fleet of power tong trucks factory

A two-speed Hydra-Shift® motor coupled with a two-speed gear train provides (4) torque levels and (4) RPM speeds. Easily shift the hydraulic motor in low speed to high speed without stopping the tong or tublar rotation, saving rig time.

Used on corrosion resistant alloys (CRA) and fiberglass tubulars where reduced markings on the tubular is desired. Eckel"s Coated True Grit® Dies utilize Tungsten Carbide grit which provides many more points of contact on the surface of the tubular than our Pyramid Fine Tooth dies.

A patented door locking system (US Patent 6,279,426) for Eckel tongs that allows for latchless locking of the tong door. The tong door swings easily open and closed and locks when torque

is applied to the tong. When safety is important this locking mechanism combined with our safety door interlock provides unparalleled safety while speeding up the turn around time between connections. The Radial Door Lock is patented protected in the following countries: Canada, Germany, Norway, United Kingdom, and the United States.

The WD Tri-Grip® Backup is a high performance no compromise backup that is suitable for make-up and break-out of the most demanding connections. The WD Tri-Grip®Backup features a three head design that encompasses the tubular that applies an evenly distributed gripping force. The WD Tri-Grip®is a high performance backup with no compromises that is available for specific applications that provdies exceptional gripping capabilities with either Eckel True Grit® dies or Pyramid Fine Tooth dies.

The field proven Tri-Grip® Backup features a three head design that encompasses the tubular that applies an evenly distributed gripping force. The Tri-Grip®Backup provides exceptional gripping capabilities with either Eckel True Grit® dies or Pyramid Fine Tooth dies. The hydraulic backup is suspended at an adjustable level below the power tong by means of three hanger legs and allowing the backup to remain stationary while the power tong moves vertically to compensate for thread travel of the connection.

Eckel offers several models of torque control systems that are used to monitor the torque turn values when making up tubular connections (Tubing, Casing, & Drill Pipe). Any flaws in the make-up process will be readily shown in a graph.

Offshore Energy Services, Inc. (OES), answering to the ever-changing tubular connection design, has continued to meet the market demand by upgrading our Hydraulic Power Tong fleet.

We have multiple size and torque ranges available. The tubular size ranges we are capable of handling are 36" through 4-1/2" with torques up to 150,000 ft./lbs.

Dutch Casing Services has continually expanded our fleet of power tong equipment since our inception in 1999. We take great pride in consistently delivering a superior service experience to our clients. Attention to the details and regular maintenance in conjunction with proper training and certifications guarantees our equipment is operated in the safest manner on your jobsite.

Our experienced and skilled power tong technicians play a major role in the safety and efficiency of a casing run. This makes the selection of your power tong service company a key component of overall performance.

ProTorque attracts and employs some of the industry’s most talented and experienced casing running technicians. Every detail of a casing run must be considered when looking for cost savings and efficiency; particularly on long production strings where every second counts while maintaining a safe operation. When making-up hundreds of connections, filling on the fly and selecting the correct handling equipment (air or hydraulic powered slips); we save time and effort on long challenging casing runs. ProTorque can meet handling requirements of up to 500 tons of hoist capability.

GIANT Power Tongs was established in the summer of 2008 to serve northeastern BC and northern Alberta. We are members in good standing with ISNetworld, Complyworks and Secor. We run a fleet of 6 tong trucks based out of Fort St John. We can run all tubing and casing from 60.3mm to 339.7mm. Call us anytime for all your powertong, threadwashing, torque monitoring or thread inspection needs.

Today we operate a medium fleet of power tong and service trucks including a full line of casing and tubing running services from surface to production.

Safety performance is the #1 goal. We won’t do the work if we can’t do it safely. Doing is safe means that everyone goes home at the end of the day. This is our belief and our safety culture.

A municipal utility partnered with Volta and Palfinger on aerial truck with an all-electric auxilliary power system that cut 70%+ of vehicle emissions. The truck will reach ROI in under two years from fuel and maintenace savings.

This article is about the specifics of power stations which burn coal. For comparison with power stations which burn fuels such as natural gas, see fossil fuel power station. For information common to all power stations which convert heat into electricity, see thermal power station.

A coal-fired power station or coal power plant is a thermal power station which burns coal to generate electricity. Worldwide there are over 2,400 coal-fired power stations, totaling over 2,000 gigawatts capacity.world"s electricity,air pollution.

