Illuminating algae Stripping the costs of algae production in PBRs
Dr Douglas McKenzie Xanthella Ltd Cambridge 2014
Academia to Business
XANTHELLA
Xanthella
Xanthella is developing innovative products and services aimed at accelerating the development and reducing the cost of producing algae as feedstocks for industrial products and as solutions to problems. Our customers are people and organisations who want to grow or use algae.
First products are the Pandora family of internally-lit, PBRs. This work was enabled through SMART Scotland and TSB awards to Xanthella. Currently commercialising Cyclops PBR and developing larger Pandora systems.
Algal solutions
Industry problems
Academia
Scale Cost Time
What’s the problem?
Climate
change
Cheap Oil has passed
Pricing instability
Fuel supply insecurity
Rising costs in
Agriculture and transport
Q: Where is the solution?
A: Renewable energy sources at
scale that are price comparable to
fossil fuels, carbon neutral and can
be delivered within this decade.
Hydro; wind, wave, tidal; biomass CHP
AD; fuel cells; solar PV; nuclear
Batteries; hydrogen; biofuels
Electricity Liquid Fuels
Requirements of 3rd generation
biofuels US military
Scale
No or modest impact on other industrial processes (particularly agriculture)
Cost equivalence with fossil fuels (including CAPEX)
Security of supply
Drop in fuel requiring little or no engine modification
High performance (at least equivalenct to fossil fuels)
Major commercial opportunity: also some prospects on green front
especially in civil aviation
the pain Algal feedstocks too expensive for commodity production which limits “real world” applications of algal products to high value products. Algal ponds are relatively cheap but have poor land use efficiencies and have major issues with productivity, contamination and harvesting. GMO No-No! Photobioreactors (PBRs) are much more efficient than ponds but are more expensive to build and operate PBRs offer scope for considerable improvements in cost effectiveness. No standardisation of design meaning market is open to innovative designs. Existing markets for PBRs outside of biofuel production
how to reduce the pain of cost
Capital costs: CAPEX; Operational costs: OPEX.
(CAPEX creates an asset; OPEX is immediate hit on profit and loss
1: Effects of scale on both CAPEX and OPEX
2: Architecture:
simple is good
3: Materials:
Inexpensive is good
Smart is good
4: Operational cost effectiveness:
Low feedstock cost
High efficiency in production
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effects of scale
Needs of algal biomass
350,000 litres of water for 1000 litre
of algal oil (pond): (10,000 – 100,000l PBR)
1.8 tonnes CO2 for 1 tonne of algal biomass
500 MWh of white light for 1000l AO
Depends on species and fate
of biomass
Large scale is……large!
500 MW coal fired power station produces
around 10,000 tonnes of CO2 per day
So needs to produce around 5,500 tonnes of
algae per day to completely sequester CO2
This requires 2,750,000 MWh of white light
(The coal plant produces 12,000 MWh per day
of electricity)
In Brittany solar insolation is 5kWh/m2 per day
in August
So would require ~300,000,000 m2 of light
gathering surface = 300 km2 (in August!)
Water requirement > 6 million litres per day
BUT: you would get a lot
of oil back: (assume
50% oil content) ~3,000
tonnes per day
(200,000,000 tonnes per
annum EU: so about
0.5%)
Appropriate Local Scale
Annadale will produce 225 tonnes of CO2 per annum
from fermentation and 625 tonnes) from heating.
Needs about 500 tonnes of algae to sequester
Produces around ~300,000 l of algal oil : which is
more than distillery uses in heating oil (225,000l)
Requires ~5 million litres of water The distillery will
produce 3.4 million litres of waste water so most met
from the waste waters. Some of the water can be
recycled so the process is not likely to require
additional water input.
The waste water will provide sufficient nutrients to
support the algal growth.
150,000 MWh of energy: 150,000 m2.
