Where are we with algae biofuels? PART II

October 14, 2014 |

NAABB-close-out-report-synopsisThe state of R&D so far. 4 NAABB advances brought the cost of algae biocrude oil down to $7.50 per gallon. 

3 roadblocks remain between today’s cost and $3.00.

This is a two-part series. In Part I here, we look first at the breakthroughs that have radically changed the costs and outlook. In Part II today, we look at where the opportunities lie to reach $2.00 per gallon algae biocrude oil.

PART II

The CLAW opportunity

While the NAABB consortium brough down the modeled cost of algae biocrude oil at scale to $7.50 per gallon, the Department of Energy has a target of $3 per gallons of “gasoline-equivalent fuel” for advanced algal biofuels by 2030.

naabb-4

How’s the gap going to be closed?

NREL, in a 2012 scenario tracing the pathway from $9.28 per gallon to $2.27 per gallon biofuels, identified:

1. Increasing the growth rate from 25 grams per square meter per day to 30 grams.
2. Increasing lipid content from 25% to 50%
3. Cutting harvest cost by 50%
4. Cut extraction cost by 50%
5. Sell Lipid Extracted Algae residual biomass for $500 per ton.

Of these, the easiest targets, after the NAABB work, will be in productivity, assuming that crop protection develops. As NAABB principal investigator José Olivares told the Digest: “A genetically modified strain of Chlamydomonas reinhardtii…provided 3x the productivity of the wild type. That modification is being placed into a production strain of Chlorella sorokiniana. The maximum productivity of the Chlorella wild type strain was around 16 g/m2/d. The productivity was modeled depending on season from 50%-200% increase.”

Perhaps the toughest target will be the $500 in co-product value, as “NAABB valued LEA as a feed supplement for animals at $160/ton and for mariculture at $200/ton. Whole algae for mariculture was valued at closer to $400/ton.”

In its close-out report, NAABB identified “the following broad research areas are important to the sustainability of algal biofuels…in need of further evaluation:

• Reduction of water in the entire production system;
• Robust cultivation, harvesting, and extraction systems;
• Improved production strains;
• Cost-effective sourcing of CO2, water, and nutrients; and
• Improvements in industrial design and logistics.

We’ll bring down NAABB’s targets to four key factors, we’ve summarized as CLAW

CO2 cost
Liner cost for ponds
Ash content
Water cost and usage

Summarizing the opportunities for further research, principal investigator José Olivares told the Digest that “The $7.50 /gal crude has some very significant technology changes in biology, cultivation, harvesting and conversion. What we saw as some of the biggest contributors were the cost of water, liners, and CO2. These are major operational and capital costs that need to be tackled very heavily.”

The DOE undertook two additional tasks in a new funding opportunity issued this summer, with a $25M funding opportunity with an interim goal of reducing the cost of algal biofuels to less than $5 per gasoline gallon equivalent (gge) by 2019. DOE outlined: “The funding will support projects in two topic areas:

Co-product revenue. Topic Area 1 awards (anticipated at 1–3 selections) will range from $5–10 million and focus on the development of algae cultures that, in addition to biofuels, produce valuable bioproducts that increase the overall value of the biomass.

Productivity. Topic Area 2 awards (anticipated at 3–7 selections) will range from $0.5–1 million and will focus on the development of crop protection or carbon dioxide utilization technologies to boost biomass productivity in ways that lead to higher yields of algae.”

So, let’s look at those seven, starting with the DOE’s targets:

The DOE’s FOA: From $7.50 to $5.00 per gallon by 2019

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Co-products. DOE writes: “Multi-disciplinary consortia will develop and improve yields of high-impact bioproducts and biofuels. A critical component of this topic area is that bioproducts are expected to increase the overall value of the algal biomass and still allow for biofuel production. Examples of research routes that could help meet this objective include but are not limited to: Co-production of specific molecules with downstream applications as petro-chemical replacements; Redirection of carbon flux to a metabolic pathway that results in synthesis of a valuable chemical; Improving a strain to make a valuable protein.”

