Coal Report Methodology

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Weekly Coal Burn Report Methodology (US)

The Genscape Coal Burn Report estimates the amount of coal burnt at a plant based on the plant’s measured output in MWh and a ratio of tons of coal combusted to MWh of electricity produced, the coal-burn ratio.

The coal-burn ratio is calculated using data published by the US Energy Information Administration (EIA) culled from form 906. The ratio is based on the average of the six most recent months of data published by the EIA.

The report is produced weekly based on the power generated during the previous 168 hours (7 days) ending at Thursday at midnight. The report is published on Friday mornings at 10 am eastern time. Should a holiday fall on a Friday, the report will be published the following Monday at the same time of day.

Week 1 will always start on January 1st and end on the first Thursday of the year. Week 52 will always end on December 31st.
Genscape currently measures electricity output at 115 coal-fired plants using patented technology. The measurements are stored in a database in real-time and are used to calculate the cumulative weekly output.

Should a plant’s output fall to less than 25% of nameplate capacity during any observation period, Genscape will set that plant’s coal burn estimate to zero. Coal burn estimates at low utilization levels are not sufficiently reliable to be included in the total coal burn figure.

Genscape rates its coal-burn estimates based on co-incidence of its calculated coal burn numbers with those reported to the EIA and the depth of data used for comparison. The table below shows the thresholds for confidence levels applied to the calculated data. The criteria for rating plants are listed below. All the criteria for a high confidence level have to be fulfilled for a plant to be

Avg variance
Variance volatility Sample size Confidence level

Less than 10%
Less than 10% 12 or more months High

Less than 30%
Less than 15% 7 or more months Moderate

Above 30% Above 15% Fewer than 7 months Low

Genscape regularly adds plants to its monitoring network and where not enough time has passed to provide sample data, the confidence level is less than high. A plant may thus move from low to moderate to high confidence as more data is accumulated.

Plants may also change confidence levels during the monthly adjustment to the most recent data published by the EIA. This can be due to better coincidence between observed and reported generation, or to increased consistency in the type of coal burned and therefore in the coal-burn ratio. A plant may also move down on the confidence scale.

In addition to publishing data by plant, Genscape also reports national, east and western totals, as well as totals by census division.