Biomass, RHI etc.

[Dave2002]

In some parts of the UK HMG appears to be encouraging the use of burning wood pellets as a so-called "sustainable" initiative, and also provides incentives for doing so under the RHI (Renewable Heat Initiative).

This article suggests that this policy might be very misguided - https://e360.yale.edu/features/wood_..._co2_emissions

If done on a small scale, then burning wood (having been made into pellets) might be carbon neutral, as the carbon released would be reabsorbed by trees which could then go into a cycle of harvest etc.
However, the article suggests that a lot of the wood used for the UK and the EU comes from the USA - which is quite a surprise as that must also include transport costs. Additionally, the volumes of wood are large, and the wood is being taken from the wrong kind of trees.

This does suggest a significant misunderstanding of what renewable and sustainable means by those who shape this kind of policy in the UK.

I don't have enough information about this area to know whether use of stoves using wood pellets in the UK is in fact a really bad idea, but the claims for such use as "saving X tons of CO2" etc. might need to be examined much more carefully.

[Bryn]

Even back in the early 1970s, when I was working at the Centre for Overseas Pest Research, New Scientist ran an article warning of the carcinogenic properties of the smoke produced by wood-burning stoves, advising that in urban areas these were best totally avoided. At that time, the principal problem was the relatively low temperature at which the wood burns in such stoves. Much higher temperatures, and thus lower generation of the carcinogens, were found in bonfires.

[eighthobstruction]

https://theecologist.org/2018/apr/16/hardwood-forests-cut-down-feed-drax-power-plant-channel-4-dispatches-claims

https://www.dailymail.co.uk/news/art...sing-coal.html sorry for DAily Mail input

....and the HMG/HMRS are subsiding all this mismanagement....energy to harvest wood-energy to make pellets - ship to Europe - move around Europe....a lot of info to say that the harvesting sites are not being renewed, and wrong sort of trees being harvested....neither do the powerstations have adequate carbon capture....

[oddoneout]

Things have moved on in the world of woodburners fortunately, but it's more than a little ironic that in recent years opening up fireplaces to burn wood in the most inefficient way has become so popular, even(or in some cases especially) in areas where legislation makes it illegal. As with so many things ignorance is at the root of many of the problems associated with wood burning. Salt-laden driftwood, and branches foraged from the local park are not good to burn whether on an open grate or in a state of the art double combustion stove; finding good quality logs takes time, effort and some appropriate knowledge.
At work we have a biomass boiler, installed a few years ago as an addition to the two existing oil fired boilers Grants were available and the council wanted to investigate the feasibility of such alternatives. 'Green' issues were the cover story, but the cost of heating oil had more than a little to do with it. The question of the origin of the wood pellets has been a source of criticism on site, compounded by the difficulties caused by council purchasing rules. The fuel purchased has to be the 'best deal'(ie cheapest). The fact that such 'best deals' often result in stuff the boiler and/or its feed system is not designed to run optimally on further muddies the 'green' credentials. There are UK sourced wood pellets for such boilers, but unless they met the price limit then they wouldn't even be considered. The fact that good quality pellets of the right sort would enable the boiler to run more efficiently and would reduce or eliminate expensive breakdown call-outs doesn't come into consideration - situation normal.
On the plus side it has reduced the oil demand(and cost) considerably, by providing sufficient heat for much of the spring and autumn period to enable one of the oil boilers to stay off much of the time. Whether a full environmental audit of oil versus biomass would show a net 'green' gain I don't know.
Several agricultural enterprises in this part of the world use straw based biomass boilers, making use of something which they produce in large quantities but don't otherwise normally have a need for.

[Dave2002]

Even back in the early 1970s, when I was working at the Centre for Overseas Pest Research, New Scientist ran an article warning of the carcinogenic properties of the smoke produced ty wood-burning stoves, advising that in urban areas these were best totally avoided. At that time, the principal problem was the relatively low temperature at which the wood burns in such stoves. Much higher temperatures, and thus lower generation of the carcinogens, were found in bonfires.

I think the modern wood burning stoves probably run at higher temperatures, and if fully enclosed present less of a problem regarding carcinogens. My experience of simple wood burning stoves in holiday cottages is that they tar up very easily, but I suppose the new pellet stoves are better than that. I just query the notion that these things can be carbon neutral, and be promoted by governments. My feeling is that in fairly small volumes (i.e. with small fuel demands) they might be, and if they can be fed with locally sourced wood which is forested carefully they might be neutral, but if they became popular - for whatever reason, the demand for wood pellets would cause totally unwanted effects, and would not justify claims of being "good for the environment:.

[eighthobstruction]

....I think you will find that the pellet burning really being talked about in these reports are very large gravity feeding biomass boilers used to heat large properties - warehouses - farm buildings - industrial buildings etc....the well off and entrepreneurial are in fact [generally] the only people who can afford to put in a boiler, feeding system, piping and infrastructure [it's not a cheap fix] BUT special offers /subsidies/clever accounting/EU subsidies etc etc make worth while over a longer time scale....except in the case in NIreland where the money rolled in imediately

[Dave2002]

There are some small scale domestic systems which have “benefitted” from the RHI. I hadn’t appreciated the scale of operations such as the Drax station. Seems dubious environmentally.