The H2 Vector, Hydrogen for Residential Use
Below is my article, originally published in the magazine TuttoGreen (2nd edition, July 2022), available here (in Italian).
The H2 Vector: Hydrogen for Residential Use Even in construction, technology is increasingly turning “green.” An nZEB-type residential building will use the H2 vector (the hydrogen molecule) to store energy during the summer season, which will be needed for its energy requirements during the winter season, respecting an energy “consumption smoothing.” A dream that becomes reality!
Buildings that are increasingly environmentally friendly Energy crisis and climate change? For several decades, we have been striving to build in a more respectful and conscious manner, paying attention to energy efficiency. Civil engineering has made significant progress in this regard, leading to the creation of standards defined as nZEB (nearly Zero Energy Building), i.e., buildings with high energy efficiency. In fact, building operations are responsible for 36% of global emissions. For these and other reasons, saving energy in the construction sector is considered one of the primary goals for more sustainable development.
In the last 10 years, some engineering companies (the data here was obtained from System Evergreen AG – Lugano) have chosen to invest part of their time and resources to perfect the modeling of nZEB and ZEB buildings. Analyses conducted on some engineering projects carried out between 2013 and 2018 in Ticino show that:
- It is possible to efficiently construct nZEB buildings, limiting additional investments to a range of 10-12 percentage points of the construction costs of new buildings;
- This extra investment can be recovered within the first 6-8 years of operation, thanks to reduced operating costs, eventually producing extra income over time;
- Tenants prefer, with equal rental costs, to lease nZEB units due to their qualitative features and the inherent comfort of the buildings;
- A theoretical energy balance is possible in nZEB (depending on whether the building is residential or commercial), with the following contributions of renewable energy:
- 280 to 330 Wp per square meter of built area from installed photovoltaic panels;
- 420 to 470 Wt per square meter of built area from geothermal probes.
The data analyses gathered from the experimental construction (five-year experience) of the first nZEB buildings, along with research, reviews of pre-existing designs, and continuous critical reflection, have led to substantial improvements in engineering and the theoretical refinement needed for designing this type of building. The results confirm satisfactory and qualitatively significant improvements, with an average energy saving of 60-80%, compared to buildings of the same volume and at least 30 years of age (System Evergreen AG – Lugano).
Buildings that go from passive to active On one hand, the technical experience in passive building envelope modeling and the use of optimized systems (hydraulic, mechanical, and technological) confirm the possibility of producing (on-site or nearby) a quantity of renewable energy that matches or exceeds the entire energy requirement of an nZEB building, either newly constructed or the result of a renovation. On the other hand, there are still some limitations regarding the storage of produced energy, the economic non-competitiveness of the necessary technical solutions, and the questionable real sustainability of the energy sources themselves.
Another critical point to consider is the limited capacity of the tools we have to store the excess energy produced. We are not yet able to store surplus energy economically and sustainably for subsequent reuse when environmental factors prevent the production of sufficient energy for self-sustenance. This is why one of the many research priorities is to meet energy “consumption smoothing” concerning a continuous time variable.
The H2 Vector: Hydrogen for Residential Use Even Ticino is contributing to this greener research, and a residential nZEB-type building is being designed that will use the hydrogen molecule (H2) as an energy vector to store, during the summer seasons, the energy required for its energy needs during the winter period. The goal of this new challenge is to achieve a “Sustainable Energy Consumption Smoothing”; in other words, to reach an energy balance between the energy required and the energy produced for the building, optimally managing energy supply and demand.
Hydrogen as an Energy Vector The hypothetical research scenarios and the new opportunities previously highlighted have guided us in conducting international scouting in favor of and support for hydrogen as an energy vector. Specifically, the analysis of industrial plants that have been producing hydrogen for about twenty years and of the few pioneering projects aimed at using H2 as an energy source for residential buildings have been a point of reference at an international level.
Giuseppe Macario
CEO & Senior Executive Project Director at System Evergreen AG