I do not think that the general public understands how much improvement there has been to New York State’s air quality and how big the emissions reductions have been. This is a summary of the trend of SO2, NOx and CO2 since 1999 in New York State and it shows extraordinary improvements. Later, I will prepare a summary of the changes to the air quality measurements which also show big improvements.
I have to apologize for my inability to incorporate tables and graphs in the body of a WordPress blog post. If I had that ability then this post would be a heck of a lot easier to read. Instead I offer three alternatives. Each of the figures and tables is available by links in the following post. I also have prepared a version of this post and you can view NYS Air Pollution Emission Status Summary as a pdf document. Finally that document, three spreadsheets with the data, tables and graphs, and a detailed documentation summary of the data processing analysis are available at the NY Pragmatic Environmentalist dropbox.
The emissions and operating data used for this summary were downloaded from the EPA Clean Air Markets Division Air Markets Program Data website. The website includes a query tool that I have used for years to extract specific data from national emission monitoring programs. For this analysis I downloaded SO2, NOx and CO2 emissions data, operating time, heat input and load data as well as unit-specific information on fuel use and unit type so that I could show what changes caused the emissions reductions. Because this is a New York-centric blog I primarily focused on New York emissions.
Figure 1 NYS SO2 Emissions by Fuel Type documents the annual SO2 emissions from 1998 to 2017 by the primary fuel type reported to EPA. In 1998 SO2 emissions totaled 309,775 tons and in 2017 were only 2,561, a 99% reduction. Table 1 EPA CAMD Data New York State Air Pollution Emissions from All Program Units presents the emissions totals and includes the coal-firing totals. It turns out that reductions in coal-firing and residual-oil firing account for the reduction in SO2 mass. New York is unique in that there are five relatively new large residual oil-fired boiler units in the state. Although there were changes in the limit of sulfur in fuel the primary driver for the reductions was the cost of oil relative to natural gas coupled with the fact that there is essentially no SO2 emitted by natural gas firing. At this time these units survive because they can provide 1000s of MW when necessary and their operational costs are low enough that the payments to be able to provide that capacity are sufficient to be viable. Note, however, that they cannot reduce emissions much more because they still have to run a couple of times a year to prove that they can provide capacity. Coal-firing units in New York were older and were required to install extensive controls over this period to continue to operate. The cost differential between natural gas and coal was the final blow to viability and for all intents and purposes only one facility remains operating today. Governor Cuomo has proposed regulations to eliminate coal burning at even that unit by 2020. These data suggest the de minimus level of future SO2 emissions will be around 1,000 tons per year.
Figure 2 NYS NOx Emissions by Fuel Type documents the annual NOx emissions from 1998 to 2017 by the primary fuel type reported to EPA. In the peak year of 2000 NOx emissions totaled 101,635 tons and in 2017 were only 11,253, an 89% reduction. The coal and residual oil units were also the largest sources for NOx so they account for most of the reduction. On the other hand there still are significant NOx emissions from natural gas firing so the reductions are not as large. Eliminating coal firing will drop emissions another 2,770 tons from 2017 levels. Further reductions will come from replacing older, higher emitting units with new cleaner ones. If I had to guess on a future de minimus level it would be around 7,000 tons per year.
Figure 3 NYS Statewide SO2 and NOx Rates documents the changes in annual emission rates (lbs/mmBtu) over the same period. The reason for these changes is the same as the mass changes. Keep in mind that mass emissions are a function of these rates and the operating levels. If there is more demand on fossil-fired units then they will emit more. Of course, if renewable energy reduces the need for fossil-fired units or if demand for electrical energy goes down due to energy efficiency efforts then mass emissions will go down.
CO2 emissions are a bit complicated. There are two CO2 data sets included: one from the Regional Greenhouse Gas Initiative (RGGI) program units and the other from all programs. In New York there are some small peaking turbines that are not presently included in RGGI. Unfortunately the annual emissions are not directly comparable because units that are not affected by RGGI do not have to report annual emissions only the ozone season (May through September). Also note that the RGGI CO2 Allowance Tracking System (COATS) data system also provides annual numbers for the RGGI only units and those numbers are the same as the RGGI only units from CAMD. Figure 4 NYS CO2 Emissions by Fuel Type lists the annual CO2 emissions from 1998 to 2017 by the primary fuel type reported to EPA. Table 2 EPA CAMD Data NYS Air Pollution Annual Emissions from RGGI Program Units lists the annual emissions from these units. These data show that CO2 emissions reductions to date have been caused by fuel switching but importantly there isn’t much left to switch. As a result, future CO2 emission reductions will be more difficult.
In addition to annual market trading programs there are trading programs that run from May 1 to September 30 for NOx emissions to reduce ozone. Figure 5 NYS Ozone Season NOx Emissions shows the Ozone Season NOx emissions from 1999 to 2017 by the primary fuel type reported to EPA. In 1999 NOx emissions totaled 47,314 tons and in 2017 were only 5,533 tons, an 88% reduction. Figure 6 NYS Ozone Season NOx Rate documents the changes in ozone season emission rates (lbs/mmBtu) over the same period. The state-wide NOx rate during the Ozone Season in 1999 was 0.202 lbs per mmBtu and was 0.053 in 2017, a 74% reduction. Similar to the annual numbers these reductions are primarily the result of fuel switching. Finally Table 3 New York State Ozone Season NOx Mass by Unit Type lists the Ozone Season NOx mass, heat input and NOx rate values sorted by major unit types: boilers, combined-cycle turbines and simple cycle turbines.
These trends show that New York State has done a superlative job reducing emissions. There also are implications for future air pollution control programs in these data. Any future reductions simply cannot be as effective because the current emissions are so low. In addition, any program that claims air pollution emission benefits for reducing CO2 must recognize the current low rates and mass emissions or those benefit estimates are higher than appropriate.