Crop protection. DOE writes: “Novel, safe, and effective strategies need to be developed to control culture contamination events that result in diminished target feedstock yield(s). Additionally, integrated pest management systems need to be developed to control pathogens and herbivores. Examples of research that would contribute to crop protection include but are not limited to: Rapid detection systems to enable preventative treatments to ponds; Biological systems and/or engineering to increase resilience of culture; Novel chemical treatment protocols that are scalable, environmentally acceptable, and economically feasible.”

CO2 utilization. DOE writes: “Algae utilize a diversity of carbon concentrating mechanisms to maintain adequate carbon stores for photosynthesis. Obtaining adequate carbon is affected by the transfer of dissolved inorganic carbon into the cultivation system, levels of biologically available carbon, and sequestration of carbon by algae. Target improvements may be measured through enhanced photosynthetic efficiency, increased carbon efficiency, and improved rates of transfer, either into carbon reservoir, or uptake by algae from the reservoir. Improvements must result in improved productivity that could lead to higher feedstock yields. Examples of research that could help meet this objective include, but are not limited to: Mechanical engineering solutions for mixing and gas exchange; Alternative/Advanced CO2 or C supply-system development; Improved carbon uptake through strain engineering.

The CLAW areas: From $5.00 to $3.00 per gallon

The four remaining topics are, for now, not in the DOE’s set of targets for reducing costs to $5.00, but would be critical in reducing costs to $3.00 per gallon of gasoline equivalent.

CO2 cost

In their 2012 NREL survey, Ryan Davis and Andy Aden projected CO2 costs at between $36 and $70 per ton — that includes the merchant costs plus any conditioning. Free CO2 – well, it isn’t exactly free, because in the free or “cheap” scenario, CO2 conditioning will have to be done by the project owner.

One of the biggest factors is in the policy front. If CO2 recycling is included as a CO2 mitigation strategy by states (and OKd by EPA) for the purpose of greenhouse gas emission regulation, supply will blossom and cost can be expected to fall.

But there are other ways to source CO2. One of the most interesting is to partner with a CO2 emitter for feedstock, possibly capital, possibly land. That’s the case with Pond Biofuels and the St, Mary’s cement plant in Ontario, or BioProcessAlgae and Green Plains, in Iowa. In that case, the CO2 is monetized against interest in the venture — which is to say, it isn’t required to be paid for as part of the operating costs, but rather is reflected on the balance sheet as a contribution in kind to equity — or simply a factor in the issuance of shares. So, it’s dilutive to other non-feedstock investors, but does not cost the project.

Takeaway: Using Davis and Aden’s sensitivity projection, it could represent up to $0.66 per gallon of triglyceride oil, in terms of cost savings for the project.

Liner cost for ponds.

Overall, liners are expected to add as much as $2 per gallon of triglyceride oils, according to Sun, Davis et al. As Michael Bowowitzka and Navid Moheimani observed in their book “Algae for Biofuels and Energy”:

The pond liner is the single most expensive component of the construction costs of the ponds and cheaper alternatives have been explored. For example, various spray applied membranes have been tried in the past. These have included systems using mixtures of asphalt, rubber and other elastomeric materials, both with and without reinforcing plastics. However, these have as yet not proven to be as durable and effective.”

They caution:

“Unlined ponds have proven to be not suitable for the production of algal biomass for biofuels. Flow rates, light penetration and long-term stability are cited as factors.

For now, ponds have been lined in NAABB research, though Sapphire Energy has been flirting with unlined ponds.

Sapphire

NREL’s Ryan Davis and Mary Biddy, with PNNL’s Susanne Jones, wrote in 2013:

The installed price for pond liners is expected to make overall economics considerably more challenging. To ultimately achieve economic viability, proper site location and system design will be important to optimize such that a need for plastic pond liners is greatly reduced or eliminated, thus mitigating this cost bottleneck. Both the pond and liner costs are two of the most critical cost elements of the ALU pathway, given the very large surface area assumed in the present models of 10,000 acres of total pond area.

Perhaps the most important area of R&D is in the application of low-cost liquid streams that replaced plastic liners.

Takeaway: new lower-cost materials are likely to be required — a target for waste residues.

