At a workshop set to take place on 4 and 5 April in Graz, Austria, the IEA Solar Heating and Cooling Programme will launch a new research platform about Efficient Solar District Heating Systems, also called Task 68. This three-year programme will focus on medium-high temperature feed-in and digitalisation. Regarding the latter, the task members will take an especially close look at advanced control strategies, automated monitoring and open data, with the aim of exchanging best practice examples. For the first time, a solar heat technology provider will lead the knowledge-sharing activities.

“We will have a very strong focus on a systems approach. We would like to work on efficient hybrid solutions that use solar energy combined with other technologies to provide the supply temperatures required by a heat network,” explained Viktor Unterberger, who will chair Task 68 and is a senior researcher on Automation and Control at the Austrian BEST – Bioenergy and Sustainable Technologies centre of excellence.

Unterberger is being supported in his efforts by experienced IEA SHC solar heat strategists: Sabine Putz, of SOLID Solar Energy Systems, Austria, and Magdalena Berberich, of Solites, Germany, will both be subgroup leaders. Both were also members of previous Task 55 on Large Solar District Heating and Cooling Systems. A new subgroup leader will be Joakim Byström, of Swedish company Absolicon. For the first time, a technology provider will head the dissemination activities within an IEA SHC task. This will bring a new level of quality to outreach efforts, especially because of Absolicon’s wealth of experience in marketing and lobbying.

Stop burning wood in summer

One of the things that Absolicon has been campaigning for in Sweden is an SDH support scheme. The country in northern Europe has already had a fairly green district heating sector, with wood meeting more than half of all district heating needs nationally. But now, Sweden has a supply chain problem when it comes to local, sustainable biomass, as the country also wants to replace transportation fuel and high-temperature heat sources in industry with biomass-based energy carries.

Absolicon’s slogan “Stop burning wood in summer” has therefore been well received by policymakers. “The Green Party have put our call for a 50 % subsidy scheme for large solar district heating plants high on their agenda,” said Byström. “We are now pointing to the example of a raised budget for large-scale solar heat plants in Austria while also calling for financial support for feasibility studies.”

Biomass and solar for efficient district heating

Of course, Unterberger knows that SDH marketing slogans need to be adapted to different national contexts. In countries where biomass energy is not used as widely as in Sweden, biomass boilers and solar could be a suitable combination for providing green heat. One crucial argument for the promotion of solar district heating could be a high dependency on gas imports from geopolitically critical countries, such as Russia and Algeria.

Infocharts in general play a key role in Absolicon’s communications strategy. The company has created a number of easily accessible materials to explain the benefits and features of solar district heating to newcomers:

• District heating – History and future. 1-minute animation: https://vimeo.com/344270605
• Högslätten 2023 – Groundbreaking ceremony. 2-minute event video: https://vimeo.com/475839779
• Some like it hot: High-Temperature Solar Heat. Presentation held during an Austria Solar webinar and recorded on YouTube: https://www.youtube.com/watch?v=xXz0V8KBZHA

To learn more about how to join Efficient Solar District Heating Systems, do not hesitate to contact Viktor Unterberger at viktor.unterberger@best-research.eu.

Source and full article: www.solarthermalworld.org
Picture: Absolicon Solar Collector

The interest in solar district heating has increased significantly in Serbia since the European Bank for Reconstruction and Development (EBRD) started to finance prefeasibility studies for SDH plants in January 2019. Furthermore, Serbia adopted a Renewable Energy Law in April 2021 which includes an ambitious mechanism to support the implementation of renewable heating and cooling capacity.

The Northern Serbian city of Novi Sad (see photo) is one of the cities with a rather modern district heating system and a committed municipal council which is pushing the planning for a multi-MW solar heat plant. In this interview, Bojan Bogdanovic, Principal Fund Manager of the Renewable District Energy in the Western Balkans (ReDEWeB) programme, tells lessons that have been learned from three years of promoting solar district heating in the Western Balkan countries.

What is the current status of the planning process for SDH in Novi Sad?
Bogdanovic: In September 2021, the municipality accepted the prefeasibility study’s recommendations and decided to proceed and conduct a feasibility study together with the EBRD. The solar heat solution currently being discussed should be of more than 65,000 m² and have seasonal storage. This decision has been announced already via social media and we are waiting to receive the formal request for cooperation from the municipality. The city on the Danube has a rather modern district heating grid, which is very suitable for the feed-in of solar heat.

