Characterization of the U.S. Industrial Commercial Boiler Population

4 HISTORIC TRENDS
4.1 Boiler Sales Trends
There are several sources of historic data on boiler inventories. These sources show that
sales of large boilers have been quite slow for almost 30 years. This also means that the
majority of the existing boiler inventory is more than 30 years old.
Figure 4-1shows the long-term trend in sales of watertube and firetube boilers larger than
10 MMBtu/hr for the years 1964-2003 based on data from the ABMA. The bulk of
boiler unit sales throughout the period has been the smaller, firetube boilers. However,
sales of these firetube boilers also have been generally declining throughout the period
shown, from about 3,000 per year in 1964 to about 500 per year in 2002. Sales of small
watertube boilers – 10 to 100 MMBtu/hr also declined slowly from 1964 through 1973,
then abruptly dropped to 100 to 150 units per year in the mid-1970s and continuing for
the next 25 years. This segment experienced a brief sales boom from 1997 through 2002.
The reason for this short sales increase is not clear but it seems to have passed.
Historic sales trends for larger watertube boilers (>100 and >250 MMBtu/hr) are shown
in Figure 4-2. Sales of these boilers also dropped dramatically after the 1974 energy
crisis and economic recession. Sales dropped from hundreds per year to dozens per year
and have not recovered except for a brief surge in sales of the 100 – 250 MMBtu/hr
boilers during 1999 to 2002. These sales were primarily for natural gas and waste heat
recovery boilers, possible related to the gas power plant construction boom during this
period.
Given the low sales over the last 30 years, the existing inventory is now quite old. Total
sales of boilers larger than 10 MMBtu/hr for 1964 to 2002 were 17,500 units and 1.3
million MMBtu/hr of capacity compared to a combined boiler inventory (including
nonmanufacturing boilers) of 56,000 units and 2.8 million MMBtu/hr of capacity in this
size range. The sales data for units larger than 10 MMBtu/hr suggests that 47 percent of
boiler capacity is at least 40 years old and 76 percent is at least 30 years old
shows the approximate age distribution for the combined inventory. Approximately 7
percent of the capacity is less than 10 years old, 8 percent is 10 to 20 years old, 10
percent is 20 to 30 years old, 29 percent is 30 to 40 years old and 47 percent is over 40
years old. Of the 1,350 very large boilers (>250 MMBtu/hr) about 900 are more than 30
years old.
Energy and Environmental Analysis, Inc. 4-1