Unit of Functional BionanomaterialsSchool of Biosciences

Prof Lynne E Macaskie Rafael Orozco Dr Mark D Redwood

Unique combination of advantages:◦ Renewable/sustainable energy sources

Organic matter and sunlight◦ Inherently free of fuel cell poisons

CO, H2S

◦ Waste disposal food waste agricultural residues

◦ Simple/cheap process Ambient temperature & pressure

MethodNet energy / areakWh/day/hectare

Source

UoB’s bio hydrogen

670 (UK) (+ gate fees)Biowaste2energy

Photovoltaics (PV) 665 (Bavaria) Bavaria Solarpark

Wind 480 (UK, on shore) MacKay (2009)

Anaerobic Digestion (AD)

425 (+ gate fees)Vagron, Netherlands*

Plant-derived bio-fuels

~120 (UK) MacKay (2009)

Algae-derived bio-diesel

Purportedly better than plants

* Including parasitic energy and total site area. Published values use the raw energy generated and only the space occupied by the digester.

DarkFermentation

Photo-Fermentation

Sugary waste

H2

Organicacids

Clean water

We focus on 2 methods1.Dark fermentation2.Photofermentation

Recycle excess bacterial cells

for metal recovery and

catalysis

Bench scale (1ml-20L) Pilot scale (120 L)

Ideally:1 Glucose 2 H2 + 1 acetate + 1 ethanol + 2 CO2

We select E. coli because◦ Fast aerobic growth◦ Tolerance to O2 during anaerobic fermentation

◦ Best tolerance to H2 partial pressure◦ No sporulation◦ Best-characterised genetic background for GM

E.g. removal of uptake hydrogenases

AnionCation

Anion-selectivemembrane

Electrodialysis uses an anion selective membrane and direct current

OAs cross the membrane due to negative charge

FermentationConcentratedorganicacids

- +

+/-

Organic acids H2 + CO2

Purple non-sulphur bacteria◦ Rhodobacter spp.

Anoxygenic photosynthesis

High yield, broad substrate range◦ e.g. Lactate 6 H2◦ e.g. Butyrate 10 H2

H2 produced by Nitrogenase enzyme◦ Very sensitive to NH4

+

◦ Select wastes with high C/N

Light conversion efficiency◦ Up to ~5%

Logging equipment for light intensity and temperature.

March, June and even October

Water heater pumps 30 °C water to the jackets

Tubular array Simulates 0.5 m2 of

sunlit area Variable volume

◦ up to 50 L Lamps deliver

programmed light patterns

Simulates any location or season

Spin-out company: Biowaste2energy Ltd◦ Formed in 2008◦ Startup investment from Modern Waste◦ Purpose: to commercialise waste to hydrogen

Business model◦ Gate fees for disposal of biodegradable waste

Biodegradable waste restricted from landfill

◦ Generate electricity from H2 ◦ Renewables Obligation Certificate.

Route to market◦ Add-on to anaerobic digestion

www.bw2e.com

13

How much hydrogen energy could be regained?◦ UK [food industry + domestic] = 24

M tpa◦ Potential to produce 280 M kg of

bio-H2

◦ Energy value: 5.6 TWh (terawatthour) and heat

◦ UK’s electricity usage: ~350 TWh pa

~2% of UK’s total electricity demand◦ Not including agricultural and non-

food industry wastes

Mol of

H2 e

quiv

ale

nt 1.5

1

0.5

2