and other clean wood byproducts reduces coal burning by more than 130,000 tons of coal each year. The reduction in coal-fired energy is offset by an equivalent amount of cleaner, greener wood-fired energy.

Dramatic Reduction in Emissions
Northern Wood Power eliminates thousands of tons of emissions each year. PSNH's wood-fired boiler uses a state-of-the-art fluidized-bed system, which is a low-emission advanced combustion technology. Fluidized-bed systems use a heated bed of sand-like material suspended (or "fluidized") within a rising column of air. The scrubbing action of the bed material on the wood chips strips away the charred layers that normally form around the fuel. This vastly improves the efficiency of the combustion process.

The fluidized-bed boiler technology, along with the inherent environmental advantages of wood, burns fuel more completely and substantially limits the production of nitrogen oxides and other airborne emissions. Compared to its coal-burning boiler predecessor, the wood-burning boiler produces about 70 percent less nitrogen oxide (NOx) emissions, reduces mercury emissions by about 90 percent, and produces little particulate matter. The process also virtually eliminates sulfur dioxide (SO2) emissions-the major component in acid rain-reducing them by about 95 percent.

Maintaining Environmental Balance
Carbon naturally cycles through the atmosphere until it is captured and stored in trees and other green plants. When a tree dies and decays, the stored carbon is released back into the atmosphere. In contrast, the carbon stored in fossil fuels is isolated from the environment, and without human intervention (such as mining and drilling), it remains there. The process of burning coal and oil increases the net amount of carbon in the environment. Therefore, whole-tree wood chips and other biomass materials are considered "carbon neutral," meaning no additional net carbon is released into the atmosphere by burning wood.

Meeting Clean Air Goals
Replacing one of the boilers at Schiller Station with a wood-fueled boiler helped PSNH meet the requirements of the New Hampshire Clean Power Act. Northern Wood Power also helps the state meet federal clean-air standards and provides a cleaner, greener environment for all New Hampshire residents, now and for generations to come.