A coal-fired power station is a type of fossil fuel power station. The coal is usually pulverized and then burned in a pulverized coal-fired boiler. The furnace heat converts boiler water to steam, which is then used to spin turbines that turn generators. Thus chemical energy stored in coal is converted successively into thermal energy, mechanical energy and, finally, electrical energy.

Coal-fired power stations emit over 10 Gt of carbon dioxide each year,greenhouse gas emissions, so are the single largest cause of climate change.costs to other people due to the health and environmental impact of the coal industry are not priced into the cost of generation,stranded assets.UN Secretary General has said that OECD countries should stop generating electricity from coal by 2030, and the rest of the world by 2040.

The first coal-fired power stations were built in the late 19th century and used reciprocating engines to generate direct current. Steam turbines allowed much larger plants to be built in the early 20th century and alternating current was used to serve wider areas.

Coal is delivered by highway truck, rail, barge, collier ship or coal slurry pipeline. Generating stations are sometimes built next to a mine; especially one mining coal, such as lignite, which is not valuable enough to transport long-distance; so may receive coal by conveyor belt or massive diesel-electric-drive trucks. A large coal train called a "unit train" may be 2 km long, containing 130-140 cars with around 100 tonnes of coal in each one, for a total load of over 10000 tonnes. A large plant under full load requires at least one coal delivery this size every day. Plants may get as many as three to five trains a day, especially in "peak season" during the hottest summer or coldest winter months (depending on local climate) when power consumption is high.

Shorter trains may use railcars with an "air-dump", which relies on air pressure from the engine plus a "hot shoe" on each car. This "hot shoe" when it comes into contact with a "hot rail" at the unloading trestle, shoots an electric charge through the air dump apparatus and causes the doors on the bottom of the car to open, dumping the coal through the opening in the trestle. Unloading one of these trains takes anywhere from an hour to an hour and a half. Older unloaders may still use manually operated bottom-dump rail cars and a "shaker" attached to dump the coal.

A collier (cargo ship carrying coal) may hold 41,000 tonnes (40,000 long tons) of coal and takes several days to unload. Some colliers carry their own conveying equipment to unload their own bunkers; others depend on equipment at the plant. For transporting coal in calmer waters, such as rivers and lakes, flat-bottomed barges are often used. Barges are usually unpowered and must be moved by tugboats or towboats.

As a type of thermal power station, a coal-fired power station converts chemical energy stored in coal successively into thermal energy, mechanical energy and, finally, electrical energy. The coal is usually pulverized and then burned in a pulverized coal-fired boiler. The heat from the burning pulverized coal converts boiler water to steam, which is then used to spin turbines that turn generators. Compared to a thermal power station burning other fuel types, coal specific fuel processing and ash disposal is required.

For units over about 200 MW capacity, redundancy of key components is provided by installing duplicates of the forced and induced draft fans, air preheaters, and fly ash collectors. On some units of about 60 MW, two boilers per unit may instead be provided. The hundred largest coal power stations range in size from 3,000MW to 6,700MW.

In plants that burn pulverized coal, silos feed coal to pulverizers (coal mills) that take the larger 5 cm pieces, grind them to the consistency of talcum powder, sort them, and mix them with primary combustion air, which transports the coal to the boiler furnace and preheats the coal in order to drive off excess moisture content. A 500 MWe plant may have six such pulverizers, five of which can supply coal to the furnace at 250 tonnes per hour under full load.

In plants that do not burn pulverized coal, the larger 5 cm pieces may be directly fed into the silos which then feed either mechanical distributors that drop the coal on a traveling grate or the cyclone burners, a specific kind of combustor that can efficiently burn larger pieces of fuel.

Plants designed for lignite (brown coal) are used in locations as varied as Germany, Victoria, Australia, and North Dakota. Lignite is a much younger form of coal than black coal. It has a lower energy density than black coal and requires a much larger furnace for equivalent heat output. Such coals may contain up to 70% water and ash, yielding lower furnace temperatures and requiring larger induced-draft fans. The firing systems also differ from black coal and typically draw hot gas from the furnace-exit level and mix it with the incoming coal in fan-type mills that inject the pulverized coal and hot gas mixture into the boiler.

The ash is often stored in ash ponds. Although the use of ash ponds in combination with air pollution controls (such as wet scrubbers) decreases the amount of airborne pollutants, the structures pose serious health risks for the surrounding environment.liners, especially in the United States, and therefore chemicals in the ash can leach into groundwater and surface waters.

