dcsimg Optimising energy production - Ramboll Group

Optimising energy production

When the wind doesn’t blow and the sun doesn’t shine, we need an alternative but still effective and environmentally friendly way to produce energy. Energy optimisation of heat and power plants provides balance to the energy system and represents a reliable alternative to wind and solar energy - so reliable that it can become an efficient frontrunner in the conversion to sustainable energy production.


Currently though, 85 pct. of the world’s energy consumption comes from fossil-fuelled power plants. Heat and power plants are facing increasing challenges from the need to reduce their environmental footprint, and the global challenge is to ensure that new and existing power plants are as energy efficient as possible. At the same time, the energy market is characterised by a strong competition on energy prices, and the price fluctuations on fuel constantly change the state of the market.

Ramboll has gained extensive experience within power generation based on more than 25 years innovative use of biomass to generate heat and power in Denmark.

Improving energy efficiency

One solution is to optimise our energy production through know-how, practical experience and technology. In the Nordic countries, we see a move in the direction of existing coal-fired power plants being subject to optimisation, improving the plants’ efficiency rate significantly:

- The average power plant has an efficiency rate of below 40 % whereas the Avedore Power Station in Copenhagen provides 94 % efficiency. The same goes for Nordjylland Power Station near Aalborg that offers the world’s highest coal fuel efficiency rate due to high pressures, extreme heat and advanced processes. Such efficiency is pioneering and unique, and both plants are designed using field-proven technology, says Mogens Skov, Global Director at Ramboll Energy Power.

Bioconversion and lifetime extension is a time and cost saver

Another promising approach is to revive existing coal-fired power stations by optimising the energy production, converting them to the use of biomass and giving them 15-25 years of additional operation. An example is the extensive refurbishment of Studstrup Power Station near Aarhus where a conversion to 100 pct. biofuel is a prerequisite for the life extension.

- Besides a bioconversion, you analyse the existing plant and go through all pressurised components that are subject to wear and tear. These parts have a certain lifespan and need to be replaced in order to keep the plant running efficiently, says Mogens Skov.

A lifetime extension also saves you time and costs. In Europe, establishing a new thermal power plant typically costs about EUR 700 million. Modernising and refurbishing an existing plant costs just under EUR 150 million. Moreover, an existing plant takes about 1-2 years to refurbish whereas a new plant takes four to five years to construct.

Fuel flexibility

Markets are getting increasingly competitive and businesses are exposed to an ever more volatile political and regulatory environment, calling for highly efficient, innovative and flexible solutions.

The flexibility stresses the importance of a plant’s capability to swiftly change between the current politically and economically accessible fuels, be it coal, natural gas, oil, straw or wood pellets, in order to simultaneously generate heat and electricity.

- The changing energy market makes it vital for power plants to run efficiently on different biofuels. A plant’s flexibility and a multi-fuel design, where fossil fuels are used in a combination with renewable fuels in full flexible ratios, constitute a tried-and-tested effective way for Ramboll to optimise energy production and minimise the environmental impact, says Mogens Skov.

Holistic solutions

When seeking to optimise energy solutions, taking a holistic approach where social, environmental and economic perspectives are recognised in combined solutions, brings forth the most effective results. Besides converting a plant from running on fossil fuel to biofuel resulting in low CO2-emissions, an optimisation of the plant’s district energy supply system makes it possible to produce heat and electricity adjustably for the local district heat network instead of discharging the heat to the environment.

Again, Avedøre Power Station is a good example of a fully integrated 820MW high efficiency thermal power plant, supplying district heating and cooling to the capital of Denmark alongside producing electricity.

Great potential for cooling

Hand in hand with district heating, district cooling systems can be an integral part of a holistic energy optimisation solution through providing cooling to buildings together with chilled water for comfort and process cooling.

Today, district cooling is growing in the Nordic countries but unexploited in other obvious locations such as the Middle East where the potential is huge and the power plants energy economy could be improved enormously. In the Middle Eastern region, the plants’ 40 % energy production supplies houses with electricity but instead of discharging the remaining 60 %, a district cooling system could provide cooling to those houses as well; a service that is continuously sought after since Middle Eastern summer allows temperatures to rise well above 45°C.

- Implementing district cooling and optimising energy production in the Middle East seems like a win-win solution but still, district cooling is entirely unused in most of these countries as the solutions are untraditional, time consuming and technically challenging. However, it would reduce the vast quantity of energy currently being discharged and reduce  the long-term environmental and financial footprint of energy production, says Mogens Skov.

Read about Ramboll’s work with district energy.

A question of ambition

Since the oil crises of the 1970s, the Nordic energy industry has been refining technologies to ensure a diverse, sustainable energy supply. From oil to coal, from coal to natural gas and from gas to biomass; the Nordic plants using wood pellets are a source of inspiration.

Other countries have yet to set a similar level of ambition but plant optimisations and bioconversion schemes are on their way in countries such as the UK and Holland. The global challenge is to produce solutions that counter the effects of climate change and resource depletion and stand the test of time.

Read about Ramboll’s work with Thermal Power.


Mogens Skov
Mogens Skov
Director of Global Power Division
T+45 5161 3390