1. Question: How much energy does the plasma-arc use?
Answer: The plasma-arc facility uses approximately 40 megawatts of energy per hour. This is approximately one-quarter of the total output of hourly energy received from MSW.
2. Question: What will be the source of the plasma-arc energy?
Answer: The facility will receive its energy from its total output. For St. Lucie, it is expected that the 3,000 tons of MSW processed per day will create 160 megawatts of energy per hour. As stated previously, 40 megawatts will be used to power the facility and the remaining 120 megawatts will be sold to an Electric Utility.
3. Question: What does the energy source emit?
Answer: See question 5.
4. Question: Is the high heat of the plasma-arc being captured and utilized?
Answer: Because of the nature of a closed-loop system the heat will be captured and utilized both in the plasma gasification process and later in the production of steam.
5. Question: How are they going to combust the syngas to keep the emissions low?
Answer: There is no combustion during the gasification process. The Plasma-arc gasification process is a chemical reduction process that converts MSW from its original state to a glass-like aggregate solid at the bottom, and a synthetic fuel gas, also known as syngas, at the top.
Once gasification is over, the syngas is cleaned in a multi-step process, bringing it to levels near natural gas cleanliness. It is then compressed before being used as fuel for a gas turbine.
The gas turbine for this process is a modified natural gas turbine that mixes the cleaned syngas with air from the atmosphere, combusts the mixture and sends the hot gases through a turbine. The turbine spins an electric generator to produce electricity. The discharged hot gases are then passed through a heat recovery steam generator to produce more steam and to cool the hot gases. The cooler exhaust gases are then discharged into the atmosphere via a stack.
Emissions from this process are very similar to natural gas combined cycle plants which are considered to be 'clean' and are located and permitted all over the U.S., and for that matter the whole world.