Since the 1990s, power utilities in the U.S. have designed many of their new plants with dry ash handling systems. The dry ash is disposed in landfills, which typically include liners and groundwater monitoring systems.

Fly ash is captured and removed from the flue gas by electrostatic precipitators or fabric bag filters (or sometimes both) located at the outlet of the furnace and before the induced draft fan. The fly ash is periodically removed from the collection hoppers below the precipitators or bag filters. Generally, the fly ash is pneumatically transported to storage silos and stored on site in ash ponds, or transported by trucks or railroad cars to landfills,

At the bottom of the furnace, there is a hopper for collection of bottom ash. This hopper is kept filled with water to quench the ash and clinkers falling down from the furnace. Arrangements are included to crush the clinkers and convey the crushed clinkers and bottom ash to on-site ash ponds, or off-site to landfills. Ash extractors are used to discharge ash from municipal solid waste–fired boilers.

A well-designed energy policy, energy law and electricity market are critical for flexibility.dispatchable generation than most gas-fired power plants. The most important flexibility is low minimum load,renewable energy with batteries.

In 2020 worldwide 2059 GW of coal power was operational, 50 GW was commissioned, and 25 GW started construction (most of these three in China); and 38 GW retired (mostly USA and EU).

There are 4 main types of coal-fired power station in increasing order of efficiency are: subcritical, supercritical, ultra-supercritical and cogeneration (also called combined heat and power or CHP).

Integrated gasification combined cycle (IGCC) is a coal power generation technology that uses a high pressure gasifier to turn coal (or other carbon based fuels) into pressurized gas—synthesis gas (syngas). Converting the coal to gas enables the use of a combined cycle generator, typically achieving high efficiency. The IGCC process can also enable removal of some pollutants from the syngas prior to the power generation cycle. However, the technology is costly compared with conventional coal-fired power stations.

As coal is mainly carbon, coal-fired power stations have a high carbon intensity. On average, coal power stations emit far more greenhouse gas per unit electricity generated compared with other energy sources (see also life-cycle greenhouse-gas emissions of energy sources). In 2018 coal burnt to generate electricity emitted over 10 Gt CO22e

From 2015 to 2020, although coal generation hardly fell in absolute terms, some of its market share was taken by wind and solar.UN Secretary General has said that OECD countries should stop generating electricity from coal by 2030 and the rest of the world by 2040, otherwise limiting global warming to 1.5 °C, a target of the Paris Agreement, would be extremely difficult.

Ammonia has a high hydrogen density and is easy to handle. It can be used as storing carbon-free fuel in gas turbine power generation and help significantly reduce CO₂ emissions as a fuel.sustainable shipping, which unlike electricity generation, has few other clean options.

Damage to health from particulates, sulphur dioxide and nitrogen oxide occurs mainly in Asia and is often due to burning low quality coal, such as lignite, in plants lacking modern flue gas treatment.

Mercury emissions from coal-fired power plants can fall back onto the land and water in rain, and then be converted into methylmercury by bacteria.biomagnification, this mercury can then reach dangerously high levels in fish.

Coal-fired power plants also emit sulfur dioxide and nitrogen.acid rain, which can restructure food webs and lead to the collapse of fish and invertebrate populations.

Coal power plants tend to serve as base load technology, as they have high availability factors, and are relatively difficult and expensive to ramp up and down. As such, they perform poorly in real-time energy markets, where they are unable to respond to changes in the locational marginal price. In the United States, this has been especially true in light of the advent of cheap natural gas, which can serve as a fuel in dispatchable power plants that substitute the role of baseload on the grid.

In India capacity factors are below 60%.capacity factor of 40%; that is, they operated at a little less than half of their cumulative nameplate capacity.

If global warming is limited to well below 2 °C as specified in the Paris Agreement, coal plant stranded assets of over US$500 billion are forecast by 2050, mostly in China.Carbon Tracker estimated that 39% of coal-fired plants were already more expensive than new renewables and storage and that 73% would be by 2025.

The energy policy of China regarding coal and coal in China are the most important factors regarding the future of coal-fired power stations, because the country has so many.

Cropper, Maureen; Cui, Ryna; Guttikunda, Sarath; Hultman, Nate; Jawahar, Puja; Park, Yongjoon; Yao, Xinlu; Song, Xiao-Peng (2 February 2021). "The mortality impacts of current and planned coal-fired power plants in India". Proceedings of the National Academy of Sciences. 118 (5). Bibcode:2021PNAS..11817936C. doi:ISSN 0027-8424. PMC PMID 33495332.

