The Dew Drop Inn — Who’s Dropping in What in Biofuels?

by Jim Lane (Biofuels Digest) B20, B5, B100, E10, E22, E15, M50, E85, Bu12.5, HEFA 50. Is your head swimming with acronyms and blend ratios? Who exactly is making drop-in fuels, and what does that mean?

In the world of alternative fuels and transport, there are two types of technologies that are highly controversial:

1. Specifically to biofuels, fuels made (exclusively) from feedstocks that are also used for food production.

2. In every alt transport sector, infrastructure-incompatible fuels or engine technologies.

...Meanwhile, in the US producers have reached the distribution wall imposed by E10 blend limits; E15 blending is early-stage and controversial; for higher blends, there’s an acute shortage of pumps, and E85 prices aren’t tempting many customers.

But the controversy over infrastructure extends well beyond ethanol. Biodiesel producers have worked hard to move accepted blend ratios beyond B5 towards B20 and eventually B100.

These are, by definition, infrastructure-compatible fuels — although, as we shall see, fuels form a spectrum and there really isn’t a simple “wall” dividing incompatible fuels and drop-ins.

Generally around the world, fuels are blended by refiners – who add anything from oxygenates to detergents — and for the foreseeable future, expect to live in a world of blends.

These are feedstocks that can “drop into” existing refining capacity and can be used to make infrastructure-compatible fuels. ...These also can include renewable oils which can be “dropped into” a hydrotreating unit to make HEFA jet fuels, which are now certified for use in commercial aviation at 50/50 blends with conventional jet fuels. ...

These are, for example, renewable sugars that can be dropped in to fermentation systems and used to make, for example, cellulosic sugars at an old corn ethanol plant; or, synthetic biology technologies of the LS9, Amyris or Solazyme type can use them to make a range of tailored drop-in fuels and chemicals including diesel and jet. Catalytic technologies of the Virent type can also convert them into renewable diesel or jet — as well as chemicals. ...

Companies like Diamond Green Diesel, Dynamic Fuels and Neste Oil have built or are constructing, in biofuels terms, large-scale refineries to convert biobased oils to diesel fuel via hydrotreating. These can be blended by refiners or used as a 100% drop-in replacement. And, these providers can also produce renewable jet fuel at their plants.

... Coming along in the development pipeline, there is the technology developed by Chevron Lummus and ARA – that makes a 100% drop-in jet fuel from renewable feedstocks. There has also been research in making jet fuel from biobased terpenes...

Companies like Butamax, Gevo, Cobalt and Green Biologics are developing biobased isobutanol(Butamax, Gevo) and n-butanol (Green Biologics, Cobalt).

Isobutanol is case in point when we talk about “drop-in” being a spectrum rather than a spec. It is fully compatible with fuel infrastructure – e,g, tanks and pipelines and vehicle tanks and fuel lines. In terms of engine performance, it blends in at up to 60 percent with no loss in performance. However, EPA rules on emissions limit biobutanol right now to 16 percent blends (as a maximum – DuPont earned a waiver some time ago at that level) or 12.5 percent (generally). ...

A lot of people regard biodiesel as a drop-in fuel — and its true, there are vehicles out there running on B100 today. Generally, though, B20 is the maximum blend for which carmakers will not void a warranty, today, and a lot of vehicle models are still only approved for B5. That’s changing – slowly.

At the same time, biodiesel has come infrastructure incompatibility when it comes to pipelines — it can’t be mixed, not one drop, with jet fuel.

Now, there are E100 cars in Brazil, and there are ethanol pipelines there, too. So, for that reason, sometimes you hear about ethanol being described as a drop-in fuel. Which is to say, it drops-in to some cars and infrastructure, but far from all.

In the US, ethanol is not compatible with pipelines, and requires its own special tanks and equipment because it corrodes conventional fuel storage.

...In the chart below, we look at the 50 Hottest Companies in Bioenergy to see exactly who is making what, and what progress they have made towards commercial-scale.

...Of the remaining 36, 18 make ethanol, 3 make biobutanol, 3 make biodiesel, and 13 make high-blend or 100% drop-in replacements. (Doesn’t add up to 36? LS9 makes bnth biodiesel and drop-in surfactant alcohols, plus diesel and jet fuel).

Of the 13, eight have completed scale-up demonstrations of the technology and are developing first commercial projects, one is constructing a first commercial facility, two have completed small commercial plants and two are operating (Neste and Dynamic Fuels) full-scale commercial biorefineries. READ MORE