How many petajoules in a bushel?
As anyone even peripherally involved in the biomass industry knows, there are a bewildering array of methods of measuring biomass and its value as a product:
- Sometimes biomass product is measured by volume—bushel, bale, board foot, cord, cubic yard.
- Sometimes its measured by weight or mass–tonnes, tons, kilos, pounds.
- Sometimes weight quoted is not the weight of the product as-is, but the weight it would be if it moisture were removed—bone-dry tons, oven-dry tons.
- Sometimes biomass is measured by the energy that can be extracted from burning it—british thermal units, MegaWatthour, petajoule.
So what?
There are many reasons for this proliferation. But the causes are less important than the effects.
- It’s confusing and, to outsiders, makes the market seem like a mess. As a result, drives away potential customers.
- Having multiple units of measure holds back commodifcation of the product, which in turn slows down the growth of the sector, and weakens biomass’ competitive ability against fossil fuels.
- Participants in Biomass Brokerage, and other biomass market forums, have difficulty comparing options. This increases transaction effort and tends to narrow search parameters. Those effects reduce financial benefits available to both buyer and seller.
In other words: It’s bad.
Our Preferred Product Units
In an attempt to our bit to help overcome these problems, we have two units of measure that we prefer to use (in order of preference):
- MegaWatthours (MWh) of net energy produced by burning the biomass.
- tonnes (t)
These are preferences, not requirements. If you would rather list with Biomass Brokerage in other units, that’s no problem at all. We can do the conversions behind the scenes. Most of these conversion ratios are standardized. A good web resource for this is Online Conversion.
Why these preferences?
- The primary (although not the only) market for biomass trading through Biomass Brokerage is heat production. As a result, the amount of energy actually produced by the biomass when it’s combusted is the most crucial measure. It’s the best way we have to “compare apples to apples” when comparing price between multiple biomass sources.
- Tonnes is the most common unit by which biomass is sold currently. Although not all tonnes of biomass produce the same amounts of energy, it is still possible to use energy conversion estimates to get from tonnes to MWh.
Standard Conversion Ratios
| units | unit name(s) | symbol | units | unit name | symbol | notes | ||||||||||
| 1,000 | kilowatthours | kWh | = | 1 | megawatthour | t | ||||||||||
| 1 | ton / short ton / US ton | tn | = | 0.907 | tonnes | t | ||||||||||
| 1 | long ton / UK ton | lt | = | 1.016 | tonnes | t | ||||||||||
| 1 | 40-pound bag | = | 0.018 | tonnes | t | |||||||||||
| 1 | petajoule | PJ | = | 277,778 | megawatthours | MWh | ||||||||||
| 1,000,000 | British thermal units | Btu | = | 0.293 | megawatthours | MWh | ||||||||||
| 1 | tonne moist biomass @15% moisture | = | 0.85 | bone dry tonnes | [4] |
Numbers in this table are rounded for presentation. When used in calculations for trades, do do not round these numbers.
There are, of course, many more conversion ratios needed for Biomass Brokerage than the ones listed here. We use Online Conversion when needed. If there is a particular conversion ratio you need and it’s not listed here, email us and we’ll provide you with the one we use.
Default Conversion Ratios We Use
The table of conversion ratios listed above are standardized. Unfortunately, this is not true for all biomass conversion ratios. Not all biomass is created alike.
The biggest problem is that biomass varies by the amount of moisture in it, which greatly affects both weight and net energy available to extract. There are also other, secondary issues, including how tightly a product is packed when it is sold by volume.
We use a series of estimated conversion ratios to manage these problems.
| units | unit name(s) | symbol | product | units | unit name | symbol | notes | |||||||||||
| 1 | tonne | t | wood chips (dry) | = | 3.5 | megawatthours of heat energy | mWh | [1] | ||||||||||
| 1 | tonne | t | cordwood (dry) | = | 4.1 | “ | mWh | [1] | ||||||||||
| 1 | tonne | t | wood pellets | = | 4.8 | “ | mWh | [1] | ||||||||||
| 1 | tonne | t | straw @15% moisture | = | 4.0 | “ | mWh | [2] | ||||||||||
| 1 | cubic yard | y3 | wood chips (dry) | = | 0.121 | tonnes | t | [3] | ||||||||||
| 1 | cubic yard | y3 | sawdust (dry) | = | 0.1375 | tonnes | t | [3] | ||||||||||
| 1 | cord / full cord | firewood | = | 18 | megawatthours | MWh | [5] |
If your product tests with better conversion ratios that those listed here, email us. We’ll assess your data, and adjust our ratios when dealing with your product.
If you don’t have testing data, you can also email us, and we’ll arrange for a lab to do your testing for you. As you would expect, Biomass Brokerage cannot pay for the cost of this testing.
If you know of other good sources for these conversion estimates, again, email us. We would prefer to rely on either verified testing data or, failing that, multiple credible sources. We’ll adjust our numbers as appropriate.
Our Preferred Currency Units
Compared to converting biomass ratios, converting currency ratios is straightforward; currency exchange rates are public and, compared to biomass, are not subject to much debate.
Our home currency is the Canadian dollar (CAD), but are happy to do exchange rate conversions for you. The currencies we’re currently able to use are listed here.
If there is another currency you prefer to use in your listings, email us and we’ll do our best to include it.
1. Biomass Energy Centre, UK Forestry Commission “Typical calorific value of fuels”↩
2. Teagasac, National Development Plan “Straw for energy”↩
3. Oregon Department of Environmental Quality “Measurement Standards and Reporting Guidelines”↩
4. Forest Business Network “Green Ton Converter”↩
5. Superintendents Technical Association “Energy Conversion Factors”↩