"China generated over half world"s coal-fired power in 2020: study". . Retrieved 14 September 2021. China generated 53% of the world"s total coal-fired power in 2020, nine percentage points more that five years earlier

U.S. Environmental Protection Agency (EPA), Washington, D.C. (21 June 2010)."Hazardous and Solid Waste Management System; Identification and Listing of Special Wastes; Disposal of Coal Combustion Residuals From Electric Utilities; Proposed rule." Federal Register, 75 FR 35151

Scott, Allan N.; Thomas, Michael D. A. (January–February 2007). "Evaluation of Fly Ash From Co-Combustion of Coal and Petroleum Coke for Use in Concrete". ACI Materials Journal. Farmington Hills, MI: American Concrete Institute. 104 (1): 62–70. doi:10.14359/18496.

NAGATANI Genichiro; ISHII Hiroki; ITO Takamasa; OHNO Emi; OKUMA Yoshitomo (January 2021). "Development of Co-Firing Method of Pulverized Coal and Ammonia to Reduce Greenhouse Gas Emissions" (PDF). . Retrieved 8 November 2021.

Tong, Dan; Zhang, Qiang; Liu, Fei; Geng, Guannan; Zheng, Yixuan; Xue, Tao; Hong, Chaopeng; Wu, Ruili; Qin, Yu (6 November 2018). "Current Emissions and Future Mitigation Pathways of Coal-Fired Power Plants in China from 2010 to 2030". Environmental Science & Technology. 52 (21): 12905–12914. Bibcode:2018EnST...5212905T. doi:10.1021/acs.est.8b02919. ISSN 0013-936X. PMID 30249091. S2CID 206581545.

Manych, Niccolò; Steckel, Jan Christoph; Jakob, Michael (March 2021). "Finance-based accounting of coal emissions". Environmental Research Letters. 16 (4): 044028. Bibcode:2021ERL....16d4028M. doi:ISSN 1748-9326.

Saygin, Deger; Rigter, Jasper; Caldecott, Ben; Wagner, Nicholas; Gielen, Dolf (31 May 2019). "Power sector asset stranding effects of climate policies". Energy Sources, Part B: Economics, Planning, and Policy. 14 (4): 99–124. doi:10.1080/15567249.2019.1618421. S2CID 191757913.

Ren, Mengjia; Branstetter, Lee; Kovak, Brian; Armanios, Daniel; Yuan, Jiahai (16 March 2019). "China overinvested in coal power: Here"s why". VoxEU.org. Retrieved 6 July 2019.

Urpelainen, Johannes; Zucker, Noah; Clark, Richard (11 April 2019). "Political Institutions and Pollution: Evidence from Coal-Fired Power Generation". Rochester, NY. SSRN 3370276. Cite journal requires |journal= (help)

Beijing is stuck between a rock and a hard place. On the one hand, China cannot eradicate coal-fired power from its energy mix overnight. China has not yet figured out how to develop its own natural gas supplies—which are more difficult to access and therefore more expensive than those in the United States—and renewable energy expansion takes time. On the other hand, Chinese citizens are demanding cleaner air, and they want immediate improvements. Air quality is now a political priority for the Chinese Communist Party on par with economic growth and corruption. This means that China cannot continue to run the same high-pollution coal plants that were considered acceptable decades ago. Beijing’s solution is to move full speed ahead with renewables while simultaneously investing in what may become the most efficient, least polluting coal fleet the world has ever seen.

Not all coal-fired power is created equal. Emissions and efficiency—the latter being the amount of coal consumed per unit of power produced, which also affects emissions—vary dramatically based on the type of coal and coal-burning technology used. What many U.S. analyses of China’s coal sector overlook is the fact that Beijing has been steadily shutting down the nation’s older, low-efficiency, and high-emissions plants to replace them with new, lower-emitting coal plants that are more efficient that anything operating in the United States.

To better understand where China’s coal fleet is going, CAP compared the top 100 most efficient coal-fired power units in the United States with the top 100 in China. (see Tables A1 and A2) The difference is astounding.