Ash content

Ashes to ashes, dust to dust, as the saying goes. Which is to say, when algae guys talk about “ash”, you should think “dust”, because that’s primarily what is driving up the “ash” content of harvested solids out of algae ponds.

Sapphire-construction

As NAABB principal investigator José Olivares remarked to the Digest:

“The report looked at real data that came from open ponds (for the most part) in the SW region. If this is the section that you are referring to, the ash content varied severely, sometimes this was due to just the natural ingredients left over from the nutrients and make up of the algae, but often our highest ash content was associated with blown in and settled dust/sand, residual salt from the saline waters, etc. It is a real world issue. Even Sapphire provided a similar observation and challenge.”

It’s an epic challenge — as NAABB noted, organic matter in their R&D ranged between 40-76 percent, post harvest. That’s a huge upside opportunity — as clearly, it costs to harvest and process all that dust-affected or dust-adjacent algae.

Again from Michael Bowowitzka and Navid Moheimani in their book “Algae for Biofuels and Energy“:

“It is also possible to cover the ponds, usually with clear plastic. Covered ponds are warmer and this may benefit productivity in cooler locations., however in high light locations covered ponds can reach very high temperatures greatly limiting the choice of species; covering the pons also reduces the effects of wind-blown dust and other contaminants.

The issue is cost and friendliness of neighbors, since dust is generally coming from down the street. There are products available to limit dust. For example, Cargill’s “Dust-off” dust suppressant has been used by miners, loggers, farmers, and municipalities for over 25 years to cost effectively control dust and maintain road surfaces.

For air-borne dust, some algae developers are turning to semi-open systems with tent like covers — but the costs are expected to be prohibitive for biofuels.

An interesting alternative that’s being explored is a mixture of glycerine and water. Remember, glycerine is a byproduct from biodiesel production using virgin oils — so, here’s an opportunity to make some biodiesel from algae oil, and use the low-cost, non-industrial grade glycerine mixed with water to suppress dust. The Journal of Environmental Protection has more, here.

In the end, prevention is tough and costly, whether at the origination end or a defending membrane protecting the pond. What may emerge are technologies that, if effect, aggregate dust in a manner not entirely dissimilar to aggregating algae. Dust flocculates — after all, that’s what comets, planets and stars are starting out with: cosmic dust. It may not be a case of keeping it out of the pond, but rather rendering it harmless to the pond by getting dust to the bottom of the water as quickly as possible. Happily, dust usually sinks.

Takeaway: Get the dust to the bottom, and out of the light.

Water cost and usage

Though water doesn’t cost much per gallon, it adds up. Recycling is your friend, evaporation your enemy, Yet, Davis and Aden report that it is not so much the water but what’s in the water that counts. We mentioned suspended dust — but even more powerful is the value of suspended nutrients in the water or in the algae biomass. Think NPK as any farmer does — nitrogen, phosphorus and potassium.

Sapphire Energy Hot 50_4

 

Takeaway: In their 2012 review, Davis and Aden found that 100% nutrient recycle could impact the cost of algae triglyceride oils by more than $2 per gallon, compared to 0% recycle.

The Bottom Line

Think like a farmer. Crop protection, input frugality, and field prep cost are huge factors. Just as with any farm. The threats tend to be microscopic — dust so small it suspends in water and blocks light, and two-celled predators that snack on algae. But they also tend to be about recycling residue — nutrients, CO2, water, even waste materials for pond liner inputs.

Make do with less. That’s the focus, that’s the road to $3.00 biofuels. And a lot of it is less about the lab and more about the field. The last mile might literally be in the last mile — the mile of ponds that form a modern algae farm.

In concluding its report, NAABB observed:

“We envision algal biofuels to be a viable competitor in the liquid transportation fuels market after a few more key improvements. A successful algal production farm requires a new approach to construction and cultivation that drastically reduces the cost of construction and its effect on capital layout. Furthermore, the algal farms must implement algae strains and cultivation methods that maximize biomass productivity year-round, such as the NAABB strain and cultivation technologies defined above. Finally, the use of major resources, such as key nutrients and water, need to be minimized and efficiently utilized. Combining technologies and systems in these three areas into a model integrated production and biorefinery system will bring viable algae-based biofuels into the market.”

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