Online sources are debating the topic of district heating as an increasingly important means of generating cheap sustainable energy for future generations. What exactly is district heating and why might it help to create an interesting future for the UK and Europe?

What is district heating?

District heating or energy is a heat-generating system that is located and distributed centrally, satisfying residential and commercial heating needs such as hot water and space heating. The heat is often generated via fossil fuel plants, but increasingly these are being replaced by 'greener' methods, such as geothermal heaters, biomass boilers and solar arrays. Nuclear power is a more controversial method.

The benefits of district energy plants is that they have the ability to provide more efficient heating and better control of pollution when compared to local boilers. Research suggests that district heating, when used with combined heat and power, is the cheapest way to cut carbon emissions and produces the lowest carbon footprint. These types of power plants are being developed in Denmark as stores for renewable energies, such as those generated from the wind and sun.

Different types of district energy plants

There are different types of district heat systems and sometimes these are simply heat-only plants. Others are full power-and-heat combined plants, producing electricity as well as heat. These can be very efficient, with the more advanced facilities providing nearly 80% of heat efficiency. Such district heating plants are also being built in Ukraine, Hungary, Slovakia, Switzerland, Brazil and Sweden.

The substations will distribute the generated heat to the customer network via a series of insulated pumps, comprising of feed and return routes. These pipes are usually laid underground and the heat is usually distributed by water or steam. Steam is the less common method used, but it has the advantage of being available for industrial processing at higher temperatures. The heating network of pipes will then be connected to dwellings by heat substations. A system in Norway is currently operating successfully with this method, losing only 10% of thermal energy through its highly efficient distribution system.

Heat meters

Once the heat is within the customer's building, it is usually metered to encourage customers to use energy only when necessary. Many of the old communist-era district heat systems were neither efficient nor metered, prompting many people to open their windows as far as they would go when their buildings became too hot. Metering eliminates this issue and allows for consumer control.

The pros and cons

There are various advantages of district heating systems over individual heat systems. The former tends to be more efficient and the larger-sized combustion units have more advanced cleaning systems in their gas flues. They can often utilise heat outputs from industry for efficient energy 'recycling.' However, these systems do require long-term investment and government policy must focus on the long-term gains. The systems are also best suited for areas with high population densities, particularly those with apartment blocks.

Already in the UK, there are district heating workshops and towers in London's Pimlico and there is a large EnviroEnergy plant in Nottingham, which now heats over 4,600 homes and business premises. Scotland also has a range of district heat schemes and Southampton has a significant scheme.

This post was written on behalf of ENER-G, click here for more informative information on alternative renewable energy systems

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