Archive for the ‘Coal use’ Category

Clean energy critically needs clean coal

December 19, 2011 1 comment

In the recently concluded COP 17 in Durban, a less well known outcome was the addition of Carbon Capture and Sequestration (CCS) as a Clean Development Mechanism (CDM) project.

The addition of CCS was a major coup for coal lobbyists. Although it was not a desired outcome for environmentalists, the use of coal as a major energy source is here to stay. First for the facts – coal in 2010 supplies almost 30% of the world primary energy needs – 12 billion toe (from bp energy outlook 2011). China itself generates more than half its electricity from coal burning.

By 2030, the world energy demand is expected to increase 45%. Whilst there will be an increasing use of renewables and gas, this is not expected to displace coal as a major energy source. Coal as a percentage supply of primary energy is expected to decrease only marginally to 26%. (Source: bp)

The recent Fukushima nuclear accident has further shifted nuclear energy dependence to other sources of energies including renewables and gas. Wind and solar energy – the two main forms of renewables are intermittent sources of energies and cannot fully compensate nuclear energy as a base load. The tapping onto the reserves of unconventional gas – that of coal bed methane and shale gas has been offered as a solution, although the environmental impact of hydraulic fracking for shale gas is presently under investigation.

A portfolio approach of reducing emissions is thence the only solution forward – that of broadening the energy source base to low emissions fuels, energy policies (taxation and cap and trade) and increasing energy efficiency. A policy scenario target motioned by the IEA is to limit atmospheric concentration to 450 ppm of carbon dioxide and thence temperature rise to not more than a critical threshold of 2 degree Celsius1. This has been remarked as ‘hard to achieve’ due to the lock-in of existing infrastructure (eg power and industrial plants and use of fossil fuels in existing car fleet).  In a New Scenario policy report (in the World Energy Outlook 2011 by IEA), CO2 emissions is expected to reach 35 Gt in 2035 resulting in a 650 ppm CO2 concentration and a temperature rise of 3.5 deg Celsius. CCS is a swing measure that has been identified as a critical technology to reduce emissions from coal power plants by the IPCC 4th assessment report.

CCS is not a new technology having been used to enhance recoveries in oil fields. However its use in coal fired power plants has not been commercially tested, albeit pilot plants are in USA and Norway. See the world coal association link on available CCS technologies. In China, coal fired plants alone contributed 6.5 Gt of total 7.7 Gt carbon dioxide emission in 2009. In its latest 5-year Plan in Apr’ 11, an objective of the government is the reduction of environmental pollution. This can be substantially achieved through the replacement of inefficient and pollutive coal power plants. By including CCS to the list of CDM additionality projects, the private sector can also be economically motivated to modernise existing coal plants in developing countries. These measures will hasten the commercialisation of CCS through technological learning by doing. CCS can presently be classified as a ‘back-stop technology’.

The use of coal for power generation is here to stay for the foreseeable decades, and a pointed policy measure is to use it in a sustainable manner.

1 – this was purported in the IPCC 4th AR, although the climate science linkage has been disputed recently.