Compared with the Chinese coal fleet, even the best U.S. plants are running older, less efficient technologies. Coal-fired power plants can generally be broken down into three categories:

Subcritical: In these conventional power plants, coal is ignited to boil water, the water creates steam, and the steam rotates a turbine to generate electricity.3 The term “subcritical” indicates that internal steam pressure and temperature do not exceed the critical point of water—705 degrees Fahrenheit and 3,208 pounds per square inch.4

Supercritical: These plants use high-tech materials to achieve internal steam temperatures in the 1,000–1,050 degrees Fahrenheit range and internal pressure levels that are higher than the critical point of water, thus spinning the turbines much faster and generating more electricity with less coal.5

The U.S. coal fleet is much older than China’s: The average age of operating U.S. coal plants is 39 years, with 88 percent built between 1950 and 1990.7 Among the top 100 most efficient plants in the United States, the initial operating years range from 1967 to 2012. In China, the oldest plant on the top 100 list was commissioned in 2006, and the youngest was commissioned in 2015.

The United States only has one ultra-supercritical power plant.8 Everything else is subcritical or, at best, supercritical. In contrast, China is retiring its older plants and replacing them with ultra-supercritical facilities that produce more energy with less coal and generate less emissions as well. Out of China’s top 100 units, 90 are ultra-supercritical plants.

When the capacity of each of the top 100 units in each nation is taken into account, ultra-supercritical technology accounts for 92 percent of Chinese top 100 capacity and less than one percent—0.76 percent—of U.S. top 100 capacity. Because the technological makeup of the Chinese plants is different, their emissions levels are different as well. In the United States, the total nameplate capacity of our top 100 most efficient coal-fired power units is 80.1 gigawatts, and their cumulative annual carbon emissions amount to 361,924,475 metric tons.9 Meanwhile, the total nameplate capacity of China’s top 100 units is 82.6 gigawatts, and their cumulative annual carbon emissions are an estimated 342,586,908 metric tons.10 Since China’s fleet uses more advanced technology, it also consumes less coal: an average of 286.42 grams of coal equivalent, or gce, consumed per kilowatt-hour of power produced in China versus 374.96 gce consumed per kilowatt-hour produced at lower heating value in the United States.

To be sure, China still has plenty of older coal-fired power units that are not using the most advanced technology. According to the latest third-party research from S&P Global Platts, which provides research on global energy infrastructure, when the data set is expanded to include all operating coal-fired power capacity in China—which totals 920 gigawatts—approximately 19 percent uses ultra-supercritical technology, 25 percent uses supercritical technology, and 56 percent uses subcritical technology.11 However, the new builds are increasingly ultra-supercritical plants, and Beijing is steadily ratcheting up the emissions requirements and efficiency standards for those older plants as well.

By 2020, every existing coal-fired power unit in China must meet an efficiency standard of 310 gce per kilowatt-hour; any units that do not meet that standard by 2020 will be retired. In contrast, none of the current top 100 most efficient U.S. coal-fired power units would meet that same efficiency standard today. (see Table A2)

The simple fact is that the United States has a wide array of cheap and abundant energy options that now compete with coal-fired electricity generation—particularly shale gas and renewables. Given the additional context of falling U.S. electricity demand and improving efficiency, even U.S. electric utility executives have indicated that their business models are rebalancing toward these options—and away from coal.12 Although higher-tech plants, such as ultra-supercritical plants, have lower operation and maintenance costs than their less efficient counterparts, overnight capital costs are, on average, around 17 percent higher.13 In a market where even the least expensive coal-fired plants are struggling to compete with shale-gas-fired plants, those investments do not make good financial sense.

One thing China’s experience makes very clear is that even if the United States were to invest in newer, more efficient coal plants, it would not be a major jobs generator on par with renewable energy. As China’s power plants are becoming more efficient in their energy consumption and emissions, they are also becoming more efficient in terms of labor. The CAP research team visited the Shanghai Waigaoqiao No. 3 power station. That plant runs two 1,000 megawatt ultra-supercritical units and supports 250 employees.14 In contrast, the nearby Waigaoqiao No. 1 and Shidongkou No. 1 power stations each run four 300 megawatt subcritical units and employ 600 people and 1,000 people, respectively.15

The same thing is happening in China’s coal mines. As the operations become higher tech, they become cleaner and more efficient, and those jobs decrease as well. This is one reason Beijing expects its coal sector to lay off 1.3 million workers from 2016 to 2020.16 Chinese leaders view renewable energy as a much more dependable employment generator; they expect the nation’s renewable sectors to generate 13 million new jobs by 2020.17

