The EIA released the latest edition of their Electric Power Monthly on November 27th, with data for September 2018. The table above shows the percentage contribution of the main fuel sources to two decimal places for the last two months and the year to date.
In September, as usual for this time of the year, the absolute amount of electricity generated declined with the mid-summer demand for air conditioning falling away. Coal and Natural Gas between them, fueled 62.64% of US electricity generation in August, with the contributions from most other major sources edging up slightly. The contribution from Natural Gas was essentially flat at just over 40%, down from 40.19% in August, despite the decrease in the amount generated from 164,954 GWh to 142,745 GWh. Generation fueled by coal decreased from 115,218 GWh to 96,743 GWh, resulting in the percentage contribution falling from 28.07% to 27.12%. The amount of electricity generated by Nuclear plants decreased from 72,282 GWh to 64,725 GWh with the resulting contribution actually rising from 17.61% to 18.14% in September. The amount generated by conventional hydroelectric fell from 21,398 GWh in August to 18,663 GWh in September with resulting contribution remaining essentially flat at 5.23% as opposed to 5.21% in August. The amount generated by wind fell from 19,507 GWh to 17,991 GWh with the resulting contribution rising from 4.75% to 5.04% in September. The estimated total solar output fell from 10,000 GWh to 9,153 GWh with the resulting contribution rising from 2.44% to 2.57%. The contribution of zero carbon or carbon neutral sources rose from 30.93 in August to 32.01% in September. It is interesting that the contributions from Natural Gas and Coal are almost exactly interchanged from the beginning of the period covered by the graph up to September 2018.
The graph below helps to illustrate how the changes in absolute production affect the percentage contribution from the various sources.
The chart below shows the total monthly generation at utility scale facilities by year versus the contribution from solar. The left hand scale is for the total generation, while the right hand scale is for solar output and has been deliberately set to exaggerate the solar output as a means of assessing its potential to make a meaningful contribution to the midsummer peak. In September 2018 the output from solar at 9,153 GWh, was 3.36 times what it was four years ago in September 2014. It is now safe to say, this year solar energy peaked in June, the month of the summer solstice with 10,869 GWh generated for the month.
The chart below shows the monthly capacity additions for 2018. In September, Natural Gas contributed 33.58 percent of new capacity. With 45.78 percent of new capacity coming from Wind and Solar contributing 20.25 percent, Natural Gas, Solar and Wind made up 99.61 percent of new capacity in September. The only capacity added that was not fueled by Natural Gas, Wind or Solar was three battery installations, one each in the states of Texas, Michigan and Massachusetts. In September 2018, the total added capacity reported was 1,459.1 MW, compared to the 515.4 MW added in September 2017.
The chart below shows the monthly capacity retirements so far for 2018. The scale on the Y axis has been adjusted to start at 20% since there is no month in which coal capacity was retired where the proportion of coal capacity retired was less than that figure and between January and June, the minor contributors were so small that, they are barely visible even with the scale starting at twenty percent. In September, the only retirements noted were gas turbines at a 117 MW Auburndale Peaker Energy Center in Florida and the 4.1 MW Hunterdon Cogen Facility in New Jersey, 607.7 of Nuclear capacity at Oyster Creek in New Jersey and 294.4 MW of Conventional Steam Coal at Edgewater in Wisconsin.
Following the report on the edition of the EPM with data for March, there was some discussion about coal consumption for the production of electricity. At the request of peakoilbarrel.com member Shyam, I am including a table of the top ten states in order of coal consumption for electricity production for September.