Positive energy buildings: Demonstrators, replication guidelines and a policy map
Decentralising and democratising energy production – with citizens producing, managing and consuming their renewable energy – will be critical to Europe’s transition towards climate-neutral cities. Positive energy buildings (PEBs) and positive energy districts (PEDs) go further, with surplus production of renewable energy. The EU-funded EXCESS project set out to transform nearly-zero-energy buildings into PEBs, focusing on integrated solutions in the four main EU climatic zones represented by Austria, Belgium, Finland and Spain.
Seasonal energy storage solutions urgently needed
European building stock, climate conditions and energy requirements are highly diverse, requiring adaptable and modular technological solutions. EXCESS’s work highlighted the significant differences in market readiness of critical technologies. Conventional PEB technologies including photovoltaic (PV) technologies, batteries, heat pumps and insulation materials are market ready. Innovative PEB technologies like PV thermal (PVT) technologies, multifunctional energy-efficient façade systems and hybrid geothermal systems are close to commercialisation. However, “seasonal energy storage solutions that will be key for PEB are lagging,” explains Andreas Tuerk of JOANNEUM RESEARCH, project coordinator.
Beyond technologies, climate and building considerations
Energy storage is particularly important to achieve positive energy solutions, and even more so in northern climates. It was much more difficult to achieve a PEB in Finland due to its high heat demand and limited solar irradiation whereas it was easy in Spain. Building shape was the second most critical factor next to climate zone, with up to a few storeys and a large roof being best.
Regulatory, legal, financial and workforce barriers
Because PEB technologies are often more expensive than conventional technologies, integrated technology portfolios are needed to reduce the lifetime costs. For example, PVT can reduce the energy-related drilling costs of a geothermal heat pump. However, regulations such as those limiting drilling for heat pumps or fire protection rules were barriers in most EXCESS demos. Higher investment costs can be partially compensated by lower electricity costs but subsidies, grants and other support are needed. Regulatory frameworks for small-scale provision of flexibility services should be improved, unlocking additional revenue and energy savings. “ICT control systems combined with smart, incentivising/rewarding tools for end-users can contribute to energy savings of up to 10 %,” Tuerk explains. Finally, skilled labour, knowledge and manufacturing capabilities are needed to support PEB and PED technologies. For example, PVT is well-established in France but installers are difficult to find in Belgium and Finland. The construction sector needs training to implement new ICT solutions. Development of automated manufacturing technologies should accelerate renovation using prefabricated multifunction facades.
The way forward: commercialisation, replication and policy
Several technologies matured by EXCESS are heading to market: PVT in combination with geothermal heat pumps in the Nordics; high efficiency heat pumps in central and eastern Europe; and a multifunctional façade in Austria. The EXCESS webpage contains insights on replicating EXCESS PEB technologies and policy recommendations. Tuerk summarises: “Whether individual PEB technologies or portfolios, these must be mainstreamed into urban planning and urban energy and climate plans. This will need to be complemented by mass production and automation of installation for significant cost reductions, and mitigation of legal and regulatory constraints. Addressing these, the EU can achieve a much higher contribution of renewable energy – and an increasing number of PEBs and PEDs – by 2030.”
Keywords
EXCESS, energy, PEB, PED, heat pumps, PVT, energy storage, geothermal, positive energy buildings, PV, positive energy districts