Syngenta biogas cropsHigh-energy varieties are the key to profitable production

Syngenta is one of the world’s leading companies with more than 26,000 employees in over 90 countries dedicated to our purpose: Bringing plant potential to life.

Anaerobic digestion

Anaerobic digestion (AD) is the process where biodegradable material is broken down in the absence of oxygen. The products of an anaerobic digester are biogas and digestate. Biogas is a mixture of methane and carbon dioxide (60:40) and is combustible so can provide heat, electricity or both. However, it can also be ‘cleaned’ and the pure methane used to power the mains gas grid or used as vehicle fuel.

Digestate is essentially the residue that cannot be digested and converted to gases. This is very high in plant nutrients like nitrogen and potassium and can be converted into useful by-products, like fertiliser. An anaerobic digester needs to be treated like a living creature and a balanced diet is the key to gaining the maximum output.

NK Baleric

NK Jasmic

8.0 10.0 12.0 14.0 16.0 18.0 20.0

200

180

160

140

120

100

80

Met

hane

Yie

ld (K

LN/h

a)

Energy yield (GJ/ha)

Energy yield = methane yield

Biomass Type

80

70

60

50

40

30

20

10

Met

hane

yie

ld (

KLN

/ha)

High-energy Type

rest of plantcob

Source: Joint Biogas Project: Bavarian Institute for Agriculture, Chamber of Agriculture, Lower Sacsony, Syngenta.

A ‘biomass type’ maize variety has a lower energy content but a higher volume yield. A ‘high-energy type’ maize variety has a higher energy content but a lower volume yield.

Although the total gas yield per hectare is arguably similar across the two types, with a ‘high-energy type’ there is much less material to harvest, transport, store and put through the digester for every megajoule of energy or cubic metre of biogas produced.

When selecting varieties for AD production, growers should take account of ME yield and general field characteristics, such as early vigour and standing power but also consider the demand on resources at harvest.

Depending on the feedstocks available, a 499 kw/h AD plant may require 100 – 200 hectares (250 – 500 acres) of maize. Larger plants, up to 2 mw/h, could need 750 – 1000 hectares (1800 – 2500 acres) of maize to ‘feed’ them. With such large areas to harvest, it is important that growers consider the maturity of the varieties to phase the harvest, while still achieving optimum yield and quality.

Syngenta’s maize breeding programme is focussed on producing varieties that deliver maximum ME yields, while retaining the key characteristics for reliable production in the UK climate. For example, the following varieties have been fully tested in UK official trials (National and Descriptive List):

MaizeThere is a direct correlation between the energy levels of the feedstock and the amount of methane produced. Maize is a favoured feedstock for biogas production specifically because of its significant and cost effective energy yields.

There is a theory that feeding sheer bulk from maize into the digester will create the highest methane output. However, subsequent independent research has counteracted this and has proved that maize varieties that have less bulk but a high metabolisable energy (ME) production and silage quality, are the best choice of feedstock for the digester.

Independent research has proved that maximum, profitable biogas yields come from ‘high-energy type’ maize varieties that mature to at least 28 - 32% dry matter.

Sugar beet

AimantaSugar beet

SY MuseSugar beet

Sentinel

Syngenta Seeds Ltd., CPC4, Capital Park, Fulbourn, Cambridge CB21 5XE Tel: 01223 883400 Fax: 01223 882238 Email: customer.services@syngenta.com Website: www.syngenta-crop.co.ukSyngenta AG June 2012. GQ 02955.

In addition to maize, sugar beet is an excellent substrate or co-substrate for the digester, due to its large and easily convertible biomass and high sugar content. The crop can produce exceptional energy yield and its composition allows for fast fermentation. It provides a significant boosting effect when used with other feedstocks.

Biogas production from Syngenta sugar beet varieties is especially good, due to their high yielding genetics, combined with the Syngenta low tare root shape and a lower risk of deposit formation in the digester.

Sugar beet

What the independent specialists say...We’ve seen from our trials in Holland that dry matter yield, sufficient dry matter percentage at harvest and silage quality are all important factors for biogas. Growers just choosing the highest-yielding variety may not be getting the best economic yields per hectare. If metabolisable energy yields or dry matter percentage is poor, methane yields are also likely to be low.

Following several years of specific biogas variety trials we can give clear advice to biogas farmers: for the most profitable biogas production grow varieties with high energy yields and good silage quality that reach at least 28 to 32% dry matter.Jos Groten

Head PPO (official) maize trials, Holland

“

“

Syngenta is a global agribusiness committed to sustainable agriculture through innovative research and technology. A snapshot of what we do:

• We invest more than $1bn each year in R&D

• 5,000 of our 26,000 employees are involved in research and development

• We have hundreds of collaborations with external research partners and universities

With products in seeds, seed care and crop protection, Syngenta helps growers around the world increase their productivity and address the world’s increasing demand for food, feedstock and FUEL.