Who Has the World’s Most Efficient Coal Power Plant Fleet?

A comparison of coal power plant fleets from China, the European Union (EU), Japan, and the U.S. by the International Energy Agency's (IEA's) Clean Coal Centre yields surprising insights into efforts these regions are making to deploy high-efficiency, low-emission (HELE) plants.

1. Clean coal crown. Unit 2 at J-POWER's Isogo Thermal Power Station, a 600-MW ultrasupercritical unit in Yokohama, Japan, ranks as the cleanest coal-fired power plant in the world in terms of emission intensity, with levels comparable to those from a natural gas-fired combined cycle plant. According to the International Energy Agency's Clean Coal Centre, the unit's average emissions are in the single digits for NOx and SO2, and less than five milligrams per cubic meter for particulate matter. Courtesy: J-POWER

The December 2016-released report, "An overview of HELE deployment in the coal power plant fleets of China, EU, Japan and USA," compares data from existing plants of 300 MW or larger, as well as those under construction and planned. It also sizes them up according to deployed technology, age, and installed pollution control equipment.

It concludes that the coal fleet in Japan is the most efficient in the world, followed by China, the EU, and finally, the U.S.

Japan Leads the Pack. Japan's fleet, which is relatively young as the report notes, has an average operational efficiency of 41.6%, calculated using lower heating value (LHV, net; as are efficiency values given below). Most coal plants in Japan's fleet are HELE plants. According to the report, Japan also hosts the world's "cleanest" coal-fired power plant in terms of emissions intensity: Unit 2 at J-POWER's Isogo Thermal Power Station (Figure 1), a 600-MW ultrasupercritical unit in Yokohama, which began commercial operations in July 2009. (The project was a POWER Top Plant in October 2010).

China Is Not Far Behind.In China, a government crackdown to shackle rampant air pollution and shutter small, aging, and less-efficient coal plants, as well as soaring investments in research and development (R&D) of advanced coal technology, have transformed its energy sector, the IEA says. The country's coal-fired fleet has an average operational efficiency of 38.6%-higher than the average across IEA member countries. R&D, notably, allowed the country to design and build the double-reheat 1,000-MW ultrasupercritical Guodian Taizhou II Unit 3, the IEA says. The unit has been in operation since September 2015, and it reaches an efficiency of 47.82%, the highest globally for a double-reheat plant. The IEA also notes: "Every Chinese power plant is equipped with [particulate matter] and SO2 control equipment, and almost all have NOx removal devices. All coal-fired plants will have to be ultra-low-emission by 2020." The agency pegs China's successes on the rapid implementation of tight environmental and performance standards, combined with available finance for coal-fired projects and subsidies for energy generated from ultra-low emission power plants. The country is facing critical barriers to an expansion of its coal fleet, however, owing to power overcapacity, competition for limited water resources in some areas, localized pollution control, and a surge in the development of renewables, "which can reduce the profitability of coal-fired power plants," the IEA says.

The EU Is Weighed Down by an Aging Fleet. Several countries in the EU have moved to phase out coal entirely (See "The Big Picture" in POWER's March 2017 issue), and few new coal-fired plants are being planned and built. However, the bloc's average coal-fired plant efficiency is a noteworthy 38%, even though a significant proportion of its fleet is relatively old, the IEA says. One of the EU's most advanced coal-fired plants is the 1,100-MW ultrasupercritical Maasvlakte Power Plant 3 in the Netherlands. That unit, which entered service in 2015, has an efficiency of 47%. It can cofire up to 30% biomass, is carbon-capture ready, and can supply district heat.

The EU will require all coal-fired power plants that operate after 2030 to employ carbon-capture-and-storage technology, the IEA notes. However, while the EU is conducting notable research and development on advanced ultrasupercritical technology, construction of new coal-fired power plants in the EU could be hindered by a low carbon price under the emissions trading system.

Efficiency Lags in U.S., but Future Is Promising. As this story goes into production in early March, startup and commissioning activities continued at the Kemper County Integrated Gasification Combined Cycle facility in Mississippi. No other coal plants are under construction in the U.S. The nation's coal fleet has instead seen a marked move toward pollution control systems for NOx, SOx, and particulate matter, driven largely by regulations, the IEA says. But the fleet is still dominated by relatively old units, both subcritical and supercritical. Its average efficiency is around 37.4%. The most efficient coal-fired unit in the country is the 665-MW John Turk Jr. plant in Arkansas ( POWER's Plant of the Year in 2013), which achieves an efficiency of 42%. It is the nation's only ultrasupercritical unit.

However, this January, NRG Energy and JX Nippon Oil and Gas Exploration Corp. began operation of the Petra Nova project, the world's largest commercial post-combustion carbon capture system. The IEA notes that various other carbon-capture projects are under way. R&D on advanced ultrasupercritical, hybrid coal, and oxycombustion and chemical-looping combustion is also ongoing. "As coal is still predicted to have a significant place in the future energy mix of the USA (21% in 2030 and 18% in 2040) it is possible that once new technologies are demonstrated, old coal-fired units could be replaced with new systems," the IEA concludes optimistically. "Additionally, with a market for CO2 in enhanced oil recovery (EOR), relevant R&D, tax incentives and federal support for carbon capture, utilisation and storage, the USA is currently a leader in these areas."

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