The European Union has mandated that greenhouse gas emissions over the next 38 years be cut by 80% from 1990 levels. That goal puts significant pressure on many sectors – transportation, utilities, urban planners, and builders, among others – to get their carbon-reduction act together soon. But the building industry, which is cited as a major source of emissions, will have to be especially agile in addressing energy efficiency if the EU is going to meet its target, a recent analysis points out.

By 2050, greenhouse gas emissions of the EU’s building stock will have to be 88% to 91% below 1990s levels, according to a study by the Brussels-based Buildings Performance Institute Europe (BPIE), titled “Principles for Nearly Zero-Energy Buildings: Paving the Way for Effective Implementation of Policy Requirements.”

The document driving these policy requirements is the EU’s Energy Performance of Buildings Directive (EPBD), which imposes what it calls a “nearly zero-energy building,” or nZEB, standard on all new public buildings beginning in 2019 and on all buildings (including homes) beginning in 2021. The EU is leaving it up to member states to draw up nZEB regulations suitable for their climate and other regional conditions, but the directive does define, in general terms, an nZEB as a “building that has a very high energy performance…. The nearly zero or very low amount of energy required should to a very significant extent be covered by energy from renewable sources, including renewable energy produced onsite or nearby.”

Balancing efficiency and renewables

The BPIE analysis is intended to highlight practical approaches states can take as the EU develops a more-specific definition for nZEBs. BPIE also looks at key features of existing nZEBs and offers technical solutions that stakeholders can apply as they try to shape their nZEB markets. Member states have until the end of next year to formalize their nZEB definitions, regulations, and carbon-reduction targets, which they’ll then submit to the European Commission.

One issue that will come into play in designing and building each project: how to determine the optimal balance between energy efficiency and renewable energy – a balance that will be struck in part, BPIE notes, by weighing climate-influenced energy demand, financing options, and the performance of existing low-energy buildings. BPIE also notes that while EU members may now have different ways of calculating building performance, the EU will have to agree on a single calculation method.

Given the EU’s management of its financial tribulations lately, it will be interesting to see how quickly member states can come up with a coherent and aggressive nZEB definition.