Combined Heat & Power
For markets with district heating, the waste heat from the BTC plant can be used to provide usable heat energy for space heating and potable hot water while at the same time producing high efficiency power at almost twice the efficiency compared to traditional solutions. This is what Combined heat and power (CHP) plants do. The BTC plants have very high electrical efficiencies compared to the traditional CHP plant technology, the steam cycle, while at the same time providing a high total plant efficiency including heat energy.
More locally produced electricity
The great thing about CHP plants is that power is produced near consumption since district heating grids typically are very local, extending up to 50 km from the production plant for a larger city. In large grids, several plants are working together to provide heat to the grid. In such grids, different technologies and plants will have different operating conditions where waste-to-energy plants typically operate year-round, whereas (fossil) peak plants only operate maybe 500 hours/year or even less.
With the higher electrical efficiency of the BTC plant, the ratio between power and heat changes, in the industry referred to as the Alpha value. Typically, this ratio is 0.3, 30% power - 70% heat. In the BTC plant the ratio is ~1, meaning 50% power, 50% heat. Through this change in ratio, almost 3 times as much electricity can be produced from a given district heating grid. This increase in locally produced and flexible power reduces the need for transfer capacity and also stabilizes the local grid, enabling for even more transfer capacity in existing grids.
Flexible and plannable production
Biopower plants, like the BTC plants can plan production to meet the needs for power and heat. A typical BTC plant is expected to operate 50 - 60% of the time over a year, with some periods at part load, depending on local conditions. Primarily, it’s expected that the plant will operate during the cold half of the year but given recent market development, power-only operations during the warmer half of the year is also very likely for some periods of very high power prices.
Optimal for modern grids
The BTC plant is ideally adapted for modern district heating grids, sometimes called fourth generation, where temperatures are lower than older grids. The BTC plant has waste heat that can supply a district heating grid at temperatures of 75 – 78°C. This heat supply is generated by the flue gas condenser and is provided independently from the power generation cycle. For grids requiring higher temperatures, especially in winter, a complementary peak, biomass-fed, boiler, or high-COP heat pump, may be needed.
