By Anne Peralta
An Exclusive EcoSeed Interview
Creating biocoal out of bio waste is a simple, viable way to utilize the advantages of coal without the disadvantages of emissions and pollutants.
Renewable energy developer Twenty20 is seeking investors for a promising project in its portfolio: the production of BioCoal through torrefaction.
Marlies Kort, Managing Partner at Twenty20, describes the project as a simple, viable way to utilize the advantages of coal without the disadvantages of emissions and pollutants.
Coal is considered a primary energy source, as it provides cheap, abundant and reliable power compared to other hydrocarbon sources with geopolitical implications like oil or natural gas. However, coal is among the inherently most polluting fuels in terms of carbon dioxide and gaseous emissions.
BioCoal offers a means to sidestep these disadvantages through carbon neutrality: the torrefaction process utilizes bio waste that otherwise would be left to rot or sustainable biomass and transforms them into BioCoal, a product imbued with the properties of natural coal. As the process itself emits very little to no emissions, this allows for a closed carbon cycle saving up to 85% in emissions on the total CO2 footprint.
"We have spoken to the project developers and are very impressed by the practicality of the process," said Marlies. "Despite the fact that fossil coal is one of the largest contributors to CO2 increase in the world, there are still new coal-fired power plants being built. As there is tremendous political and economic pressure to reduce CO2 emissions, having a replacement for fossil coal and becoming carbon neutral is a huge advantage."
The basic principle of torrefaction is not new, as African tribes created charcoal by burying burning wood and simply waiting for it to blacken. The torrefaction process works much the same way: biomass such as reed, straw, cane or wood is heated between 250 and 300^0C in the absence of oxygen. Water and volatiles are removed from the material as cellulose, hemicelluloses and lignin biopolymers partially decompose.
The end product is dry, solid, blackened, and is much more energy dense and resistant to water than the original material. Like coal, it is hydrophobic and stable with no issues of water or rot, and has the nearly the same energy properties as coal.
"Imagine the possibilities," said Marlies. "Leaves, corn husks, straw, cane are all possible materials. We can use what is called 'waste' and take energy out of that. We're not speaking of a new energy source, but simply replacing the use of fossil coal with a sustainable alternative."
Torrefaction also offers a way to increase the utility of biomass. At present, one approach to reducing emissions in coal-fired plants is through co-firing with biomass. However, such a process requires both adjustments to the firing process as well as a careful choice regarding the biomass used.
"The project developer pointed out that wood pellets behave differently from coal, in addition to the milling required," said Ms. Kort. "Coal is usually crushed and blown into the furnace for highest burn efficiency. When wood is crushed, the fibers are never as fine as coal dust, so investments have to be made to absorb the wood pellets. As BioCoal is a material almost like fossil coal, it can be crushed, blown as dust, doesn't pose any storage problems and in that sense is much easier to blend into the original stream."
Vattenfall, a large European utility has already successfully tested a 50/50 mix of fossil coal and BioCoal.
"We see the most interest from coal-fired power plants as there's a huge advantage," added Ms Kort, "Many actually mention in their outlooks that they're moving towards torrefied materials."
With all the advantages, why isn't the technology more widespread? "There are about 60 developers working on 8 different technologies in the arena right now, but most of them run into problems when they try to scale up to industrial scale and move into the 24/7 continuous process. There are all sorts of scaling problems, but the large scale is actually needed to make it financially viable." said Ms Kort. "They're the first ones capable of doing this on an industrial scale like 100,000 tons of BioCoal per month."
An then there is the torrefaction process itself: every material considered to be torrefied has its own unique properties, and needs precise amounts of heating to be properly turned into BioCoal.
"You can imagine that if the material is heated a little more, or is left in the process just a little longer, you get a different end result," said Ms Kort. "End the process too early, the water vapour escapes but nothing has really changed. For every potential feedstock, you have to figure out the best recipe for torrefying it. And in this aspect, the project developers we represent have a distinct edge."
The project developers represented by Twenty20 have developed torrefaction technology capable of using light materials overlooked by other torrefaction technologies. Recipes for various forms of possible feedstock based on moisture content have also been established and completely automated process control ensures constant quality.
Twenty20 is inviting inquiries from interested parties who wish to invest in the scaling-up of this currently running torrefaction operation.
"We're looking for additional funding," said Ms Kort. "The project developers already have different potential projects with different feedstock such as straw and reed that are extremely inexpensive. Biowaste streams are already in place in Brazil, Mexico and the United States. There's a huge offtake market, ready customers in the coal and steel industries, a very simple technology, with emissions next to nothing. It's a very sustainable way to reduce emissions painlessly and profitably through replacement of a primary fuel source: coal."
Interested parties can contact Ms Marlies Kort at email@example.com for an investment brief. Learn more about Twenty20 and their services at http://www.twenty20.co.nl/.