Very good piece, very good. I like the art work, too. Two minor points You used the EJ unit as if readers are all familiar with it, but I had to look it up, learned that there are about 1050 J/btu, then realized I have no idea of the units by which to measure world energy conversion and therefore no idea of how 50 EJ from biomass compares to some other energy conversion process, e.g. PV solar electricity in a certain future year. Could you give readers such a comparison?
The question of burning waste forest products from a managed young forest in which every tree felled has a seedling planted by the stump has bugged me for months. Is it C neutral or not? You point out that burning wood waste empties a sink. When I asked this of an expert who was kind enough to reply to the email equivalent of a cold call, he wrote back that it is C-neutral "because the log would eventually have rotted." [and thus given up its CO2 to the air over some years]. From his reply I infer that the only way wood dropped to the ground can be a true long-term sink is when it's permanently underground, becoming soil. Burning forest product waste for fuel can only be seen as C neutral when the forest is managed by the best available methods, which may be more theoretical than real.
Please remind me, Steve, how I can share your excellent blogs with friends who are not subscribers
EJ: yes, I wish I had been able to say more to put these figures in perspective. It's tricky because the conversion factors from one form of energy to another are unclear (to me, at least). I _think_ that when a source says that biomass can provide a certain number of EJ of energy, that represents the heat which would be emitted when burning that biomass. However, this is already a fuzzy concept, because I don't know whether they're taking into account the energy required to gather, transport, and process the biomass before burning (probably not?). Then if you're using that biomass to generate electricity, you need to discount for energy loss entailed in that conversion, which will be substantial. Even if you're using it for heat – say, to heat a building, or power some industrial process – I'm not sure whether one joule of (say) wood pellets can be used as efficiently as one joule of coal or natural gas.
For all these reasons, I didn't try to go beyond this one brief note in the post:
> For perspective, the first data point of 63 EJ per year [estimate for sustainable waste biomass] is equivalent to roughly 10% of global energy usage in 2020 [footnote: This is a rough estimate, potentially failing to take into account conversion losses and other important factors.]
Also, footnote 1 notes that some net zero scenarios for 2050 show biomass producing roughly 25% of total world energy usage, though that 25% comes from me comparing numbers that may not be comparable, for the reasons noted above, and hence may be off by quite a bit. (And, as I explain in the post, I don't believe that we should or will use as much biomass as contemplated in those scenarios.)
As for your question regarding managed forests: it depends on the circumstances – what sort of land is the forest grown on, what would be taking place on that land if it were not being farmed for biomass, etc. But I think the reasonable default way to think about it is that the land could otherwise be allowed to settle into long-term forest growth. A maturing forest should hold more carbon than a forest which is repeatedly being harvested (and hence contains only saplings some of the time, as well as not supporting the rich aboveground and belowground ecosystems of a mature forest).
As for sharing the blog: the blog is open to all, so just send them a link to the post you'd like to share, or https://climateer.substack.com/archive to give them a list of historical posts.
It's unlikely any forests are "managed" optimally. Whether burning forest product waste can truly be carbon-neutral is more a thought experiment than a real-world consideration, especially when the emissions involved in creating the waste (i.e. felling the trees, de-branching them and transporting the waste to the burn site) are counted. I have shared your blog on twitter and a slack group.
Very good piece, very good. I like the art work, too. Two minor points You used the EJ unit as if readers are all familiar with it, but I had to look it up, learned that there are about 1050 J/btu, then realized I have no idea of the units by which to measure world energy conversion and therefore no idea of how 50 EJ from biomass compares to some other energy conversion process, e.g. PV solar electricity in a certain future year. Could you give readers such a comparison?
The question of burning waste forest products from a managed young forest in which every tree felled has a seedling planted by the stump has bugged me for months. Is it C neutral or not? You point out that burning wood waste empties a sink. When I asked this of an expert who was kind enough to reply to the email equivalent of a cold call, he wrote back that it is C-neutral "because the log would eventually have rotted." [and thus given up its CO2 to the air over some years]. From his reply I infer that the only way wood dropped to the ground can be a true long-term sink is when it's permanently underground, becoming soil. Burning forest product waste for fuel can only be seen as C neutral when the forest is managed by the best available methods, which may be more theoretical than real.
Please remind me, Steve, how I can share your excellent blogs with friends who are not subscribers
EJ: yes, I wish I had been able to say more to put these figures in perspective. It's tricky because the conversion factors from one form of energy to another are unclear (to me, at least). I _think_ that when a source says that biomass can provide a certain number of EJ of energy, that represents the heat which would be emitted when burning that biomass. However, this is already a fuzzy concept, because I don't know whether they're taking into account the energy required to gather, transport, and process the biomass before burning (probably not?). Then if you're using that biomass to generate electricity, you need to discount for energy loss entailed in that conversion, which will be substantial. Even if you're using it for heat – say, to heat a building, or power some industrial process – I'm not sure whether one joule of (say) wood pellets can be used as efficiently as one joule of coal or natural gas.
For all these reasons, I didn't try to go beyond this one brief note in the post:
> For perspective, the first data point of 63 EJ per year [estimate for sustainable waste biomass] is equivalent to roughly 10% of global energy usage in 2020 [footnote: This is a rough estimate, potentially failing to take into account conversion losses and other important factors.]
Also, footnote 1 notes that some net zero scenarios for 2050 show biomass producing roughly 25% of total world energy usage, though that 25% comes from me comparing numbers that may not be comparable, for the reasons noted above, and hence may be off by quite a bit. (And, as I explain in the post, I don't believe that we should or will use as much biomass as contemplated in those scenarios.)
As for your question regarding managed forests: it depends on the circumstances – what sort of land is the forest grown on, what would be taking place on that land if it were not being farmed for biomass, etc. But I think the reasonable default way to think about it is that the land could otherwise be allowed to settle into long-term forest growth. A maturing forest should hold more carbon than a forest which is repeatedly being harvested (and hence contains only saplings some of the time, as well as not supporting the rich aboveground and belowground ecosystems of a mature forest).
As for sharing the blog: the blog is open to all, so just send them a link to the post you'd like to share, or https://climateer.substack.com/archive to give them a list of historical posts.
Thank you, Steve, for follow-up on EJ.
It's unlikely any forests are "managed" optimally. Whether burning forest product waste can truly be carbon-neutral is more a thought experiment than a real-world consideration, especially when the emissions involved in creating the waste (i.e. felling the trees, de-branching them and transporting the waste to the burn site) are counted. I have shared your blog on twitter and a slack group.