Fossil Fuels

Consumption of fossil fuels is the dominant source (>97%) of greenhouse gases in Rhode Island. Because of the importance of this source and in order to give a more complete picture of the trends in fossil fuel emissions, this section of the inventory was compiled over a longer time period than required by the Workbook. Emissions data for the consumption of all fossil fuels were compiled for the 11-year period of 1986 – 1996, based, with one exception, on the Energy Data Report for Rhode Island for 1996, provided by the Energy Information Agency (EIA). The EIA reports fuel consumption by sector (residential, commercial, industrial, transportation and electric utility), and within each sector by fuel type. Following Workbook procedures, these data were converted into metric tons of carbon equivalents (MTCE) for all emissions.

The Fossil Fuel Emissions Table lists emissions by sector for 1990 and 1996, and accompanying figure shows the eleven-year trends in emissions by sector. Note that 69% of the increased emissions between 1990 and 1996 result from a nearly 600% increase in emissions from electric utilities. Note that this section of the inventory reports only carbon dioxide emissions. Emissions of nitrous oxide and methane (from mobile sources) are reported separately.

	1990	1996	1990-96
Sector	MTCE	MTCE	MTCE Increase	Increase
Residential	556,441	697,861	141,420	25%
Commercial	368,972	482,846	113,874	31%
Industrial	152,399	190,948	38,549	25%
Transportation	1,020,868	1,071,085	50,217	5%
Electric Utility	128,741	880,929	752,188	584%
Total	2,227,422	3,323,669	1,096,248	49%

Emissions for 1990 have particular significance, because that is the base year chosen for setting emissions reduction goals. The figure shows that 1990 emissions were significantly lower than any other year in the ’86 – ’96 period, a result of a temporary dip in distillate fuel consumption and a long-term decline in residual fuel use. (See the Emissions by Fuel Type figure). Emissions increases after 1990 result from a strong increase in use of natural gas in the utility sector and a return to pre-1990 levels in distillate fuel use.

The only comprehensive source of fossil fuel consumption data available to us was that provided by the EIA. EIA data are compiled from surveys of the owners of distribution systems, and apparently are subject to significant uncertainty. In the two cases where we were able to obtain independent reliable data against which EIA data could be cross-checked (natural gas consumption by the industrial sector, and imported electricity), the EIA data were found to be seriously in error. We therefore caution that the data supplied in this section may have considerable uncertainty – however the EIA data are all that are available, and there is no option to using them.

Analysis of emissions from fossil fuel combustion for the period 1986 - 1996

Because of the dominance of the inventory by emissions from fossil fuel combustion , we have prepared a variety of figures, showing the various combinations of fuel types and emissions sources. The charts below are linked to larger versions in the Fossil Fuel appendix. They show the breakdown by fuel type (Distillate Oil, Residual Oil, Gasoline, Diesel Fuel, Natural Gas) within five sectors of the economy (Residential, Commercial, Industrial, Transportation, Utility) (the right column) and within three fuel types, a breakdown by economic sector (the left column).

The EIA listed fuel consumption by independent power producers in the Industrial sector. Given the utility restructuring that has occurred in Rhode Island, this categorization no longer is appropriate. Ocean State Power (OSP) began production in 1991, and was the only significant independent power producer in Rhode Island in the ’86 – ’96 time period. We obtained consumption data directly from OSP but when we attempted to subtract the OSP data for natural gas consumption for 1992 from the industrial section, the OSP consumption was larger than the EIA total. We consulted with Roy Kass in the Natural Gas Section of EIA, and he was kind enough to supply us with natural gas consumption data for the industrial sector, excluding OSP consumption. These are the data we report for industrial natural gas consumption. We note that the report for the industrial sector still includes consumption by Pawtucket Power, a relatively small independent supplier, contributing approximately 1% of the electricity Narragansett Electric delivered in 1996. We added the natural gas and oil consumption reported to us from OSP into the EIA utility consumption data, and the totals are what we report for utility consumption.

Carbon dioxide emissions from the consumption of fossil fuels