Turning tires into energy by pyrolysis

This picture represents less than a year's worth of tires from a community of 200,000 people

Ceres Associates

It is time we started visualizing solid waste as a profitable resource.

Let’s take a look at used tires for instance. According to Cal Recycle almost 45 million used tires are generated in California every year. Nearly 40 percent of those are either landfilled or incinerated. These numbers are generated by the State, and are likely to be a little generous on the side of recycling.

If we take the State at its word, about 18 million tires per year in California have no positive use. If all of those 18 million tires were delivered to gasification waste-to-energy plants, they would be able to produce about 10,000 megawatt hours of electricity. Using over-simplified conversion ratios, those tires could then produce enough energy to supply electricity to about 1,000,000 homes. Yet currently we simply dispose of that resource as though it has no value.

In pyrolysis waste to energy technology all of the steel from the tires will be recovered and resold in the recyclables marketplace, slightly lessening our need to import steel. There are approximately three pounds of steel per passenger tire. In California then, the 18 million waste tires generated every year would produce approximately 26,000 tons of steel, with the current rate for recycled steel at about $250 per ton.

With a continuous feed of tires, the 5 to 10 percent carbon char that is generated by a pyrolysis waste to energy system has a myriad of practical uses. The char can be sold to manufacturers to produce many commonly used products. Once again we note that using this technology we not only generate electricity and valuable commodities, but we have nothing left over to go to the landfill – zero waste.

The Arizona state government recently passed legislation that allows use of their enormous piles of waste tires to fill abandoned mines. Millions of tires that are being used to fill void space. If you can imagine the valuable resource the State is literally throwing down the hole.

Les Schwab is the nations leading retailer of tires. That company tells us that one passenger tire per year is generated for every person in the country: approximately 340 million used tires are currently generated in the United States per year. Many of the tires Les Schwab now generates are chipped and landfilled. They have to pay someone to do this for them, again tossing a resource down the hole.

There are many technology companies struggling to obtain funding to get their projects initiated and prove their value. Government is continually stressing that we have need for energy independence. Somehow, if we can manage to merge these two symbiotic needs, the country will greatly benefit.