Regardless that man has burned wood and other organic materials for millennia to generate heat (and still do, using Agas and Wood-burning stoves with back-boilers), “BIOMASS” is a new phrase relating to burning non-fossil organic compounds to generate heat locally for a building, or industrially, to turn water into steam to drive a generator and generate electricity.

Biomass boilers typically burn wood or wood pellets. Their exhaust emissions are less harmful than fossil fuels and are therefore generally “cleaner” to manage as well as in terms of environmental impact. Biomass is not carbon neutral as there is a carbon expenditure in cultivating and processing the wood; transportation and combustion.

Biomass boiler schematic (Wood pellet-type)

Operating Efficiencies:

Wood chips are the cheapest form of heating available at 2.9p per kWh and wood pellets are approximately 4.2p. These prices are currently an illusion, based on microscopic demand for a plentiful supply. Current and planned forrestry levels, certainly in the UK cannot support a mass rollout of biomass boilers, based on the present technology. Wood chip and pellet prices, should mass rollout become the case, will rise with demand. The counter-argument at present is that the pragmatic issues with installing and maintaining a biomass boiler (see below) are likely to ensure demand remains low and that fuel prices, consequently, will also remain low.

Downstream from the boiler all existing system inefficiencies from the old heating system will also obtain with a new biomass boiler, e.g.:

  • Heat loss from pipework;
  • Difficult to zone – the whole system has to switch on to heat just one room;
  • Radiators are wet convection-based panels, not “radiant” and therefore heat the air, not the fabric of the building. Biomass boilers must run longer than Herschel Far Infrared heating to produce an equivalent level of comfort. However the per kWh costs of wood chip fuel (2.9p) and wood pellet fuel (4.2p) will pay for this this level of inefficiency despite the lower radiant efficiency and longer running hours required per day from the convection-based system.

The practicalities of switching to Biomass:

Like heat pumps, it is the practicalities of switching to Biomass that really complicate the case for adopting it.

  • Although an existing fossil fuel boiler system can be replaced with a biomass boiler, biomass boilers are significantly larger than their gas or oil counterparts and due to their footprint and noise, really need to be in their own room separate from living accommodation (these are not like gas combi boilers that can fit in a corner of the kitchen);
  • You require approximately 6-7cubic metres storage space for the fuel near to the boiler that is under-cover and dry;
  • The fuel storage space must be accessible to the delivery lorry;
  • A new flue for the wood smoke will be required – the existing boiler flue cannot be used. An existing chimney can be used but must be lined to cope with the wood smoke and regularly cleaned. New flues may be subject to local planning requirements and biomass cannot be used in “smoke-free” zones;
  • Fuel has to be manually moved within the store to ensure enough wood is in the hopper ready for the next burn, and burnt ash needs to be discarded;
  • Suitable Biomass fuels are not yet widely available;
  • Because the Biomass system has moving parts and burners, regular maintenance is required to maintain the boiler at peak efficiency. If the boiler packs up, like any central system, you lose your heating and your hot water.

Biomass is therefore a niche system for individual houses outside smoke-free zones, with delivery and storage space near a reliable, sustainable biomass fuel supply and you need to dedicate time to manage the fuel and ash. Current biomass boilers are therefore really not a pragmatic option in the vast majority of dwellings, certainly in urban and multi-occupancy buildings. The low price of the fuel is attractive. Given how “niche” the overall solution is, it is possible the fuel price will remain low, because mass adoption with the present technology is unlikely. However this low demand will also maintain the boiler purchase and installation price at relatively high levels.

Costs and Incentives:

  • Biomass boilers intended to replace existing Fossil boilers are subject to a pay-back tariff according to the Renewable Heat Incentive of 12.2p per kWh for 7 years.
  • Typical life expectancy of a biomass boiler is 18 years, roughly double that of a fossil fuel boiler, but for all practical purposes still not within the 20 year “Golden Rule” of the Green Deal: i.e. you are still likely to have to replace your biomass boiler once within the loan period and the loan principle should therefore cover for this.
  • A biomass boiler costs from between 5,00 to 11,000 pounds, including installation and flue. Installation must be performed by an MCS accredited professional.
  • Payback time, of a biomass heater is between 5 – 9 years and will vary depending on the efficiency of the boiler itself; use, and how well insulated the house is. Additional savings may be made depending on what fuel the biomass is replacing (with replacement of gas giving the least cost saving).

If your dwelling fits the specific “niche” for Biomass and you do not mind the maintenance overhead of the fuel, it could be a very attractive low cost option over the long-term, especially with the RHI incentive.

Herschel Far Infrared Heating as an alternative to biomass boilers:

  • Despite Herschel’s higher radiant efficiency and lower running hours per day, both wood chip and pellet fuel costs per kWh make biomass cheaper to run for longer;
  • Herschel Far Infrared is completely hassle-free. There are no deliveries to organise and have someone in the house waiting for the deliveries to arrive. No fuel to shovel around and no ash to remove and scatter.
  • The purchase and installation price of Infrared heating panels for a whole house will be at the lower-end of the purchase and installation costs of a biomass boiler;
  • Payback time for an infrared system, relative to the systems it is replacing is between 3 – 5 years, relative to the payback period of biomass of 5 – 9 years;
  • No ongoing maintenance is required for Infrared heating panels. Maintenance requirements for immersion systems are rare and no worse than the existing system being replaced.
  • An Herschel Far Infrared system can be considered for many, many more types of houses, especially multi-occupancy buildings and will prove cheaper and quicker to purchase and install and will never need to be replaced. Biomass is simply not a practical consideration for the vast majority of domestic applications.

 

Publisher: Herschel Far Infrared