Frequently asked questions
Frequently asked questions
How loud is a biochar pyrolysis unit?
The loudest working part of the system is the electrical generator. At a distance of three metres it's 65-70db. 10m from the door it drops to 50-53db. As a comparison, a restaurant or office is regularly around 60db and the maximum level of noise allowed in a working environment is 85db.
Whilst the plants will produce biochar through the night, activity at both sites will be during daytime only. Noise from site activity is unlikely to exceed that produced currently. If chipping of wood takes place, this may be noticeable but would be at low level and likely to be masked by existing road traffic noise. The sound levels from the site at nighttime with the doors closed at either plant will likely be negligible. For our proposed site in Ludlow, a full acoustic survey and impact assessment will be conducted prior to applying for planning consent, and any additional mitigation measures identified as required.
Will the process create odours?
There are no smells from the operation of a biochar plant as gases and oils are combusted internally and the emissions from this process are scrubbed before being dispersed via a flue. The proposed feedstock is woody material from felled and chipped timber and woody material rejected from composting operations because of it being too large, these materials should not cause any odour issues but we will monitor this. We are not planning to use any food waste in the process at any site.
Are there emissions from the unit?
At our site in Powys, our site operators Woodtek Engineering Ltd clean all the emission before venting to the atmosphere using a wet scrubber meaning that particulates are virtually eliminated.
- Methane: 0 emissions
- Sulphur and chlorine: 99% removal
- Nitric oxide and nitrogen dioxide: 95% removal
This would be the same for a unit at the proposed Ludlow site.
Both sites will also be subject to strict environmental permitting legislation that requires controls on emissions:
The environmental permit will require that all emissions are continuously monitored and meet the numerical Emission Limit Value (ELV) standards set out in the permit. These ELV’s are based on criteria set of incineration plants and are very strictly controlled.
Our Powys plant requires consistent feedstock to optimise gasification, and the emitted gases are carefully controlled to ensure optimal combustion with air. The whole process is computer controlled to ensure optimum combustion conditions are maintained.
Combusted gases are then subject to abatement using wet scrubbing to remove residual pollutants. The final discharge is measured continuously for key pollutants to ensure compliance. A full air quality impact assessment based on the highest permitted levels of pollutants will be conducted to ensure that any polluting potential is negligible. Actual emissions will be much lower than the maximum permitted.
Will there be a chimney and smoke at the proposed Ludlow site?
A 10 metre flue stack is proposed subject to dispersal modelling (10m from ground). This is shorter than the existing tanks on site. It will emit steam/vapour, after pollutants have been removed.
How big is a pyrolysis unit?
Pyrolysis units are housed indoors. The length of the unit in Powys is 9m; it is 2.5m wide, and 5m tall.
How much carbon will be removed through the pyrolysis to biochar process?
Our unit in Powys will be able to sequester (capute and store) the equivalent of 2,000 tonnes of CO2 from the atmosphere every year. As a comparison Shropshire Council’s net direct (scope 1 and 2) carbon emissions in 2023 were 2,539 tonnes of CO2e.
Our proposed unit in Ludlow will be able to store the same amount. The zero-carbon energy produced by both units will also help offset carbon emissions associated with electricity from the grid.
How long is the carbon stored?
When biochar is added to the soil it stores the carbon for 100+ years. In materials, storage time depends on how long the material is used for and if the material is reused or recycled.
Where can the units be placed?
Units can be placed on industrial or agricultural land, subject to the relevant planning permissions being granted.
Our first site near Welshpool is on agricultural land, near to an existing farm.
Our proposed site on Coder Road Business Park on the outskirts of Ludlow was the home of our former anaerobic digestion plant and is designated for light industrial use. The Coder Road site is already owned by us and the location, its buildings and former use lend very well to installing this technology.
What feedstock is used?
We're planning to mostly use mainly woody materials. Feedstock types include:
- Arboricultural arisings
- Virgin whole tree
- Virgin wood chip
- Parks and gardens arisings from our estate
- Possibly woody material rejected due to its size from composting operations
Will feedstock be pre-processed on site – if so how?
Processing may involve chipping, mixing and drying of feedstock. Depending on quantity and size of material, chipping may need to be done outside. All mixing of woody material is carried out inside the building. Feedstock will be stored inside wherever possible (to avoid moisture increase).Chipping outside will create a small amount of ‘woody’ odours local to the site, however these should not extend much beyond either site. Wood odours from chipping are neither strong nor offensive.
When will the plants operate?
Operation at the proposed Ludlow site will be 24/7 but delivery times between 7am and 6pm will be imposed at planning stage subject to approval.
Operation and deliveries to the Powys site will not differ much from the existing operations. Their pilot pyrolysis unit was operational for 4 years up until September 2024.
Will there be lots of additional vehicles?
During the development stage some vehicles will be required to bring plant, equipment and materials to the site but this is expected to be just a few per day. During the operational phase vehicles will be required to deliver feedstock for the process and remove the biochar product. We expect this to require two to four small lorry movements per day if small vehicles are used or one vehicle every other day if a large vehicle is used. The times permitted for deliveries and collections will be set by the planning process.
At the rural Welshpool site the number of vehicles may increase very slightly as the new C1000 unit is larger than their pilot C600 and so needs more feedstock.
What throughput will the biochar plant have?
The amount of material delivered to the site in a year will vary as it depends on the moisture content of the feedstock, if wet material is delivered it weighs more for the same volume and then needs to be dried for processing. We expect to treat 3,500 to 4,000 Tonnes of dried feedstock per year.The ‘wet’ weight of this material is likely to be around 5,000 Tonnes per year. This is similar to the scale of the operation of the former anaerobic digester.
The Welshpool site will be the same in terms of throughput, as the Ludlow site.
When could the Ludlow site be operational by?
Subject to planning permission being granted, the plant in Ludlow could be installed as early as summer 2025.
Register interest in renting a biochar kiln or stove
We have recently purchased some equipment which we intend to loan out to community groups, individuals, forest schools, etc. The equipment is designed to create relatively small amounts of charcoal / biochar that can be used to store carbon and improve compost.
We currently have:
- 3 Kon Tiki kilns. These are quite large and require a trailer to move them around.
- 7 Forest TAWI stoves. These are smaller stoves designed to be portable.