China’s energy employment shifts follow a pattern that has been unfolding in the United States for decades. U.S. coal mining employment peaked in the 1920s and then began a long and steady decline. From 1983 to 2014, U.S. coal production increased more than 28 percent, but employment still fell 59 percent.18 This reflects a shift in U.S. coal production from more labor-intensive underground mining in the eastern United States to more highly mechanized and easily accessible surface mining in the west.19 Falling U.S. electricity demand, rising energy efficiency, and sharp price drops for natural gas, solar, and wind compounded U.S. energy employment shifts by reducing utilities’ dependence on and demand for coal.20 At year-end 2016, the United States had a total of 54,030 coal operator employees nationwide.21 In contrast, between 2015 and 2016, the United States added 73,615 new jobs in solar energy generation—a nearly 25 percent year-on-year increase—bringing the total number of U.S. solar energy generation jobs to 373,807 nationwide.22

Specifically, GCAM takes in assumptions about population growth and changes in labor productivity, along with representations of resources, technologies, and policies, and solves for the equilibrium prices and quantities of various energy, agricultural, and GHG markets in each five-year period from 2010 (the calibration year) to 2100 at different spatial resolutions. Primary energy (i.e., coal and other fossil fuels), agricultural products, and biomass are traded globally. GCAM tracks emissions of sixteen GHGs, aerosols, and short-lived species endogenously based on the resulting energy, agriculture, and land systems activity. Emissions are then passed to the climate carbon-cycle module and converted to concentrations, radiative forcing, temperature, and other responses to the climate system

Here, we use a special version of GCAM that provides sub-national details in the energy markets for China. Specifically, in GCAM-China, the world economy and energy systems operate across 31 geo-political regions plus the further disaggregated 31 province-level sub-regions of mainland China

Electricity demand of each province is driven by increased electrification in buildings, industrial, and transportation sectors. Each province also has its own electricity supply system. The electricity sector includes a detailed representation of different power generation technologies, including those fueled by coal and other fossil fuels (with and without CCS), bioenergy (with and without CCS), nuclear, and renewables. Cost data of different technologies is based on NREL Annual Technology Baseline data

The top-down and bottom-up coal pathways are almost identical for the Central China Grid and China Southern Power Grid (Supplementary Fig. 7b). This indicates that these two grids can follow our plant-by-plant retirement schedule and meet future demand without trading electricity with other regions. In contrast, the bottom-up coal retirement is faster than the top-down phaseout in the North China Grid and Northeast China Grid but slower in the Northwest China Grid and East China Grid (Supplementary Fig. 7b). These differences could be addressed by increased investment in clean energy technologies or through long-distance transmission. For example, the Northwest China Grid and East China Grid could export electricity to other regions, while the North China Grid and Northeast China Grid could import electricity.

Using GCAM-China, we develop two deep decarbonization scenarios by limiting end-of-century radiative forcing at different levels. Specifically, a well-below 2 °C and a 1.5 °C scenario, has the end-of-century radiative forcing at 2.6 Wm−2 and 2.0 Wm−2, respectively. Starting in the model period of 2025, we apply an increasing global carbon price on fossil fuel energy-related emissions across regions and sectors that is consistent with the well-below 2 °C or 1.5 °C temperature goal. This carbon price is applied to all regions and all sectors of the economy and emission reductions occur where it’s economical. Therefore, our results show how much mitigation would happen in the power sector with all other sectors mitigating at the same marginal abatement costs. The implication of different sectoral policies is an important research topic but beyond the scope of this research. However, we note that the literature generally points to the importance of decarbonizing the electricity sector early and quickly, especially given that mitigation pathways in other sectors frequently involve electrification. Reflecting institutional difficulties associated with pricing carbon in land, only 10% of the carbon price is passed on to the land sector.

We exogenously specify 2010, 2015, and 2020 coal power generation for each vintage group by province to match historical data and our plant-by-plant dataset. We categorize every coal power plant in a given province into seven categories (vintages) depending on when they started operation: 1975 (or before), 1976–1990, 1991–1995, 1996–2000, 2001–2005, 2005–2010, and beyond 2010.

Historical data up to 2010 is calibrated natively in GCAM. We exogenously specify the 2015 generation of older vintages to the historical value. For estimating the 2020 generation for the older vintages, we use the following procedure. First, we assume that the 2018 aggregate coal-fired power plant generation value will hold true for 2020. Second, we subtract the estimated 2020 generation for the “Beyond 2010” vintage to obtain the total aggregated generation for all the older vintages. Third, we assume that the ratio of contribution of each vintage to the aggregate generation will be the same as 2015. Finally, we adjust the s-curve generation between 2015 and 2020 reflecting these assumptions.

