Coal plays a vital role in electricity generation worldwide. Coal-fired power plants currently fuel 37% of global electricity¹. In some developing countries, coal power plants are main electricity source. In United states, coal-fired power plants contribute about 30% of the total electricity in 2014. Coal is more popular in the east coast, and still accounted for at least 50 percent generated electricity in 13 states in the east.

Location and plant capacity of coal-fired power plant in united states²

  Comparing to other renewable sustainable energy, powering by coal may cause critical environmental issue. Water and air are heavily negatively impacted in the process from coal mining to burning coal into energy: coal mining can contaminate nearby rivers and lakes, heavy metal coal ash could increase cancer risk and so on. Today, we are going to talk about the effect of sulfur in coal.

  Sulfur is naturally in the coal. The percentage of sulfur could be varied around 0.3%~1% composition of the coal. When coal is burning in the power plan, Sulfur react with oxygen and produce sulfur dioxide. Sulfur dioxide escapes from the chimney of the power plant and blends into the atmosphere with water vapor. When the sky is clear or when clouds occupy only a few percent of tropospheric volume, sulfur dioxide could react with the hydroxyl radical oxygen and many water, and form sulfuric acid. Sulfuric acid dissolves in the water vapor in the cloud and later produce acid rain, which is harmful for human health, adverse effects on ancient rock buildings and the environment.

Rather than emitting sulfur dioxide into air and turn into acid rain, the sulfur dioxide is fixed to the fertilizer

  Now we know that sulfur dioxide is harmful if it escapes to the air, so is there a way that we could capture it and reused it? The answer is yes, Charah Inc, a Louisville, Kentucky based company are helping the local coal-fired power plants to collect the sulfur by turning it into gypsum³. And recently Charah Inc, find a way to turn  highly pure gypsum into sulfur and calcium rich fertilizers. These pelletized fertilizer is easy to use and perfect for growing plants with high sulfur uptake such as corn and alfalfa. In this way, sulfur from the coal could bypass the atmosphere and fixed into the soil for plant grow purpose.

Pelletized fertilizer³

  This a very brilliant way to turning a potential hazard to a valuable product. However, we should not forget that this is only fixing one hazardous component from coal-fired process. The contaminations from coal mining is still unsolved. Using Coal as our energy source is not a substantial way to obtain power. In near future, at least in united states, we could find a way to generate all the power using renewable energy.

1. Coal & electricity (2018)
2. Mapping how the United states generates its electricity (2018)
3. Converting Sulfur from Flue Gas into Fertilizer (2018)