AD Network Research Colloquium

Harvesting our roadsides for Low input High Diversity (LIHD) biomass

Dr Nick Cheffins

M.D Peakhill Asociates Ltd

Nick.cheffins@peakhill-associates.co.uk

LINCOLNSHIRE ROAD VERGE BIOMASS PROJECT

Project background• In Lincolnshire there are approximately 8,750 km (5,500 miles) of

highway of which 6,173 km are termed ‘rural’ and largely bounded by grass verges

Typical Lincolnshire ‘Drove’ verges

Project drivers

Economic• Local authority budget reviews to reduce the

management of the highways ‘soft landscape’ especially road verge will reduce the current flail and leave programme to one per annum on junctions and none elsewhere

• Could LIHD biomass work as a feedstock for s Anaerobic Digestion?

• Could its uptake reduce the land use for energy rather than food crops.

• Lincolnshire has one of the highest densities of farm based AD operators in the UK

Environmental & policy• Work by Lincolnshire Wildlife Trust and study

sites across Europe (PROGRASS / COMBINE)have confirmed the biodiversity gains from actively harvesting LIHD biomass

• Initiatives such as the National Pollinator Strategy are producing a supportive environment for LIHD Biomass related projects

• Improve the public perception of AD as bringing wider environmental benefits

Harvesting possibilities – preliminary demonstration August 2015

French Noremat engineered, tractor mounted 1.6m head front fixed & tractor with side mounted extendible arm 1.1m head cut and collect systems with detachable trailers

The 2016 Lincolnshire verge harvesting project – May 2016• Consortium project led by

Peakhill Associates Ltd

• Partnership• Lincolnshire County Council

• Lincolnshire Wildlife Trust

• Leeds University

• Gramagen Ltd (London Business School spin out)

• Scrivelsby Biomass Ltd

The 2016 Lincolnshire verge harvesting project – May 2016• Self propelled harvester on trial • Harvester unloading

Storage and use of verge biomass samples

• Samples from each harvest site stored in high density bales – May 23rd 2016 – 9 sample sites

Approximately 30 tonnes stored until bales opened 9th February 2017. Bales fed over one week -constituted approx. 20% of feedstock

Harvesting results

Region Site Harvest

Mowing

Strip No. Fwt/km Harvest Fwt/km Comments on August samples- NC

Wolds S1 H1 1 1.547 H2 0.9 Grass dminated verge for first breedWolds S1 H1 2 3.079 H2 1.2 Wider spectrum of plants in second breed

Wolds S2 H1 1 1.505 H2 0.8 Fine grass dominated

Wolds S6 H1 1 1.186 H2 0.7Plot located on the only regularly salted road included in

the trial - Thinnest and shortest (possible salt effect?)Fens S9 H1 1 1.604 H2 X 1.5 m breed mowed by third party prior to second visit

Fens S9 H1 2 2.205 H2 X 1.5 m breed mowed by third party prior to second visitFens S10 H1 1 1.071 H2 X 1.5 m breed mowed by third party prior to second visitFens S10 H1 2 1.942 H2 X 1.5 m breed mowed by third party prior to second visit

Fens S11 H1 1 3.09 H2 1.2 Coarse vigorous regrowthAverage 1.67 0.9 Average total fwt over two cuts = 2.57 t fwt/kmSTDEVA 0.73 0.2 Equivalent yield / ha = 23.4 t fwt/ha

Harvest Fresh Weight (Fwt) data and summary comments / calculations

May 20-23 2016 August 2-3 2016

Harvest dates

Soluble Contaminant analyses

• PTE levels analysed for all nine sample sites by University of Leeds produced values below the threshold requirements within the EA’s PAS 100 / 110 across all the samples

• One exception for one element (Hg) on one of the nine H1 samples was retested by a UKAS accredited lab and also returned a value within the above standards

• PAH levels came within the PAS standards for all 16 PAH compound assessed individually and as a total PAH presence for all the sites

Physical contaminant analysis

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Number of items

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Incidence of retrieved litter by category

4=metal drinks cans, 6=paper and cardboard & 8=plastic food packaging

Approximately 50 – 70% of collected litter is found within 50m of a

junction

Scrivelsby Biomass Ltd

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The theoretical biomethane potential of Lincolnshire roadside grass samples; highlighted as green bars and current feedstocks used in AD; highlighted as black bars.

