Determine the cost $($$$/1000$ kg$)$ of producing low$-$pressure $($LP$)$ steam $($along with power

production$)$ using a natural gas fuel source. Assume that steam is produced at the highest pressure

$($HP$)$ level, and consider the specific case wherein this HP steam is let down from the high$-$pressure

header to a low pressure header $($to produce LP steam$)$ through a turbine, thereby generating

electrical power in the process.