Replacing Coal

Coal at coal fired plantHM3 Energy’s TorrB® briquettes provide direct coal replacement fuel, turning low-cost biomass into brittle, energy dense briquettes that can be used directly in a powder coal boiler without material modifications, due to these properties:

  • Water resistivity, which allows them to be shipped and stored without cover
  • Similar grindability as coal (45 on Hardgrove Grindability Index)
  • High energy density, with Btu slightly higher than western coal
  • No binders used during production or other impurities that affect performance of coal boiler during combustion
  • High bulk density for savings in shipping and handling costs

HM3’s TorrB® briquettes were test burned in Western Research Institute’s (WRI’s) coal boiler in 2017, with excellent results. WRI’s boiler is a 250,000 Btu/hr (73 kW) balanced-draft system designed to replicate a pulverized coal-fired utility boiler. TorrB® briquettes were easily ground prior to combustion, and the flame temperature was extremely steady for the duration of the test burn. This short slide presentation explains  why torrefied product can directly replace coal with no material modifications to the plant and the cost advantages of switching a coal plant to using TorrB® briquettes rather than raw wood pellets.

Coal-fired power plants provide approximately 30% of the electricity in the U.S. In 2017, there were 359 coal power units operating in the U.S. While many utilities are augmenting their sources for power with gas, solar and wind generation, they have significant capital invested in coal-fired power plants. Over the years coal has been an affordable, reliable fuel source ready to produce electric power 24-7. In recent years Renewable Portfolio Standards (FPS) and carbon taxation have changed the long-term cost calculations for coal power. Coal-fired plants are responsible for 35% of the  CO2 emissions in the U.S. They also have annual emissions of 46,000 tons of mercury, 3.1 million tons SO2 and 1.5 million tons NOx.

coal-fired electric generation plantWhether these plants plan to spend money on emission control, carbon capture, or both, they face significant costs for implementation. If they don’t do anything, they face significant taxation on their carbon emissions, or fines for polluting—perhaps even shutdown. Many are considering replacing coal.

Replacing Coal with Clean Energy

Utilities are replacing coal energy sources in the future, and they are reviewing all their options, including clean energy generation sources, such as solar, wind, nuclear, biomass or geothermal, as well as substantial construction costs for new gas-fired power plants. They need to maintain a certain amount of baseload capacity in their portfolios. Wind and solar, for example, cannot fully replace coal as energy sources for electric generation, as their energy streams are variable. On the other hand, gas-fired plants are still fossil-fuel based. Nuclear reactors are very expensive to build and pose safety concerns with operation and storage of waste materials.

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