Is the time right for underground coal gasification?

BLUEFUELENERGY.COM: Coal is the most abundant fossil fuel on the planet. Given the human population’s insatiable appetite for energy, it is unlikely that this resource will go untapped. Therefore, the challenge is to develop methods that allow coal to be exploited in as environmentally sensitive a way as possible, so that we may reap the economic rewards of the energy it holds without compromising the livability of the planet.

One of the conventional methods of producing DME is through the gasification of mined coal to produce syngas which is then synthesized into DME. This process can be costly and environmentally damaging. The underground gasification of coal (UGC) may offer some answers to these disadvantages.

The UCG Partnership has outlined the basic concept behind UCG and a number of financial and environmental advantages of UCG relative to conventional mining and subsequent gasification techniques.

“Underground Coal Gasification is the gasification of coal in situ, directly in the underground seam, producing a high quality, affordable synthetic gas that can be processed to provide fuels for power generation, diesel fuels, jet fuels, hydrogen, fertilisers and chemical feedstocks. The technique offers many financial and social benefits over traditional extraction methods, most notably lower emissions, as no coal is brought to the surface and the gas can be processed to remove its CO2 content.

Many countries rich in coal reserves have few alternative indigenous energy sources, however nearly 85% of known coal reserves are deemed unmineable with surface mining techniques… Experts believe UCG could triple or quadruple the availability of coal globally.

Financial Benefits
• Capital and operating costs are lower than in traditional mining
• Reduced cost of plant installation - No Surface Gasifier
• Syngas can be piped directly to the end-user, reducing the need for rail / road infrastructure
• Lowers the cost of environmental clean up due to solid waste being confined underground
• CCGT power plants can be switched from natural gas to cheaper UCG product gas
• Manufacture of chemicals such as ammonia and fertilizers
• Synthesis of liquid fuels at a predicted cost equivalent to US$20/barrel
• Enhanced Oil Recovery (EOR) by injection of stripped CO2
Environmental Benefits
• UCG may not require an external water source to operate, a major environmental advantage over water-intensive coal mining operations and pulverised-coal-fired energy production methods
• Lower emissions, because gasification in UCG is underground thereby reducing environmental management costs
• Particulates are generated at half the rate of their surface equivalents and stay underground
• Lower fugitive dust, noise, visual impact on the surface
• Low risk of surface water pollution
• Reduced methane emissions - coal seam gas is recovered in the process, rather than lost in the atmosphere as in most conventional mining
• No dirt handling and disposal at mine sites
• No coal washing and fines disposal at mine sites
• Smaller surface footprints at power stations
• Lower water recovery and significant surface hazard liabilities on abandonment

In addition to these benefits, the linking of carbon capture and storage with underground coal gasification makes the argument for UCG even more compelling. Carbon dioxide can be stripped out of the syngas produced through gasification and reinjected into the very coal seam from which it was extracted, making for a carbon neutral energy cycle."

There is still much work to be done in the field of underground coal gasification. While it has been in commercial application in the Soviet Union for over 40 years, development elsewhere has been slow. But with the ever increasing need to reduce our carbon footprint, it seems like the time may be ripe for this technology to reach its full potential.

Scientific innovation is key to powering the future

BLUEFUELENERGY.COM: With the planet facing the double threat of global climate change brought on by greenhouse gas emissions and the depletion of the world's petroleum reserves, humankind has some choices to make. We can carry on as present and face both an energy crisis and a climatic crisis in the near future, we can drastically slow our consumption of energy thereby staving off these twin calamities but hobbling what we call modern civilization, or we can innovate to develop technologies that will both solve the threats we face and advance civilization.

Most people would agree that the choice to innovate and advance civilization is the most desirable, and it is always fascinating to see how innovation manifests itself. While the general population might consider the development of Blue Fuel/DME as an alternative fuel innovative in its own right, two recent announcements regarding innovations in the production of alternative fuels go a step further.

The first idea comes from the Institute of Bioengineering and Nanotechnology (IBN) in Singapore where scientists have demonstrated a method of converting CO2 into methanol via a non-toxic room-temperature process. In a media release they explain that "IBN scientists have made carbon dioxide react by using N-heterocyclic carbenes (NHCs), a novel organocatalyst. ...Hydrosaline, a combination of silica and hydrogen, is added to the NHC-activated carbon dioxide, and the product of this reaction is transformed into methanol by adding water through hydrolysis." Research is continuing to make the process even more cost-effective.

The second idea comes from scientists at the Norwegian University of Science and Technology. Their article, "Concentrating-Solar Biomass Gasification Process for a 3rd Generation Biofuel," was published in the online journal Environmental Science and Technology. The abstract states: "A new concept of producing synfuel from biomass using concentrated solar energy as its main energy source is proposed in this paper. The aim of the concept is to obtain an easy-to-handle fuel with near-zero CO2 emissions and reduced land-use requirements compared to first- and second-generation biofuels. The concept's key feature is the use of high-temperature heat from a solar concentrating tower to drive the chemical process of converting biomass to a biofuel, obtaining a near-complete utilization of carbon atoms in the biomass." An excellent synopsis of the paper can be found on the Green Car Congress website.

These are only two ideas, but they are representative of the widespread effort being put forth to develop innovative technologies to tackle some of the challenges facing the world today.