G's Biogas Plant

Brief Report on G’s Biogas Plant/Mushroom Business and Greenhouse Facility at Littleport, Ely with Will Forbes.


Biogas Plant

Plant operating at 2.4MW but now looking to increase this to 2.8-3MW.

Producing 45-50,000 tonnes of maize feedstock. Not using Rye as this apparently bungs up the plant and the stirrers in the pot can't cope.

Not putting any additive on the maize at clamping. Visually could see no difference between their maize silage and ours at OGR. Question is additive necessary or just an added cost, excuse my ignorance.

Harvesting maize at between 29-36% DM - Ollie Neil is the contractor

Feedstock for plant is being bought in from Cambs Farms Growers which is a Company within G's, managed by Charles Shropshire.

Growing a lot of Pioneer and Limagrain type varieties all FAO 210-220.

Also feeding onions but have also been putting in chicken muck, maize corn (maize which wasn't harvested was combined in December for the grain) this apparently is rocket fuel, and potatoes.

All digestate is pasteurised, they have 3 x 7m3 pasteurisation pots on site which when in use can process 21m3 of liquid digestate per hour. Solid passes through a screw press just like OGR. The pasteurised liquid digestate after the process is like a thick gravy and they are recycling some of this back into the fermenters.

Plant producing 60,000 litres liquid and between 13-17t of solid every 24hours.

Liquid Digestate is stored in a storage pot but also in addition they have Alligator Bags which are sited within a bunded mound. Each bag can hold 6000m3 (G's have 2 = 12,000m3) but apparently you can now get  7-8000m3 bags.

These are supplied by Tramspread. Tramspread are also doing all the liquid digestate spreading for G's using an umbilical system.

Cost for the bladders, pumps and pipework was £136,000 with Civils £175,000. Comment made they are in the fens and so the civils was expensive as they had to deal with the water table issues.

Life expectancy 15 years.

Cost therefore 12,000m3 storage used twice a year = 24,000m3.

24,000m3 x 15 years = 360,000m3

Cost £175,000/360,000m3 = 0.48p/m3 storage

CHEAP STORAGE if my maths is right!!!

Could you use the side walls between clamp 3 and clamp 4 as a site and then fill the ends in?????

Hot Water is coming off the exhaust jackets at 80C and being sent off to the mushroom farm…..report to follow. This is being returned at 83 degrees.

Mushroom farm using 55,000Kw/year which is the equivalent of between £550-570k in heating oil.

Hot water off the engine exhaust which is 478 degree's C is being processed through 5 ORCAN ORC exchangers. These cost 480,000 Euro's total. Each one can process between 12-22KW every hour so approx. 100KW extra electricity being generated every hour.

Mushroom Farm

Cost £19 million to build at last count.

First phase of build there were 24 tunnels, now 48.

All mushrooms are exclusive to Tesco's.

Site is producing 21,000 tonnes of compost per year which is then be returned back to land for spreading.

Source for compost which is all pre inoculated comes from Belgium. This is a mix of 7/8th  (horse manure, straw and chicken manure) and 1/8th sticky peat which goes on the top of the beds to provide moisture to the growing crop. Mycelium is added predelivery.

From crop going in to first pick is 16 days. After first pick they reduce the oxygen levels in the tunnel and increase carbon dioxide and humidity. This tricks the mushrooms into sporing again which produces a second flush. By day 24  the tunnels are emptied, cleaned and restocked.

Each tunnel is producing 20tonnes of mushrooms and per week they are harvesting 8 tunnels.


Producing 135 million plant/year

4 people employed on site

There are 670,000 tray movements per year

There are 21 bays each 120metres long, on a 3ha site.

14 bays are cold and 7 heated to 16 degrees day and night for celery.

Greenhouse in use from November to August. (Spain produce their own plants hence not 12 months year round).

Producing plugs per tray ranging from 150/tray, 176/tray and in peak summer 215 per tray