Improving efficiency, reducing operating costs and meeting environmental regulations will result in a retrofit and upgrade investment market to the tune of $532 billion at coal-fired power plants in the US and Europe by 2020, according to the McIlvaine Company’s utility tracking system.
Although natural gas is now fairly low cost, the Department of Energy predicts the US will burn more coal in 2035 than it does now, McIlvaine says. Coal consumption at European utilities is substantially higher this year since it’s cheaper than alternatives; McIlvaine says there is great incentive to burn coal cleanly and economically.
The market research firm says Europe is committed to coal, citing France’s contracts to upgrade three 600 MW coal-fired boilers and to extend the life for another 25 years, as well as Eastern Europe’s dependence on coal.
In both the US and Europe, the largest expenditures will be improvements in combustion efficiency, McIlvaine forecasts. The average US plant emits 30 percent more CO2 and uses 30 percent more coal than a new ultra-super critical power plant that has an efficiency of 45 percent to 48 percent, and consumes less coal than a traditional coal plant to produce the same amount of electricity, so it emits less CO2 per kilowatt generated. McIlvaine says upgrades will not be able to fully duplicate a new ultra-super critical plant, but they can improve efficiency by 10 percent or more.
Many European plants have already switched from volumetric to gravimetric feeders. A volumetric feeder discharges a volume of material as a function of time while a gravimetric feeder weighs material, so it’s more accurate when handling bulk solids whose density varies. Controlling the variation in fuel flow by itself can improve efficiency by several percent, and this can be enhanced by smart valves and pumps that increase performance and reduce maintenance costs.
The biggest expenditures will be in monitoring and automation. Monitoring the conditions at a number of specific points in the boiler and then varying fuel, the air flow through individual burners, will be one upgrade. The automation of the operation is necessary because of the complex trade-offs between efficiency and NOx emissions, McIlvaine says.
Neural networks that use empirical knowledge to optimize operations will be another important addition to the upgrades, the firm predicts, because the networks will operate better by replacing today’s sensors with smart sensors that digitally convey intelligence to the transmitter instead of just sending an analog signal.