For the new “Beyond 2010” vintage, we exogenously specify the 2015 vintage to the historical values, and 2020 vintages to those currently under construction. We assume the 2015 generation values to hold true for 2020 for power plants that were operating between 2011 and 2015. We calculate projected generation from power plants that started operation (or were expected to do so in the case of dates beyond 2018) between 2016 and 2020. We add the two values to obtain an expected “Beyond 2010” vintage 2020 generation value for each province.

For 2020, total coal power generation is matched with 2018 data. Since the model runs at a five-year interval, we use 2018 generation data to approximate the trend between 2015 and 2020. Starting in the next model period of 2025, the model finds the most cost-effective pathways to achieve the 1.5 °C or 2 °C climate targets through a global carbon price. When converting to the coal plants retirement pathways (GW), our baseline value is based on the plant-level data up to May 2019, and we used a linear interpolation between the 2019 data and the first model period in 2025, and between all model periods thereafter, to calculate the annual retirement pathways.

Our scenario shows that both global and China’s net CO2 emissions peak around 2020, and then China reaches net-zero emissions by 2055 under 1.5 °C and by 2070 under 2 °C, while the world reaches net-zero carbon five years earlier under each target (Fig. 5a, b). This is associated with global and China conventional coal power generation also peaking in 2020, and being phased out around 2040 and 2050, under 1.5 °C and 2 °C, respectively (Fig. 5c, d). China’s total power generation will increase to about 12,500 TWh under 2 °C and to about 14,500 TWh under 1.5 °C by 2050, mainly supplied by solar and other renewable energies (Fig. 5c).

a Global net CO2 emission pathways, b China net CO2 emission pathways, c global conventional coal power generation pathways, d China conventional coal power generation pathways, and e China electricity generation by technology. The lighter lines are scenarios from the IAMC 1.5 °C Scenario Explorer. The light blue lines indicate scenarios categorized as “Below 1.5 °C”, “1.5 °C low overshoot”, and “1.5 °C high overshoot”; the light green lines indicate scenarios categorized as “Lower 2 °C” and “Higher 2 °C” in the database.

When comparing the global pathways from our scenarios against the ensembles from the IPCC 1.5 °C database5a, c); however, the 1.5 °C database does not provide regional specific results for China, making a direct comparison more challenging. Nonetheless, looking at the global pathways, although there seems to be large uncertainty on near-term behaviors, models tend to highly agree on the long-term phaseout timeline of conventional coal power generation at the global level – that is, by around 2040 for 1.5 °C and by around 2050 for 2 °C. It suggests that across these scenarios, China’s coal phaseout also needs to happen no later than these timelines, consistent with our results.

Moreover, different technology futures or electricity demand has little impact on coal generation pathways under deep decarbonization scenarios. For example, the comparison with the IPAC results illustrates that although different models have very different projections and interpretations about how China will achieve power system deep decarbonization (i.e., through different combinations of alternative technologies), the retirement pathways of conventional coal power generation to achieve the climate goals are consistent and robust (Supplementary Fig. 6a).

Moreover, low electricity demand only marginally delayed the coal power decline. In addition to the core scenario (low demand) used for plant-by-plant retirement, we also looked at a high energy demand scenario for each climate target. With higher energy demand to achieve the same emission pathways, power generation from conventional coal plants will need to decline faster (Supplementary Fig. 6b, c) to offset the increased emissions in other sectors, mainly buildings and industry (Supplementary Fig. 6d). This indicates that improved efficiency (as in the low demand scenario) can slightly slow down coal phaseout in the near term.

A number of variables, either collected or estimated at the unit level, are used in the calculation of metrics, including location, capacity, vintage year, combustion technology, application, heat rate, coal type, and project developer. To get a more up-to-date version, it is further modified with more recently built power plants during the months of February to May of 2019. The reference data of our update is according to the latest information published on the Beijixing power website1) that describes the data in more detail is provided in Supplementary Methods.

We developed the three-step retirement algorithm based on multi-criteria decision-making (MCDM) method2 emission rate, local air quality, and human health impact assessed with the population-weighted PM2.5 concentration level of a plant’s location, and water impact estimated with the water risk level of a plant’s location (see Supplementary Methods for the calculation of individual criteria).

