EXCESS brings together 21 partners from eight European countries to showcase how nearly-zero energy buildings in four different European climate zones can be transformed into positive energy buildings (PEBs). Each of these partners brings in their unique insights and expertise into research, policy, industry, markets and innovation linked to energy efficiency in buildings, technologies, and sustainable communities.

We are talking to Florencio Manteca González, Director for the Energy Transition in Cities at the National Renewable Energy Centre for Spain (CENER) to discuss Positive Energy Buildings (PEBs) acceptance and integration on the Spanish energy and housing market, the city of the future and what is next for the PEB building in Spain.

To begin with, what technology solutions for the EXCESS PEB demo buildings are you currently working on at CENER?

At the National Renewable Energy Centre of Spain (CENER) we are developing and transferring mature technology solutions for the energy transition and decarbonisation of markets. As a public research institute, our job is to find solutions through applied research in the fields of wind energy, solar thermal and photovoltaic, bio-economy, energy transition in cities and green hydrogen. 

In the EXCESS project, we are responsible for the development of different energy concepts for the EXCESS PEBs in the four different European climate zones, as well as the implementation of technology in the Spanish EXCESS PEB demonstration building. Concretely, we are finishing the development of the predictive control algorithms model which will be installed in the demonstration building in Spain. This will optimise the energy efficiency of the building by taking advantage of energy flexibility possibilities. The model will, for example, optimise the management of the building equipment for specific conditions (regarding atmospheric, occupation or internal loads) that occur during the operation of the building. This optimisation requires an in-depth knowledge and modelling of the systems in place.

What is the motivation behind CENERs involvement in advancing PEB technology and solutions within EXCESS?

The decarbonisation of cities is one of the biggest challenges that we are facing today in Europe and we will have to meet it with a plenitude of solutions and strategies. We believe PEBs to be an impactful element in this mix of solutions.

However, for the time being the technological solutions available for achieving a plus-energy building standard in different climatic zones and conditions, are still more expensive than a conventional building. We will need to continue developing cost-effective solutions to transform the European building stock cost-effectively.

At CENER we want to enable this transformation. PEBs are hence a priority for our researchers at the CENER Energy Transition in Cities department and this is why being part of the EXCESS project is so important to us.

You mentioned your work on the EXCESS PEB building in Spain, what is the current status of the development site and what do you expect for the coming year?

The EXCESS demonstration building for Spain is an old palace building from the XVI century in Valladolid. It is currently being refurbished to become a residential positive energy building under the premise of safeguarding its historic elements and heritage. The works on the palace are still ongoing. This includes the inner layout and tappets. We are planning to deploy the energy HVAC systems and renewable energy components by July 2023. If all goes according to plan, we will be able to complete the transformation of the building by September 2023

How are the PEB ambitions and solution received by the actors on the ground according to your experience?

The integration of renewable energy in buildings is a long-standing issue in Spain. In fact, since 2006 it is mandatory to supply a percentage of the energy demand with renewable sources in each building.

As a result, there is now an increasing demand in the market for energy-efficient buildings and renewable supply.

In the last year, uncertainty regarding gas supply and the continued rise in energy prices due to the invasion of Ukraine has created a huge interest and demand on the market for integrating renewable energy systems in buildings, shared self-consumption systems and energy communities in Spain, including PEB standards for buildings.

From your point of view, what are the biggest obstacles for a larger take up of PEB solutions in Spain and in Europe?

There are currently many challenges and barriers still in place for achieving a broader proliferation of PEB solutions. On the one hand, there are important legislative constraints in Europe, including prohibitions and loopholes, which severely limit the interaction of building owners in the energy market. For this reason the possibilities of energy flexibility can often not be fully exploited yet.

Then, there is a cost barrier. Too often, the energy efficient solutions, as well as the renewable technologies come with a higher investment cost, even though the solutions are cost-effective in the long run. This is a big factor for why many people to still opt for a conventional building over building or buying a PEB. I am confident that with further research, this will change in the coming years.

Finally, I would say that we need training in the building sector, urban planners, architects, HVAC engineers, construction workers and guild to promote higher energy efficiency and integration of renewable energy systems.

What is your biggest surprise and take away from working with partners on PEB solutions across Europe in EXCESS?

Whereas, as a team of partners from all over Europe, we are all faced with the challenge of decarbonising urban areas and achieving climate neutrality in European cities by 2050, the local context and conditions are very different.

We are currently faced with not only different legislations and varying climatic conditions or availability of renewable resources, but also with different cultural and economic contexts. The optimal technological solutions are therefore simply not the same from one country or even from one region to another.

For example, in Southern Europe, there is less energy demand for heating and more potential for solar energy production than in Scandinavia, but at the same time, there is a much higher cooling demand. Meaning, while we are all in the same boat when it comes to the direction, I found it very inspiring to see the different solutions that have been found in each pilot to harness different local conditions for achieving the same objectives: to build a building that produces more energy than it consumes.

If you had one wish to facilitate your work on PEB solutions, what would it be?

Undoubtedly, a change of the legal barriers that exist in all EU countries when it comes to managing energy self-consumption and feeding electric surpluses back to the grid. For a technology centre like CENER, it is not the technical challenges that worry us. We are confident that we can solve them.

The biggest barriers we face at the moment are administrative and legal ones. It has been much more complicated for us to manage construction permits or to find a regulatory framework that allows us to commercialise surplus energy than to technically install a positive energy buildings.

Let us take a glimpse into the future: What do you expect our built environemnt to look like 30-40 years from now?

If we look at population projections in Europe, the number of people living in urban areas will increase even further in the next decades. At the same time, many cities and Europe as a whole, have committed themselves to achieve climate neutrality by 2050. I am hence imagining much smarter cities with an extended system of automatic and electrified services, including a fully electrified public transport system.  In fact, I am expecting most cities will be almost fully electrified, with local renewable energy generation facilities integrated throughout urban centres.

The smart systems and technologies that will manage these extensive social services and smart urban life that I am imagining are not yet existing, but we are working on it.

More information about CENER and Florencio Manteca:

CENER is a technology centre with worldwide recognised prestige, activity and experience. It develops applied research in renewable energies and provides technological support to companies and energy institutions in six areas: wind, solar thermal and photovoltaic energy, biomass, smart and energy efficient buildings and districts, and grid integration of energy. CENER has different infrastructures to test, validate and develop energy related technology, such as Wind Turbine Test Laboratory, Experimental Wind Farm, Biorefinery and Bioenergy Centre, ATENEA Microgrid and Laboratories.

Florencio Manteca is Director for the Energy Transition in Cities at the National Renewable Energy Centre for Spain passionate about Sustainable Architecture, Renewable Energy and Low Carbon Cities.