Stockholm has used district heating and cooling in such a way that heat waste has been reduced to almost nothing.

Nordic countries have relegated fuel poverty to the history books by setting legal minimum standards for heating and giving house-owners a strong incentive to invest in refurbishment, says the mayor of the Swedish capital.

Karin Wanngård has been mayor of Stockholm since 2014. She responded in writing to questions from EURACTIV’s publisher and editor, Frédéric Simon:

Heating and, to a lesser extent, cooling currently account for half of the EU’s annual energy consumption. What can European cities do to encourage a switch to cleaner technologies?
As a first step cities can start using sustainable biomass and waste that can no longer be recycled in the existing coal-fired power plants. Also, in many places today 60-70% energy used in electricity production is lost. By localising heat-demanding factories in the vicinity of the power plant this can be lowered considerably as they can use the excess heat.

If existing district heating grids are updated and expanded to modern smart grids, waste heat streams from industries or cooling of computer server halls and grocery stores can also be used for heating, resulting in even less energy waste.

The price of solar panels has gone down tremendously over the years. Companies like Tesla are now bringing solar tiles to consumers for a price they claim is competitive. Does the future of heating lie in solar?
Since the demand for heat is at its peak when solar panels don’t deliver, i.e. during nights and in winter time, using solar panels alone would need extensive investments in seasonal storing capacity. This would also mean large amounts of the energy being lost in the transformation process and in order to use this waste heat you would still need a district heating grid.

One smart solution is a combination of heat and power plants, using renewable fuels and waste, producing heat and also electricity to balance the periodic electricity production from solar and wind, together with a district heating grid to move waste heat from excess areas to where it is needed.

Biomass is still widely used in some countries but its use can be controversial. Paris for instance recently banned wood for heating to address air pollution issues. So does biomass still have a place in people’s homes?
Sustainable biomass is a crucial part of the fossil-free energy system. Together with waste heat this is one of the few available alternatives for heating Europe and it is a key component for Stockholm to reach the goal of being free of fossil fuels in 2040.

The problem for air quality is not biomass but boilers without cleaning. Air quality will suffer regardless if you burn biomass, coal, oil or natural gas in boilers without cleaning. Stockholm has substituted about 100,000 oil and coal chimneys without cleaning, with less than 10 big chimneys, burning biomass and waste, using state-of-the art exhaust cleaning and continuous monitoring of emissions. This has reduced air pollution substantially. The air quality in Stockholm is 100 times better than before and simultaneously about 1,000 fuel delivery trucks (10 % of the trucks) are no longer needed in our streets.

Substituting fossil fuels with biomass and waste energy, together with a high storage of carbon in growing forest, gives both a storm- and fireproof carbon storage and extensive replacement of fossil fuels. This is an everlasting method with far better climate performance, than the one-off method of letting the forest be unused until it stops storing carbon and becomes very vulnerable to storms and wildfires.

District heating systems are often cited as an example of efficient heating systems for cities. They are now commonplace in Nordic countries and were widely installed in Eastern Europe during the communist days. But they also require heavy infrastructure investments. Is this a technology of the past or of the future?
The potential in district heating is far from fully exploited. It is a climate-efficient way to balance periodic electricity from wind and solar, to move waste heat to where it is needed and to use waste that can no longer be recycled. In addition, it’s also preventing harmful substances from spreading in the environment.

Stockholm is now combining cooling needs for computer server halls and grocery stores with heating needs in residential areas, thus reducing heat waste to almost nothing. Seasonal heat storage is developing, for example by using solar panels and temporary excess heat, to heat water and store it underground for winter use. Smart grids and increasingly efficient heat pumps will offer many new applications and possibilities to utilise also minor waste heat sources. For example, we’re seeing development of washers and dryers using the heat directly from the district heating grid, thus avoiding transformation losses to and from electricity.

Subsidies for oil and gas still prevail across the EU, mostly to help the poorest households. How can Europe cut its addiction to fossil fuel subsidies, without hurting the needy?
The Nordic way has been to include heating in the rent and set legal minimum heat standards. This gives a strong incentive to the house-owner to invest in energy-efficiency refurbishment such as increased insulation and energy-efficient windows. This has resulted in Nordic houses being far more energy-efficient than in most other parts of Europe, especially if you consider our much colder climate.

A system which, in contrast, allocates the energy bill to the tenant – which has no competence to do these measures – instead risks causing fuel poverty. Fuel poverty is non-existent in Nordic countries.

The Commission’s proposed “clean energy for all” package includes new requirements for renewables and energy efficiency in buildings. What are cities’ demands when it comes to promoting renewables in heating and cooling?
Cities play a crucial role triggering energy transition and we support the European Commission’s efforts towards a more sustainable and energy-efficient EU.

However, certain parts of the proposed energy package contain a level of detail that can be counterproductive to the development towards a fossil-free Europe. For example, a classification that allows houses with energy produced on the very building (i.e. solar) to be less energy-efficient than if they use district heating, (thus also making it difficult to use waste heat streams), or forcing all house-owners to install individual heat metering and billing, thus taking away all incentives to implement energy-efficient measures at building level.

In addition, easily achievable changes such as quickly switching to renewable fuels in coal-fired power plants and using the enormous waste heat potential these plants represent, is almost entirely overlooked in the proposal. Cities that have done this have managed to lower their energy bill substantially and increase their energy security to 100 %. Developing and utilising smaller district heating grids can be an important first step in the right direction.

Source: Euractiv