In particular, the local air pollution and human health impact metric and the water impact metric characterize the overall environment in which the plant is operating, whereas the technical metrics capture the characteristics of individual plants. Other conditions equal, shutting down a coal plant operating in a highly polluted or water scarce environment leads to larger marginal benefits, and thus such a coal plant has a higher retirement priority than those located in an environment with less pollution and water scarcity. These environmental metrics have limitations in that they do not capture the exact air pollution impact from each coal plant. Our choice to use these metrics is partially related to data limitations on plant-level air pollution control technologies.

We use the environmental metrics to focus on the need for continuous air quality improvement in the long run. In recent years, China’s coal plants have significantly reduced air pollutant emissions through widely installed end-of-pipe emission controls. The implementation rates of SO2, NOx, and primary PM2.5 control technologies reached approximately 96, 93, and 100%, respectively, in 20183. Such long-term improvements require a different strategy – that is, an energy system transition from coal to renewables

Next, we aggregate the metric scores to each of the three dimensions by averaging individual metric scores of the given dimension. The dimension score of technical attributes, for example, is equal to the average of the metric scores of plant age, size, technology, and application and also has a value range from zero to one.

Lastly, we take the weighted mean of the three dimension scores as the combined score. The results presented in the main text are based on the equal weighted mean method to combine the three dimension scores. The retirement order of all plants is ranked according to this combined score. A lower score indicates a plant is ranked lower by the retirement order and should retire first.

$${\mathrm{Combined}}\;{\mathrm{score}} = (w_{{\mathrm{tech}}} * D_{{\mathrm{tech}}} + w_{{\mathrm{profit}}} * D_{{\mathrm{profit}}} + w_{{\mathrm{env}}} * D_{{\mathrm{env}}})/\mathop {\sum }\limits_{i = 3}^1 w_i$$

Power sector’s contribution to local air pollution tends to vary across regions, which may affect the health benefit gained by shutting down coal plants at different locations, and thus affect the retirement priority ranking. Therefore, we use two alternative metrics for local air pollution in the retirement algorithm as sensitivity analysis: percentage of SO2 or NOx emissions from the power sector at the plant’s location (see Supplementary Table 1). We find that provincial coal phaseout pathways are robust across different metrics used (Supplementary Fig. 11a, b). This suggests that although individual plants’ ranking may change with different air pollution metrics, the retirement time schedule consistent with the 1.5 °C or 2 °C climate target is not sensitive to this assumption.

Among all the provinces, Inner Mongolia tends to show a relatively larger change in the near-term pathways (Supplementary Fig. 11a, b). Under both the “power SO2” and the “power NOx” methods, coal plants located in Inner Mongolia retire slightly faster than the original “total PM2.5 concentration” approach, indicating that the power sector contributes to a larger share of the local air pollutant emissions in the region.

To investigate the uncertainty existing in our retirement algorithm, we perform a sensitivity analysis on the weighting methods to calculate the combined retirement score. First, we tested an “equal-weight” method. Instead of the two-step weighting method applied in the core analysis, we apply an equal weight for all the individual metrics to calculate the weighted average as the combined score. As a result, technical and environmental dimensions will have a larger weight than profitability due to more metrics included. These two weighting options tend to have marginal impact on the provincial coal retirement pathways (Supplementary Fig. 11c).

Second, we tested a “CHP-prioritized” method. Specifically, CHP plants located in northern provinces are given a higher score when rating application as part of technical criteria (see Supplementary Methods and Supplementary Table 2). Northern provinces here include Hebei, Shanxi, Inner Mongolia, Heilongjiang, Jilin, Liaoning, Shaanxi, Ningxia, Gansu, Qinghai, and Xinjiang. This weighting method highlights the important roles of CHP plants in heat generation in northwest China grid, north China grid, and Northeast China grid. Again, these two weighting options tend to have a marginal impact on the provincial coal retirement pathways (Supplementary Fig. 11d).

Level of retirement agreement between two different weighting methods is quantified using the number of coal power units that are agreed to retire by the given year based on both the methods. The overall retirement agreement level is high between the original weighting method and CHP prioritized method, as well as the equal-weighted method under 1.5 °C and 2 °C (Supplementary Fig. 12). The agreement also increases with time as well as the stringency of targets. However, near-term decision making is critical. In the next decade, about a third or half of the retired coal plants will change when different priorities are adopted.