The buildings sector has an important potential for the development of Renewable Energy Applications (RES), according to the relevant roadmap (REmsp) that was recently (2016) presented in a report published by the International Renewable Energy Agency (IRENA), with data from 40 participating countries around the world. As clearly stated, buildings present the best opportunity for the increase of RES use, mainly as a result of the extension of the use of modern biomass applications and the increased consumption of electrical energy, the production of which is increasingly based on RES.
In more detail, IRENA recognises the important role of the buildings sector in the global Total Final Energy Consumption (TFEC), with a total contribution of around one third, 33% out of which is for heating, 30% for cooking, 20% of warm water and 2% for cooling, the latter projected to reach 6% by 2030. RES contribution to covering the energy demand was about 35% in 2010, the highest proportion of which, around 60%, attributed to “conventional forms” referring to the use of bioenergy for heating and cooking, mainly in countries across Africa and Latin America. The global RES consumption in buildings in 2010 was about 40EJ (40 billions billions Joule), out of which, 25EJ originated from solid biofuels such as wood for traditional usages of heating and cooking and around 15EJ originated from “modern” RES such as biomass, liquid/solid biofuels, solar thermal, geothermal energy, RES for electricity production, district heating and usage of heat surplus or excess of heat etc. This figure could be tripled to over 50EJ by the implementation of initiatives for further deployment of RES (“RE Options”), specifically for each country on top of current measures, referred to as the “reference case”, as seen in Figure 1 analysing the distribution of RES in energy use in the buildings sector across the world (source: IRENA REmap, p. 77) presenting 3 cases:
- The status recorded in 2010,
- The projection for 2030, according to the current planned activities for RES development (Reference Case) and
- The projection for 2030 with the adoption of further practices (specific for each country) for RES development (Remap 2030):
Figure 1: RES use in the buildings sector, projections for the year 2030
The report also notes that energy policies usually focus on the production of electrical energy, whereas heating does not draw so much attention. In particular, only 50 countries have developed specific policies for promoting the use of RES heating, whereas 120 countries have developed similar plans for electrical energy that include, for example, subsidies, feed-in tariffs, tax reductions or exemptions, loans with low-interest rates, CO2 taxes, and guarantees, etc. However, as the report continues there exist opportunities for the development of RES heating applications in buildings, depending on the location, the quality and the quantity of energy sources. For example, alternatives such as the use of bioenergy (biomass, biogas) and solar thermal can be cost competitive with the other sources, under suitable conditions.
Furthermore, the report recognises the catalytic role of energy efficiency and its synergetic role with the use of RES. The idea of energy efficiency is directly related to the supply of primary energy (fuel), e.g. oil or coal consumption for electrical energy production. The report notes that in 2010, the share of RES in the primary energy mixture across the world was around 10%, with the potential to increase to 25% by 2030. However, by improving energy efficiency, this share can be increased to 30%. Therefore, the report stresses out that it is vital to focus both on energy efficiency and the development of RES, in order for the latter to have greater penetration levels.
More specifically for the buildings sector, the report notes that significant energy gains can be achieved, especially in new buildings. The European Union Directive for nearly Zero Energy Buildings (nZEB) that will be in full force by the end of the decade, can also significantly contribute to the enhancement of energy efficiency.
The report, however, notes that the gains from increasing energy efficiency will not be automatically realised. In particular, the transition towards more energy efficient practices has progressed significantly in the electrical energy production stations, but it is left behind in the buildings sector, in the industry, and in transport. Notably, for Europe, the gains from nZEB buildings will most probably be confined to new (under construction) buildings and to a rather small number of buildings that undergo a process of renovation. However, worldwide, the situation can be different in countries that present higher rates of buildings constructions, that can apply advanced forms of architecture more easily and the adoption of practices or standards relevant to the EU nZEB requirements can lead to a significant increase of energy efficiency.
Finally, as regards the development of synergies between energy efficiency and RES, the report suggests the adoption of strict practices for energy efficiency in buildings and the increase of the rates of reconstruction/renovation of existing buildings that will utilise RES for heating and cooling. Furthermore, it suggests focusing on RES use for the management of energy demand when the targets of efficiency are met, together with the use of bioenergy, thermal solar systems and heat pumps.
Written by Dr. Fotios Stergiopoulos
Assistant Professor at the Department of Automation Engineering
Technological Education Institute of Thessaloniki