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S2/H1.1 Maize

The experimental biomethane potential of Lincolnshire roadside grass sample S2/H1.1 and maize sample.

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Co-Digestion Control Co-Digestion 10% VG Co-Digestion 30% VG

The experimental biomethane potential of co-digestion experiments. VG= verge grass.

Conclusions• The verge harvester as tested produced a good quality cut that

ensiled satisfactorily.

• The gas out put at Scrivelsby increased when the verge biomass was added as 30% of the feedstock input for one week.

• The laboratory performance of the biomass did not decline after ensiling (Limited sampling)

• The verge harvester design of the Herder was problematic for UK economics – the fixed body reduced productivity

• Optimising productivity requires the harvester to be kept in operation with detachable trailer system

• The likely radius of operation would be within 10km of an ADO

Biomass valuation – trend interaction

March April May June July Aug Sept Oct Nov

Monetary value / t feedstock to AD plant operator function of dry matter digestibility and content

Digestiblity = bio-methane yield / unit dry matter

Dry matter yield t / km

Next stage in Lincolnshire - 2018

• Machine capable of maximum forward working speed in excess of 6.0 km/hour

• Evaluate potential to incorporate frame steering to assist manoeuvrability

• Carrying Capacity of up to 10 t biomass (Likely volume – 20 m3)

• Evaluate potential for side extension system to maximise carrying capacity whilst minimising overall vehicle length

• Guidance on overall width, length and height dimensions to be provided by Local Highways Agency

• Emptying and possible compaction systems to be proposed

• Unit to be capable of road travelling speed of up to 68 k/hr

• Cyclone style suction linked to arm capable of reaching 3 m to the side of its mounting

• Wrap around configuration preferred

• Diver view of harvester head overriding consideration

• Height of arm lift to be controllable to prevent contact with overhead electricity cabling

• Flail mowing and rotary cutting systems to be proposed

• Cutting head minimum width 1.1m

• Evaluate implications for a collecting head of up to 2.0m width

• Interchangeable cutting head to be proposed

• Proposals could consider a fixed body or demountable trailer system

• Requirements for highways signage and speed indicator systems to be specified by Local Highways Agency (needed)

20

Herder Kontannier 1.1m flail head cut and collect – 280,000 euro

Noremat harvester 1.1m flail head cut and lift with hook lift trailer – 230,000 euro

The Mulag SB 500 (Unimog mounted)

• So how much LIHD biomass is out there?

Asset Length - km

Accessible length - km

Harvestable area – ha 1

Potential biomass yield – t FWT at 24 t / ha

A road 69 38a 141 336

B road 62 43b 161 384

Unclassified 508 355b 1331 3,192

Km of drains 431 345c 2072 4,968

Total 1,070 781 370 8,880

a = Assumes 50% of the length of A roads is accessible – taking account

of the urban area of Boston and hard road verges etc.

b = Assumes 70% accessible of the length of B and unclassified roads is

accessible as above

c = Assumes 80% accessibility to dyke banks and berms with 20% lost

around bridges etc

1 = Assumes 70% of the accessible verges will also allow access to a

second 1.1 m wide strip giving a total cut of 2.2m. This also assumes that

both sides of the accessible road length provides an equal length and

area of verge.

2 = Assume the greater width of dyke bank and berms allows all the

accessible lengths to be cut to a width of 3.3m This also assumes that

both sides of the accessible road length provides an equal amount of

verge.

Linear assets and biomass yield estimates in the 10 km radius circle surrounding Hubbert’s Bridge

What could be out there

• The Linear Infrastructure Network – LINet , representing national, regional and local owner/mangers of soft landscape linear infrastructure in public and private ownership

• LINet has estimated that, across the UK there is a soft landscape of: • 400,000km of road verges + 31,000 km of Network Rail and

energy networks is equivalent to the land area of Essex!

• https://www.tcpa.org.uk/pages/category/green-infrastructure-partnership

Implication for future management for biodiversity

Linear mosaic cutting and regrowth windows