|Combined heat and power||Combined heat and power|
We have a tradition of combining power and heat production. By producing power and heat at the same time at DONG Energy’s power stations, we have achieved an efficiency of around 72 %. This makes our power stations cost-effective, and results in a high exploitation of the fuel’s energy content.
Combined heat and electricity at power stations
Exploits steam to produce district heating
Increased effecientcy by producing both electricity and heat at the same power station
Bioenergy & Thermal Power has a unique tradition of combining power and heat production. The surplus heat from power production is recycled in the district heating system, which supplies heating and hot water to Danish customers.
Exploitation of steam for heating
When the steam has released its energy to the turbine, which is used to produce power, it is used to heat cold district heating water in a heat exchanger. The district heating water is thus heated, and the steam cools and turns to water, which is then pumped back to the boiler where it is converted to high pressure steam. District heating water is heated to approx. 100-120°C, and is then distributed to heating customers via district heating pipes. Part of the district heating water is stored in storage tanks, which can be drawn upon as required, as heat consumption varies according to seasons and time of day.
Highly effective production
In general, increased net efficiency means less fuel consumption for the same output of energy. Combined heat and power generation improves the total net efficiency of our thermal generation assets by enabling us to utilize a substantially higher proportion of the energy content in the fuel we consume, relative to consumption in stand-alone power and heat generation, this fuel saving representing the CHP Advantage.
Taking into account the total energy generated and energy content in the fuel consumed, the average of the actual total net efficiency achieved from our thermal generation assets was approximately 65% in FY 2013, 66% in FY 2014 and 72% in FY 2015 (the average calculated as the ratio between the total energy generated and the energy content in the fuel consumed in total by all of our thermal generation assets).
DONG Energy owns nine central power stations accounting for the vast majority of DONG Energy's total electricity and heating production. In addition to this, we have a waste-fired power station, which also combines electricity and heating production. DONG Energy is the largest producer of district heating in Denmark and delivers 26% of the market's heating in 2014.