A note about tonnage and energy figures
It is customary for the waste treatment capacity of WTE plants in North America to be rated in terms of short tons per day. In Europe, metric tons per year is the typical metric for plant capacity. Maximum ratings of the furnaces are generally stated in metric tons per hour. The annual tonnage accounts for downtime of the incinerators for maintenance, while the daily and hourly tonnage values do not. The WTE database will store all plant ratings as metric tons per annum (year), and therefore the true annual capacity of American plants entered using tons per day will be inflated slightly, because it assumes that the facilities are running constantly through the entire year.
The same applies to energy figures, where American plants typically produce only electricity and are rated in terms of power (megawatts). This megawatt rating is usually the nameplate capacity and again does not account for maintenance or reductions in capacity. European plants usually produce heat as well and are often rated in gigawatt-hours per year (GWh/a) and this usually takes into account downtime and reductions from maximum capacity. The database stores the plant capacity as GWh/a.
A watt is a unit of power - how many lightbulbs/houses can the plant light up?
A watt-second (also called a joule) is a unit of energy - how long can I keep those lightbulbs/houses lit up?
There are no such units as a "megawatt per day" or "kilowatt per hour", or
"50,000 homes per day"
Electricity is billed in kilowatt-hours (kWh), not kilowatts or the ever-prevalent "kilowatts per hour"
kWh is not the same as kW/h
Last Modified: October 13, 2009. 13:13:45 pm