All requirements can be met at site
effects of scale
Scale increases CAPEX risk also OPEX risk
Tipping points where different technology is required for scale up and
feedstocks become limited increasing cost through acquisition of transport.
Large scale demands solar.
Modular can give you scale savings in manufacture lots of small units rather
than few very large units – OPEX savings possible as well easy to predict
behaviour and intervention easy. Easy to relocate and produce pseudo
continuous production by staggering production.
One size will not fit all so flexibility important in PBR design
“the times they are a changing”
Lessons from US fossil oil production
algal diversification Interest in algae as a source of drop-in biofuel has been responsible for an multi-billion dollar explosion in research and commercial activity globally into the production of algal biomass. Tight play technology has reduced strategic demand for biofuels. Algal biomass can be also be used as feedstock for a wide range of products including pharmaceuticals, nutraceuticals, research tools, pigments, plastics as well as biofuels. The existing markets for these products has been estimated at €4 billion per annum. Biofuel companies adapt to look at these markets as they cannot make money from biofuel production and investor sentiment changes. Scale requirements significantly less, making PBRs more competitive and powered light more desirable
Distributed production of algal biofuels by
electricity?
architecture
architecture
Light is key as it is the feedstock that is ultimately limiting in a production system. In many PBR designs the necessity to capture light imparts a large surface area to the PBR and thus cost. Volume of light capture PBR may be 30x higher than necessary. Light capture PBRs introduce problems of over heating; photo-inhibition in early stage cultures; over-engineered for low density culture stages. If light capture could be separated from light delivery in a cost effective manner then PBR architecture could use familiar, low cost vessels.
Principle of gas lift reactors
Gas sparger
Gas bubbles
Fluid flow
Fluid surface
Traditional gas
lift PBR
Lighting external to PBR; requires large surface area; problems with fouling of PBR internal surface and loss of energy transfer efficiency
Xanthella’s PBR
concept
Lighting internal to PBR: either from light guides or internal LEDs; only uplift tube lit;
high energy transfer efficiency; PBR can have small surface area. Uplift tube made from the
lighting and sparger elements (Goldilocks Component) Simplifies design considerably
and reduces costs. Temperature control via gas sparging
Mk 1 15 l and Cyclops PBRs
Zeus Light Controller
Flexible and waterproof LED light sheet
materials
Smart wall materials for solar reactor: Light processing to optimise photosynthesis Auto reflection to prevent overheating Gas exchange through wall Powered lighting LED efficiency increasing rapidly and costs falling Most cost effective solutions may be not be most efficient for photosynthesis Different wavelengths of light used to control algal and contaminant behaviour
sol
Lots of energy but energy density low; half of wavelengths wasted; problems of IR and UV). Requires high surface areas to capture light leading to poor surface to volume ratios (about 30X excess volume required)
Light processing and transmission
Problems of solar is relatively weak power to area ratio, angular momentum; wrong wavelengths
Newtonian optics too expensive and inefficient for concentration, transmission and processing. Non-linear methods can intercept light and change its momentum and wavelengths. Energy losses but 50% to play with. Would allow separation of light capture from light delivery thus reducing costs: Apollo Net concept. Recently successful in TSB competition: £200K project with St Andrews to develop light processing methods. Further TSB project with Strathclyde on using light to control contamination within PBRs.
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Conclusions
1: The feedstocks necessary for algal production are more likely to be
available locally when the output requirement is modest
2: While large scale plants may produce economies of scale over smaller
ones, these may be wiped out by the need to transport feedstocks onto the
plant site. Financial risk increases with scale
3: Smaller plants easier to physically accommodate and thus less likely to
be resisted from NIMBYism
4: Because of diverse requirements, modular PBRs may offer advantages
over larger scale bespoke PBR systems.
5: Light processing and transmission can offer significant advantages in
cost effectiveness through improved architecture
6: High value products make artificial light much more competitive and can
lead to further cost reductions in both CAPEX and OPEX
Thank You
www.xanthella.co.uk