Old coal-fired power plants and new technologies

The United States now has the oldest coal-fired thermal power plants, whose average age will pass the 50-year mark next year. The US also operates about 92 nuclear reactors, with an average age of 42 years, making them the third oldest in the world after Switzerland and Belgium, where reactor ages average 46.3 and 42.3 years respectively. Most of the nuclear plants now in service in the US were built between the 1960s and the 1970s. These factors make the US energy infrastructure the oldest in the world. At present, however, the United States is focusing on developing thermal power plants that use gas as their primary energy, building out gas infrastructure and replacing old coal-fired plants with gas-fired ones.

Those coal plants were written down long ago and generate cash flow for the companies that own them, while creating environmental problems, since the technology of smoking units developed in the 1950s is technically obsolete. Elsewhere in the world, new coal-fired plants are appearing with units built to ultra-supercritical parameters, which noticeably improve the environmental performance of coal plants and the efficiency of coal as a primary energy source. But the US has taken a different path: it does not modernise its coal plants but closes them, shifting its power sector mainly to gas.

Some countries have already begun to use the new technologies in building and modernising coal-fired plants. In the UAE, generously endowed with oil, the first unit of a coal-fired power plant consisting of four 600 MW units has been commissioned. Four 600 MW units are equivalent to the two units of the Belarusian nuclear power plant, with a combined capacity of 2,400 (2×1,200) MW. The UAE coal plant uses units operating at ultra-supercritical parameters. According to experts, such a capacity of 600 MW can be achieved only with modern technology. The pioneers of these technologies were, in fact, the United States in 1949.

The point is that inside the boiler of a coal plant running at ultra-critical parameters, the operating temperature reaches well beyond 500 degrees. According to the latest open-source reports, China has achieved a coolant operating temperature of 800–850 degrees in its ultra-supercritical boilers. Whereas ultra-critical coal boilers reached an efficiency of 35%, ultra-supercritical boilers already achieve 45% and above. Where an ordinary coal-fired plant needs about 450 grams of coal to produce 1 kWh of electricity, an ultra-supercritical plant needs 230–240 grams per kWh. That means halving emissions of flue gases and ash. The use of filters and closed-loop water technology raises the efficiency of these new coal plants further still.

Compared with a gas-fired plant, a coal plant does not require LNG infrastructure, gas pipelines or underground gas storage, which makes the cost of the energy infrastructure considerably lower. For this reason it seems to me that coal will not disappear and will continue to play a very important role in the energy systems of many countries. The money simply has to be invested in developing new technologies and boilers in this field, all the more so because there is plenty of coal in the world, in practically every country, and coal makes energy substantially cheaper, alongside other branches of the energy sector.