Wood fuel
In contrast to civilizations in relatively arid regions (such as Mesopotamia and Egypt), the Greeks, Romans, Celts, Britons, and Gauls all had access to forests suitable for using as fuel.
Over the centuries there was a partial deforestation of climax forests and the evolution of the remainder to coppice with standards woodland as the primary source of wood fuel.
H. L. Edlin, in "Woodland Crafts in Britain", 1949 outlines the extraordinary techniques employed, and range of wood products that have been produced from these managed forests since pre-Roman times.
Masonry heaters or stoves went a step further by capturing much of the heat of the fire and exhaust in a large thermal mass, becoming much more efficient than a fireplace alone.
Metal stoves are often lined with refractory materials such as firebrick, since the hottest part of a woodburning fire will burn away steel over the course of several years' use.
Notable innovations from that era include the Ashley heater, a thermostatically controlled stove with an optional perforated steel enclosure that prevented accidental contact with hot surfaces.
The decade also saw a number of dual-fuel furnaces and boilers made, which utilized ductwork and piping to deliver heat throughout a house or other building.
The growth in popularity of wood heat also led to the development and marketing of a greater variety of equipment for cutting, splitting and processing firewood.
Consumer grade hydraulic log splitters were developed to be powered by electricity, gasoline, or PTO of farm tractors.
In 1987 the US Department of Agriculture published a method for producing kiln dried firewood, on the basis that better heat output and increased combustion efficiency can be achieved with logs containing lower moisture content.
[4] The magazine "Wood Burning Quarterly" was published for several years before changing its name to "Home Energy Digest" and, subsequently, disappearing.
The boilers are large enough to hold a fire all night and can burn larger pieces of wood, thus less cutting and splitting is required.
This is due to design characteristics such as the water-filled jacket surrounding the firebox, which acts to cool the fire and leads to incomplete combustion.
As a sustainable energy source, wood fuel also remains viable for generating electricity in areas with easy access to forest products and by-products.
As with any fire, burning wood fuel creates numerous by-products, some of which may be useful (heat and steam), and others that are undesirable, irritating or dangerous.
Smoke, containing water vapor, carbon dioxide and other chemicals and aerosol particulates, including caustic alkali fly ash, which can be an irritating (and potentially dangerous) by-product of partially burnt wood fuel.
A major component of wood smoke is fine particles that may account for a large portion of particulate air pollution in some regions.
Large quantities of smaller oxygenate species are released during the combustion process, as well as organics formed from the depolymerisation reaction of lignin such as phenolics, furans and furanones.
[13] The burning of fuel woods has been shown to release organic components over a range of volatilities, over effective saturation concentrations, C*, from 101-1011 μg m−3.
[citation needed] Depending on population density, topography, climatic conditions and combustion equipment used, wood heating may substantially contribute to air pollution, particularly particulates.
[citation needed] Particulate air pollution can contribute to human health problems and increased hospital admissions for asthma & heart diseases.
However, in many countries, for example in Europe and Canada, the forest residues are being collected and turned into useful wood fuels with minimal impact on the environment.
The shortage of suitable firewood in some places has seen local populations damaging huge tracts of bush possibly leading to further desertification.
[17] In an attempt to provide quantitative information about the relative output of CO2 to produce electricity or domestic heating, the United Kingdom Department of Energy and Climate Change (DECC) has published a comprehensive model comparing the burning of wood (wood chip) and other fuels, based on 33 scenarios.
Scenario 33 for example, which concerns the production of heat from wood chips produced from UK small roundwood produced from bringing neglected broadleaf forests back into production, shows that burning oil releases 377 kg (831 lb) of CO2 while burning woodchips releases 1,501 kg (3,309 lb) of CO2 per MWh of delivered energy.
However, in scenario 32 of that same reference, which concerns the production of heat from wood chips that would otherwise be made into particleboard, showed that only 239 kg (527 lb) of CO2 per MWh was released.
For example, the city of Montréal, Québec passed a resolution to ban wood fireplace installation in new construction.
On March 7, 2018, the United States House of Representatives passed a bill that would delay for three years the implementation of more stringent emission standards for new residential wood heaters.
In Finland, there is a growing interest in using wood waste as fuel for home and industrial heating, in the form of compacted pellets.
[28] The UK is the single largest consuming market for industrial wood pellets, in large part due to its major biomass-fueled power stations such as Drax, MGT and Lynemouth.
