Active and Passive: Competing Voices in Biofuels Design

November 28, 2012 |

Biofuels technologies aim for passive design, active reactions as they aim to compete at world-scale.

Where is passive design making a difference – and where are activity rates changing outcomes?

Extraction, extraction, extraction – there’s the ultimate competitive foe. Generally, renewables compete in the short term against fossil fuel prices – but in the long-term, against fossil fuel extraction costs.

Even if a new process produces a renewable at less then, say, the equivalent of $100 oil — there remains the possibility that the advent of competition, at scale, will cause fossil fuel prices to fall.

As Susanne Retka Schill noted in Ethanol Producer: “agriculturally based investors, farmers and small town business people…invested in corn ethanol when the impetus was to find a use for the mountains of surplus corn, with the explicit goal of raising corn prices to improve the rural economy…They know the nature of commodities is price volatility and small surpluses creating tight or negative margins.”

That certainly is the thesis of a study released in May by economists at the University of Wisconsin and Iowa State University, finding that in 2011, ethanol reduced wholesale gasoline prices by $1.09 per gallon nationally. According to the research produced at the Center for Agricultural and Rural Development, ethanol reduced the average American household’s spending on gasoline by more than $1,200 last year, based on average gasoline consumption data.

When to go active, when to go passive

A leverage point in this battle between making renewables and extracting fossil fuels? Producing high activity and low activity in the right places and times. As passive as possible in the process, as active as possible in the reaction.

Enzymes and catalysts? There, we need high activity rates, and in recent years this has been the area where there have been the most breakthroughs – enzyme costs and loads have come down dramatically from companies like Novozymes, Dupont, and Dyadic. We have seen the impact that highly-active catalysts can have with companies like KiOR, which have transformed the possibilities of fast pyrolysis. Raising the activity rates in classic reactions like methanol-to-ethanol, as Enerkem has worked on – another example of focus on activity.

Plant growth? There, we want the highest activity rates possible too – with companies like Ceres, Chromatin, Agrisoma, and SG Biofuels working hard on genetics to improve yields.

Processing technology? There we need low activity rates – that is, the winners move as little material as possible, re-use and re-generate where possible, and try to reduce the amount of heat that a given system needs, or the work required to fraction or transform biomass.

Passive design

The importance of passive design and low activity rates has never been more important than in producing fuels via micro-organisms such as algae or cyanobacteria.

We see the struggle to achieve passive design in three of the most transformative biofuels companies that have attracted passionate fans in their journey towards commercial-scale: Algenol, Joule and Sapphire Energy.

All three use modified microorganisms – in the case of Joule and Algenol, they milk them, as it were – extracting target molecules such as ethanol or alkanes as they are secreted. In Sapphire’s case, they harvest, and extract lipids from inside the cell wall.

All three are experimenting with passive design concepts.

Homeowners know the problems of passive design well. Where are some of the highest ongoing energy costs in running a house? Heating and cooling water, water separation (think, clothes dryers), cooling air, and moving water around in swimming pools, pipes, and washers and dishwashers. Insulation materials, angles to the sun, and gravity are some of the tools.

Why are there not more passively-designed houses in, say, the US? The country, by and large, exists in a temperate zone. Passive design has more adherents in places with high energy costs or extreme weather – particularly, cold climates.

In the case of Joule and Algenol, they are working with low-cost plastic tubes, laid out passively on the ground, that contain the medium in which their microorganisms live and work – and capture ambient sunlight, are fed CO2 and nutrients, and have a natural oil/water or alcohol/water separation approach.

The problem of heat

What problem will they encounter? Likely, heat. How do you keep the water from getting too hot, and reducing the activity rate of the microorganism or killing them off altogether? So, as we hear about the progress towards scale at Joule and Algenol, we generally hear about experiments that work on reducing activity and cost (such as Joule moving from a pilot system that looked like a solar panel, to a scale-up system that uses tubes along the ground), while trying to manage the problem of passively managing heat. There have been reports of Algenol experimenting with vertical designs to help with heat distribution.

The gravity opportunity

Another element in passive design: gravity. Flooding a rice paddy? For thousands of years, farmers have been using gravity. As much as we talk about the importance of flat land in growing algae – it is really better to have slightly graded land, to help move the water.

Other signs of the trend toward passive

Passive design is abounding in other areas as well. Think of Syngenta’s Enogen technology, which grows alpha-amylase enzymes that break down corn starch into simple sugars inside the corn plant. Agrivida, in a similar vein, has its INzyme technology, which is based on engineering cell wall-degrading enzymes into plants, which accumulate in high concentrations during plant growth, are activated (i.e. through heat or a pH change) post-harvest through proprietary processing techniques to break down cellulose into simple, fermentable sugars.

More evidence of passive design? Well, consider corn/soy rotation, which provides a passive form of nitrogen replacement. Or, look at systems that attempt to utilize feedstocks that are aggregated for other purposes – using sugarcane bagasse for cellulosic ethanol, MSW, sequestered carbon monoxide, or sawmill or pulp & paper plant residues.

Or, look at companies that use low-heat processes, or low-cost separation technologies, or off-the-shelf parts instead of custom-made.

The bottom line

Parity cost is important. But parity today may not be parity tomorrow.

Technologies that have gone just about as far as they can go in optimizing their activity – well, they may struggle as other technologies reach scale and shift energy prices.

Technologies that have robust paths for continuous improvement in making their designs more passive, their molecules more active – those are technologies worth a long look for the long haul.

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