I would expect that the reference is to thermal metering which is based on the potential to sell a thermal equivalent of SRECs (Solar Renewable Energy Credits). These in theory can be sold into the open market and purchased by utilities or other entities that need to certify that they meet renewable portfolio standards.
The process is somewhat complicated but here is my run at it. A political entity (currently a state) decides they want to force utilities or companies within the state, to use renewable power, they pass a law and force the utilities or businesses to prove that they need a certain percentage of the generation renewable. In the law there is a large penalty intentionally set high that the utility or company has to pay if they don't meet the percentage mandated by the law. The utilities or companies are unable or unwilling to install renewable generation (quite difficult to line up the renewable generation with the power demand) so they go out on the market and buy an equivalent number of SRECs for less than the large penalty. These SRECs are valuable and there is potential for abuse so there is usually third party monitoring and that third party is going to need to measure the actual output of a renewable producer. For solar this is easy, install a "revenue" meter on the output of the panels and read it once every so often and create SRECs based on the output.
Now try to apply that to thermal renewable energy, there is no good "heat meter" that could be put on the output of the wood stove or pellet stove, it would be quite difficult to figure out how much heat goes into the room versus up the stack. Thus most programs look at fuel input and assume an efficiency of the fuel input to put useful heat into a building. Unfortunately its easy to play games with fuel input if its based on receipts for bags of pellets or number of cords bought and how to handle the guy who cuts his own wood is another can of worms. Thus the opportunity is to measure actual fuel input into the stove. For wood there is no auger feed but for pellets there is. The auger approach is the simplest, assume for a given auger speed that a certain quantity of fuel goes in the stove and apply an assumed efficiency to the stove to calculate a useful btu output. The alternative concept that the OP appears to be researching is rather than measure auger input, come up with a method of weighing the stove and then calculating how much fuel is added on a continuous basis. This is particularly valuable for someone burning wood as it would account for the actual weight of wood being put in the boiler. Accounting for ash generation could be tricky but there could be a "tare" function that resets the base stove weight when the stove is not burning. There is also the fundamental problem that different pellets have different btu ratings and wood has different moisture contents. Thus there may be an incentive to run a cheaper low btu pellet as the owner would not get extra credit for high btu pellets. There would be a disincentive for wood users to burn dry wood as the wet wood is heavier and therefore they would get more credits for burning wet wood unless the assumed boiler efficiency was somehow measured with a continuous monitoring system (basically continuous CO, O2 and stack temperature measurement)
Do note for boiler systems its a heck of lot easier, measure the flowrate of water into the boiler and the inlet and outlets temps. The result of some basic math would be a thermal output that could be reported on a BTU meter and read periodically . Of course there is then a far more intense debate available on the thermal quality of these btus. Think of it this way, I come up with a way to heat 10000 pounds of water from 70 degrees to 71 degrees. I get roughly 10,000 btus credit but for most folks the 71 degree water is too cold to do much heating. The alternative is to heat 100 pound of water from 70 to 170 degrees. This is useful for those with convective or radiant heat but as far as the btu credit its the same 10,000 btus. Take this down to the con man side and a power plant has to reject heat to generate power either via a cooling tower or with river or ocean water. They are heating millions of pounds of water a couple of degrees but the water is probably 40 degrees. Thus they can claim a large credit for creating thermal energy which is basically useless, hats why they are heating up the local river or just pumping heat in the air via a cooling tower. So the law is going to have to factor in the usefulness of the BTUS generated as well as quantity. This process is ripe for political maneuvering and abuse.
Europe has a carbon credit market that runs similar to the SREC market, it has been a failure since the beginning as many folks have figured out how to game the system with far more complex logic than I laid out. New England has the REGGI carbon market for utilities which effectively is a carbon tax with some of the proceeds going back to states with the intention to support residential energy savings programs, in reality these funds have been scalped by many states for other purposes and even the renewable programs have been tainted with cronyism in many areas where politically connected suppliers get exclusive access to the funds. I expect the thermal REC market is also ripe for abuse and I expect entrepreneurs and wall street are already looking to game the system.
. They are after all Maine and NHs renewable resource (ask any gardener).
