OK... Coking Coal.
This coal has more to it than just calorific value (CV). Coking coal also needs fluidity, swell, and strength (following coking). So a high fluidity but modest CV coal could be more valuable than one with a higher CV but lower fluidity. There are also deleterious elements such as sulphur that potentially reduce the value of coking coal. Coking oven operators will blend several coals together to optimise production and minimise the input coal costs.
Thermal Coal...
In current parlance this term refers to the sub-bituminous coal of the global seaborne market. Again this covers a broad spectrum of materials with the underlying value being the CV and specifically the AR (as received) as opposed to AD (air dried) CV. The CV of a coal is a result of its composition combined with the dilution and loss from the contained ash and moisture. Different CVs, ash and moisture contents, have an impact on the sale price for each shipment. Not all deleterious elements are an issue in thermal coals, for example some thermal coal users can also tolerate high sulphur levels if the boiler is set up to handle it (with a long term contract as is typical) which would not be acceptible in coking coals. In the simplest terms users of thermal coal are paying for the AR CV which is what heats their boilers.
In broader terms though "coal" covers material ranging from Peat through to Graphite (yes that trendy new material is actually a coal). At the lower end of the scale peat and lignite fall below "thermal coal", even though that is how they are promarily used, with anthracite and graphite at the high end above "coking coal".These additional coals are used as follows: Peat is most notably used as a fuel in Ireland. Lignite (or brown coal) is used for power generation and also in chemical processes to synthesis various elements. Lignite typically occurs in massive deposits and is very cheap to mine... but it also has a low CV and high moisture. Lignite is not usually shipped anywhere but is mined and fed directly into power stations at the mine gate (such as in the Latrobe valley in Victoria and the Ruhr region in Germany). Combining the mining with the power station has significant cost benefits - these systems can generate power in the low single digit cents per kWhr. Some lignites can also be used as feedstock for chemical processing including coal - to - liquid systems. Anthracite is used in some chemical and metallurgical processes as well as domestic heating as it burns very cleanly with high CV and little ash. Graphite is the only coal that does not see any thermal use as it doesn't burn readily. Graphite has a wide range of uses from the "lead" in pencils to brake linings to refractory mold release.