What are the convincing arguments for solar heat as an option to make the example central heat supply system in Novi Sad greener?
Bogdanovic: One of the major advantages are the zero local emissions of solar heat plants, considering that most cities in the Western Balkans have an air quality problem and therefore biomass plants are not always seen as an ideal solution for greening the district heating grid. Another important advantage is the stable and predictable heat prices throughout the lifetime of the facility, enabling the municipal utility to manage the system in an economically efficient way in the short, medium and long-term.

How good are the conditions for solar district heating in the Western Balkan countries?
Bogdanovic: The Western Balkans is one of the southernmost European regions with significant solar radiation and large district energy systems. Some of them have a high degree of modernization and digitalization, achieving operating parameters that are very suitable for solar. The average fluid temperatures in the return line are often below 50 °C because of efficient temperature regulation in the buildings, good hydraulic balancing and an increasing percentage of renovated buildings.

Project development times for solar district heating are generally long. What does your experience in the Western Balkans indicate?
Bogdanovic: Five years usually pass between the initial discussions and the start of the ground work. That´s why it is great news that the donors from the Austrian and Swiss governments have extended the ReDEWeB programme for two more years until December 2024.

What role does the distance between the collector field and the feed-in point play when searching for land? 
Bogdanovic: The distance between the land dedicated for the solar collector field and the feed-in point in the existing heat network, which needs to have a large enough dimension, or the heating centre is important for the feasibility of the project. The larger the scale of the project and the amount of heat generated, the longer a justifiable connection pipeline can be. Heat losses are not the key issue here but the CAPEX that needs to be invested in constructing the connection pipeline.

What do you expect from the new Renewable Energy Law in Serbia?
Bogdanovic: The law is a great step forward for SDH in Serbia. It stipulates that the government must establish a support mechanism to cover a certain share of the investment costs of renewable heating and cooling projects. What is important is that the law guaranties that the district energy utilities must purchase surplus heat from both private and public operators of renewable heat plants. The Ministry of Mining and Energy is currently drafting all the sub-laws necessary for the full implementation of the bill and it is expected that this process will be complete in early 2022.

Organisations mentioned in the interview:
https://www.ebrd.com/home
http://www.pancevo.rs/en/
http://www.grejanje-pancevo.co.rs/
http://www.novisad.rs/

Source and full article: www.solarthermalworld.org

The Spanish solar district heating market is still in its infancy. Among the 500 district heating networks in operation across the country totalling more than 1.6 GW_th only seven use solar heat, according to the Association of District Heating and Cooling Companies (ADHAC).

Project developers report that there are barriers relating to unclear urban construction regulations when planning solar district heating plants. The good news, however, is that solar district heating is one of the eligible technologies within the new national grant scheme PREE, which has a budget of EUR 400 million until 2023.

In Spain, despite much more abundant solar resources, this technology is still in its infancy. According to Miguel Angel Armesto, ADHAC President, only 1.5 % of the district heating and cooling grids include solar technology. “Solar thermal requires more space and there is not currently a direct incentive for solar district heating,” explained Armesto.

According to Pascual Polo, President of the solar thermal association ASIT, “Today, the potential for district heating in Spain is underestimated and limited in areas with natural gas networks. Solar district heating is an innovative and promising solution that can be more cost-effective than gas district heating.”

Urban construction regulations thwart SDH

In Spain there have already been some promising SDH projects planned, for example in 2018 the Spanish city Alcalá de Henares announced their plan to build a renewable district heating grid for 12,000 inhabitants. However, according to Teodoro Lopez, head of DH Ecoenergías, the former promoter of the Alcalá project: “There is a lack of clarity in the urban installation rules. In Spain, we do not have a specific framework that allows district heating and, depending on the council, this is a disadvantage against other technologies.

However, he seems to be positive about the future. “We are already installing a heat network in Palencia town and expect to start two other new grids in 2022 in Castille Leon” reported López.

