More coal used in electricity generation in 2013 compared to 2012 accompanied an increase in emissions.
Coal went from contributing 42.1 percent of the region's energy in 2012 to 44.4 percent in 2013. With that and a slip in natural gas contributions came increases in carbon dioxide, nitrogen oxide and sulphur dioxide associated with power generation.
But longer-term, the electricity grid for 13 states including Ohio, Pennsylvania and West Virginia could handle a significant increase in wind and solar power with little disruption, a new report found.
The grid for those 13 states could handle wind and solar power producing 30 percent of its capacity by 2026 without "any significant issues," according to the report from PJM Interconnection.
In the report, wind and solar displaced power generation from mainly the coal and natural gas sectors.
Of the new electricity coming from wind and solar, on average, 36 percent replaced coal power and 39 percent displaced gas-fired power, according to the report. The rest of the displaced power generation came from imports or planned projected increases in exports.
A wholesale electricity market and grid manager for those states, PJM hired GE Energy Consulting and others to examine wind and solar data and public and proprietary information about the grid for 2004, 2005 and 2006.
The report incorporated PJM's system upgrades planned for 2016 and 2017 and accounted for the cost in making adjustments to those plans to include seasonal variability in wind and solar power generation.
What inconsistencies there were in the projected availability of wind and solar power came from "localized congestion" rather than any issue with the PJM transmission system, according to the report, although recommendations included carrying more reserves to answer fluctuations in availability.