Clean coal tech for the future

Another eco-friendly way is that of carbon capture and storage

Coal is a vital fuel in most parts of the world. Burning coal without adding to global carbon dioxide levels is a major technological challenge. The most promising ?clean coal? technology involves using the coal to make hydrogen from water, then burying the resultant carbon dioxide by-product and burning the hydrogen. The greatest challenge is bringing down the cost of this technology for ?clean coal? to compete with nuclear power on the basis of near-zero emissions for base-load power.

The clean coal technology is moving very rapidly in the direction of coal gasification with a second stage so as to produce a concentrated and pressurised carbon dioxide stream followed by its separation and geological storage. This technology has the potential to provide what may be called ?zero emissions??in reality, extremely low emissions of the conventional coal pollutants, and as low-as-engineered carbon dioxide emissions.

The US sees ?zero emissions? coal technology as a core element of its future energy supply in a carbon-constrained world. It had an ambitious programme to develop and demonstrate the technology and have commercial designs for plants with an electricity cost of only 10% greater than conventional coal plants available by 2012, but with the cancellation of FutureGen, this is in doubt.

Australia is very well-endowed with carbon dioxide storage sites near major carbon dioxide generation sources, but as elsewhere, demonstration plants will be needed to gain public acceptance and show that the storage is permanent. In several countries, ?zero emissions? technology seems to have the potential for low avoided cost for greenhouse gas emissions.

Another useful technology is that of carbon capture and storage (CCS). There are a range of technologies at different stages of research & development for proven safe and economical capture, transport, and storage of carbon dioxide to reduce its concentration in the atmosphere. There are three generic process routes for capturing carbon dioxide from fossil fuel combustion plant?pre-combustion capture, post-combustion capture and oxyfuel combustion.

Pre-combustion capture involves reacting fuel with oxygen or air and in some cases, steam to produce a gas consisting mainly of carbon monoxide, which is then reacted with steam in a catalytic shift converter to produce more hydrogen and carbon dioxide. The carbon dioxide is separated and the hydrogen is used as fuel in a gas turbine combined cycle plant. Post-combustion capture involves separation of carbon dioxide from flue gas. Oxyfuel combustion involves burning fuel in an oxygen/carbon dioxide mixture rather than air to produce a carbon dioxide rich flue gas.

Out of India?s annual 1.2 gigatonne of carbon dioxide emissions, the power sector is responsible for over half. Therefore, there is a need to switch over to the use of clean coal technologies. India has also urged the UNFCC that the developed countries speed up clean technology transfer to developing countries and raise the needed fund to the level of over $80 billion.

The clean coal technologies would help bring down emissions in India and thus help ease global concerns as India?s primary energy demand is likely to increase four-fold if the country has to attain and sustain high growth and meet the needs of the growing population. The International Energy Agency (IEA) has estimated that India?s primary energy demand will multiply three to four times, and agreeing on this projection, the Planning Commission has estimated that the country?s primary energy need will increase from 542 tonne of oil equivalent in 2006 to 842 million tonne oil equivalent in 2016 and finally to 1836 million tonne oil equivalent in 2031. This would push India from the rank of the fourth largest energy consumer in the world today to the third largest by 2030, after China and the US.

Greenhouse gas induced global climate change is primarily due to excessive energy use. However, India has a low national average per capita carbon dioxide emission of 1.67 tonne significantly below US’s 23 tonne and Europe’s 11 tonne. The Rio Declaration has accepted the principle of “common but differentiated responsibilities” of developed countries vis-?-vis developing countries in combating climate change.

Developing countries and economies in transition like India has the right to develop and meet the needs of its people. India has urged in the United Nations Framework Convention on Climate Change (UNFCC) for fixing global emission target on basis of per capita emission.

There are projections that India with a 1.13 billion people today may become the most populous nation by 2030. Energy demand would, therefore likely to increase if the country has to attain and sustain a double-digit growth rate in the economy. In this context, IEA’s projection of three to four times increase in India’s primary energy demand looks realistic. India has already committed itself to combating climate change at home and has initiated a series of measures. As coal is a major source of energy, the use of clean coal technology seems appropriate.