SWOT Analysis of Supercritical & Ultra-Supercritical Power Plants Strengths: High Thermal Efficiency Environment Friendly Significant breakthroughs in R&D Lower fuel cost per unit of power Run-of-Mine Coal can be directly used

Weaknesses: Materials Limitation High levels of corrosion Increased supervision and maintenance costs Limited scope for retrofitting opportunities

Opportunities: Vast Scope for Power Plant capacities based on Supercritical Technologies Ever increasing demand for power Optimum use and higher dependence on domestic sources of energy

Threats: R&D setbacks will restrict the growth Fossil Fuels are likely to be exhausted in not too distant a future More stringent environmental regulations Development of cheaper and more efficient sources of energy

CONCLUSION The current state-of-the-art for coal-fired supercritical steam cycles is –600C/300 bar maximum steam conditions, with a net thermal efficiency of about 45% (LHV, based on UK inland conditions). 620C plant are expected within five years while, in the longer term (10-20 years) C is expected, with resulting cycle efficiencies in the range 50-55%. Materials limitations are the major factors limiting further development, with key constraints at the furnace wall, superheater and reheater outlets, and the first stages of the HP and IP turbines. Considerable materials R&D is under way in Europe, Japan and the USA.

Other developments are under way, mostly by individual manufacturers to optimise cycle design and improve individual components, which are resulting in incremental improvements across the plant. Identified R&D needs include extensive materials research, particularly into the welding and corrosion properties of candidate high-temperature materials, and demonstration of a Benson vertical furnace tube.

No significant opportunities for retrofit of supercritical technology to existing (Predominately subcritical) plant have been identified. FBCs using supercritical steam cycles are now being developed. For example, a 350 MW PFBC is under construction in Japan.

The indications are that HRSGs will progressively move to once-through technology and then to supercritical pressures as GTs become larger and exhaust temperatures rise. The first full-scale subcritical demonstration Benson design HRSG is nearing completion in the UK. Supercritical technology is expected to progressively displace subcritical designs due to its better environmental performance and lower associated fuel costs. Asia is expected to generate the significant demand. Current estimates suggest a steady rise in new supercritical plant from 5GW pa now to perhaps 25-40GW pa in 20 years time.