John Walsh Determining the real value of on-farm Anaerobic Digestion Penderfynu gwir werth Treuliad Anaerobig (Anaerobic Digestion) ar y fferm

 Measure crop yield  Measure leachate levels  Above findings will provide the basic information to determine accurate economic values for AD, for government and farmer Aims and Objectives Nodau ac Amcanion

 Two soil types ◦ Conventional ◦ Organic  Grass and grass/clover mix established  5 treatments ◦ Control; NPK; N; Fresh slurry; Liquid digestate ◦ Normalised for N content (150 kg ha -1 ) ◦ Applied via surface spreading  5 reps, 70% field capacity  Managed for 15 weeks  Three harvests  Analysed for ◦ Yield (crop) ◦ Leachate: amount of N and P present (soil) ◦ Bacterial and fungal growth (soil) MethodsDulliau

 Crop Yield  Fresh slurry (FS) produced half the yield of liquid digestate (LD) in 3 out of 4 treatments  No difference in yield between LD and NPK in 3 out of 4 treatments  Leachate  LD and FS statistically the same level of leachate  NPK had more leachate than LD in all treatments ResultsCanlyniadau

Crop YieldCynnyrch Cnwd

 Digestate had double the yield of fresh cow slurry in 3 out of the 4 treatments  NPK cost £281/tonne  At a rate of 150 kg N /ha, digestate saved £103/ha on fertilizer expenditure  Simple valuation: introduction of AD doubles the value of a farmers organic fertilizer Fertiliser SavingArbed Gwrtaith

Mg/L NO 3 - Total NitrateCyfanswm Nitrad

Total AmmoniumCyfanswm Amoniwm

mg/L PO 4 Total PhosphateCyfanswm Ffosffad

 AD: 500 kW 11.5 (p/kWh)  AD: 500 kW 9.0 (p/kWh)  Wind: 15 kW – 100 kW 24.1 (p/kWh)  Wind: 100 kW – 500 kW 18.8 (p/kWh)  Wind: 500 kW – 1.5 MW 9.4 (p/kWh)  Current FITs price doesn’t reflect all benefits of AD  Positive externalities of AD have not been valued Feed-in TariffsTariffau I’w Cynnwys

 Doubles the value of fertilizer produced on farm.  FIT’s and ROC’s under priced for AD  Double advantage of reducing fossil fuel usage and cutting down on current GHG emissions  Only renewable energy source to do this  More nitrogen and phosphorus stays in the soil than inorganic fertilizers Conclusions: ADCasgliadau: AD

 My supervisors for guidance: Prysor Williams, Gareth Edwards-Jones, Davey Jones AcknowledgementsDiolchiadau