EUR 400 million available

According to Polo, “renewable heat is undervalued in terms of its potential within the political and social discourse.” The head of ASIT believes that it will be very difficult to achieve a renewable share of 42 % in energy end-use by 2030, up from 17 % today, unless the use of renewable heat and district heating is boosted. The 42 % target is part of the National Integrated Energy and Climate Plan in Spain and is coordinated with European targets.

ADHAC´s President Armesto is optimistic that the new Energy and Efficiency Building Rehabilitation Programme (PREE) will support investments in district heating and solar district heating technology. The programme provides EUR 400 million of direct subsidies for new solar water heaters, biomass boilers, and heat pumps until 3^rd December 2023.

Websites of organisations mentioned in this news article:
www.adhac.es
www.asit-solar.com

Programme For Building Rehabilitation (PREE) can be found here.

Source and full article: www.solarthermalworld.org

There is a lack of land available in Germany for solar district heating systems due to the complexity of the land-use plan procedure. Bene Müller, Co-Director for Sales and Marketing at solarcomplex AG in southern Germany thinks that renewable district heating plants should be privileged according to paragraph 35 of the German Building Regulations, otherwise decarbonisation of the heating sector will not be possible.

Mr Bühler of the company Ritter XL said in an interview: “The German solar local heating market could be larger if sufficient land area was available”. Do you agree with him?
Müller: Yes, certainly. But fundamentally, enough land exists, it is just not easily available. The land for large solar heat projects has to be found right next to built-up areas. Agricultural land already competes with building land. In addition, solar district heating plants or infrastructure for regenerative heat generation in general are generally not privileged.

What would privileging mean and how could it be realised?
Müller: Paragraph 35 of the Building Regulations lists the types of project that can be privileged for planning and realisation on the edges of towns and communities. All building projects for the general supply of electricity are covered in these paragraphs. Wind power has also been included since 1997.
Here, federal policy makers are called upon to include general regenerative heat supply systems. For planners this would mean that planning permission is still required but no land-use plan procedure would be necessary before this. This hurdle certainly needs to be abolished.

What tasks are planners faced with in a land-use plan procedure?
Müller: The land-use plan procedure is very complex. It includes glare analysis reports, environmental aspects and the tedious assessment of alternatives. The latter is particularly obstructive because one can be happy to have found a suitable site at all. Having to prove that the site is better than others, even though these are purely fictitious, is an unnecessary hurdle. If district heating systems are to become the norm, the authorisation procedures need to be simplified.

Have you also experienced these difficulties in finding suitable land areas for wind turbines or PV?
Müller: Yes, there are also difficulties there, but the situation is different because with photovoltaics and wind turbines there is more freedom in selecting the location. A solar collector field always has to be constructed near to the heating network in order to minimize the losses in the connecting pipework.

Despite these planning hurdles, solarcomplex now operates 18 CO2-optimized heating networks in Germany. What is your recipe for success?
Müller: We now have many reference projects, so word has got around among mayors and local councillors. We often get a follow-up project from a nearby town when the heating network in the neighbouring community is in successful operation. However, the economic arguments are also important. We don’t make an extra charge for the building costs, which means that any heating customer can be connected to the heating network free of charge, and we offer competitive prices for the heat.

How do you achieve inexpensive heat prices despite the high initial investment costs?
Müller: Mostly we use waste heat from biogas plants, which we get for nothing from the farmers. The operators of the biogas plants receive a higher cogeneration bonus if the waste heat is utilised. In networks without any waste-heat potential we have constructed solar thermal plants, which also provide heat at a stable price of 2.5 EUR-ct/kWh, which is still very cheap. One should not forget that around half of the cost of the heat is dependent on the capital costs for the high investment in the new heating network. For each local heating network several million EUR are buried in the ground!

So what exactly is your business model?
Müller: We plan, build and operate a heating network in the streets of a community, with which we conclude a concession contract as a basis. Then we supply as many buildings as possible, including public once, with renewable heat. Nobody is obliged to connect to the system, we simply need to be economically attractive. Of course, we conclude heat supply contracts with as many customers as possible, before we start the construction work.

The interview was conducted by Bärbel Epp.

Source and full article: www.solarthermalworld.org

Picture: Solarcomplex