ForTheDoers Blog

Heating the cities without burning

Tatu Kulla 13 November 2019, 17:06 EET

In the longer term, we can stop burning in energy production entirely. Four major elements are needed to achieve that.

Brick houses in a city

The transition away from fossil-based fuels has started and the pace is increasing. Currently, wind and solar are already mainstream in electricity production, and heat is increasingly being produced with bio-fuels, waste-derived fuel and gas.

Many heat producers in the Nordics have stated that they will stop burning coal within the coming years; Fortum, for example, has a solid plan to close down all its coal burning capacity in Espoo in 2025. Before that, security of supply must be ensured. In the longer term, we can stop burning entirely. How are we going to do that? The plan consists of four major elements:

  1. Recovery of waste heat
  2. Electrification
  3. Customer insight
  4. Digitalisation

Don’t waste heat – it can be recycled

Let’s start with waste heat. In most applications where electricity is being consumed, most of the electricity actually converts into heat. My laptop’s cooling fan is cycling on and off as I’m writing this post in order to move the heat produced by the processor and other components to the air outside the laptop’s casing. This heats up the office I’m sitting in and results in either a reduced need to heat up the office space or a need to even cool down the office. The warm air is typically cooled down by an air conditioner and the excess heat is blown outside the building.

In advanced systems, excess heat is already recovered using heat pumps and injected into the district heating network. One office building is a small heat source, but if you start thinking about activities where large amounts of electricity are being consumed, the number of possible heat sources becomes enormous. For example, data centres would be ideal heat sources, as they consume lots of electricity; they could actually sell the waste heat to the district heating network and in doing so could reduce their operating costs. Only the district heating network is able to recycle and redistribute that amount of thermal energy. If (and when) heat recovery becomes mainstream, the heat production topology would change from a few large, centralised production units to smaller, geographically scattered units.

Heat storages are 100 times cheaper than electric batteries

Extensive electrification is seen as the best way to decarbonise society. In many cases, using waste heat as heat actually electrifies heating. The technological and economic development of wind and solar power generation has been extremely fast, and today they are the cheapest forms of electricity production. However, both solar and wind are intermittent production forms, as their production depends on weather conditions.

Development of different electricity storage technologies, especially lithium-ion, has been rapid, but these technologies are still not economically feasible for storing a large amount of energy. And there are many challenges related to the raw materials needed for these technologies.  

Storing electricity as heat is actually 50 to 100 times more efficient than storing it in batteries. Basically, the water is heated and is stored in a hot water storage for a day, a week or even a season. Therefore, in the future energy system district heating networks and purpose-built heat storages can help the electricity system by storing excess electricity and using the stored heat to meet the heating demands of customers.

Digitalisation enables better living conditions

Speaking of customers, they will play a major role on the journey towards a fossil-free heating system. As in all energy-related issues, maintaining balance is key. By utilising customers’ demand flexibility, we could cut some of the system-level demand peaks, which are typically the most challenging to cover. This doesn’t mean that customers would have to live with cooler homes during cold periods – actually, the end user wouldn’t notice a thing. If smart sensors measuring temperature and humidity were installed in apartments or offices, the heating delivered would be just the right amount to maintain a consistent temperature and the quality of living would increase. And it would bring an energy savings, too!

We have now gone from centralised to decentralised, connected heating to electricity and taken customer demand flexibility into use. After all this, the system becomes far too complex to manage manually. We need digital tools and artificial intelligence. The future system produces lots of data through different measurements at the customer end, in the heat network, etc. In order to manage this, heat producers need to develop their ability to manage enormous amounts of data and turn that data into meaningful operational decisions that are timed just right.

For a heating company like Fortum, the change described above is fundamental, as we need to change from a vendor of energy into a service provider who ensures that customers receive exactly what they need. We cannot make this change alone; we need to do it together with our customers, our partners and society.

All in all, it is possible to move from fossil-fired to fossil-free heat production, as evidenced by our Espoo Clean Heat project. All the tools needed to make the change are actually already available. Now is just a matter of hard work, dedication and commitment!

Tatu Kulla

Head of System Optimisation and Fuel Management
Heating and Cooling
tatu [dot] kulla [at] fortum [dot] com

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