Berlin, November 2021 (PRG) – Missed climate targets in the building sector, missed targets in residential construction – the previous government left the new coalition with a heavy mortgage. In an interview, Dietmar Walberg, managing director of the Arbeitsgemeinschaft fur zeitgemabes Bauen (ARGE //eV), explains why climate neutrality and cost optimization need to be thought of on a large scale.
Mr. Walberg, last year, the building sector was the only sector that failed to meet its climate targets. Why is that?
Dietmar Walberg: The reason for this is that the targeted climate neutrality cannot be achieved with a one-sided focus on energy efficiency. Energy cannot be saved in buildings at will – even if marketing promises of the zero-energy house suggest otherwise. Every building needs energy to perform its basic functions. And if, as is currently the case, most of this energy comes from fossil sources, CO2 is emitted. A climate-neutral building stock will only exist when the buildings are completely supplied with renewable energy.
According to a study by McKinsey, CO2 emissions in the building sector could be almost completely reduced by "green" electrification. Could this be the game changer?
Dietmar Walberg: "Alongside energy refurbishment, green electrification will certainly play a key role in the decarbonization of the building stock. Since half of the German electricity mix still comes from fossil fuels, it would make sense to redirect some of the subsidies earmarked for energy efficiency to the expansion of renewables. As transportation and industry also switch to renewable electricity and green hydrogen, energy experts say electricity demand will increase from the current 545 to 745 terawatt hours by 2030. Considering that it currently takes up to five years to plan and obtain approval for a wind turbine, the new German government must ensure that the pace is significantly faster. What is currently holding back green electrification is the price of electricity, which at 30 cents per kilowatt hour is far too expensive. Cross-neighborhood solutions are a good way to supply many buildings with climate-neutral and cost-optimized energy already today. And this at a price per kilowatt of 9 to 12 cents, which is significantly lower than the normal cost of electricity.
Around 75 percent of all buildings require energy refurbishment.Nevertheless, the annual renovation rate remains at one percent. Why is that?
Dietmar Walberg: This is due to the current funding approach, which is far too small-scale. Bringing existing buildings with poor or mediocre energy efficiency up to high-end standards is not only disproportionately expensive, costing up to 180 billion euros per year, it is also slow going due to a lack of tradespeople. We need to think on a much larger scale when it comes to energy-efficient building retrofits. Moving away from individual subsidies and toward district-wide solutions that enable energy compensation between old and new buildings as well as commercial and residential buildings. This creates synergies, reduces the need for renovation on the individual building and saves costs.
Many architects and planners criticize the fact that the ever-increasing energy efficiency standards are no longer in proportion to their benefits. What would be the alternative?
Dietmar Walberg: Indeed, at a certain point it no longer pays off. Meanwhile, we've driven it all up to the point where an efficiency house 40 standard adds 264 euros per square meter to construction costs. The alternative would be a smart climate architecture. Instead of installing more and more insulation and energy-intensive ventilation or even air-conditioning technology, we should focus more on open-technology CO2 savings and robust constructions and, for example, make greater use of the thermal storage capacity of mineral building materials. How masonry buildings are able to buffer heat in the summer and keep heat indoors longer in the winter. Combined with intelligent ventilation concepts, a reduced heating requirement can be generated as a positive side effect.
In early October, the Federal Statistics Office reported the sharpest increase in construction prices in 51 years. How can affordable housing be created in light of these?
Dietmar Walberg: Affordable housing always starts with the economics of the construction method. Therefore, typified building can make a significant contribution to solving the problem. In a study on cost-optimized construction in multi-storey housing, we investigated how individualized, serialized and typified construction differ in a direct cost comparison. The most cost-effective option proved to be the typified masonry construction with 1.950 €/ m 2 living space – if certain conditions are met. For example, the project must comprise more than 50 residential units, have as few project-specific features as possible and be built to a maximum of the 70 efficiency house standard. Another way to create affordable housing at low cost is to repurpose vacant office buildings. Due to the increased trend toward home offices, less and less office space is needed. By 2023, there could be 235.000 apartments are being built. And at a cost two-thirds less than a new building. In addition, there are numerous other levers that can be pulled to reduce construction costs. I was a member of the Construction Cost Reduction Commission, where six years ago we worked with other experts to come up with 71 recommendations, very few of which have been implemented yet. In the paper, the new federal government still finds many suggestions for cost-optimized construction.
Let's assume you are the new Federal Minister of Construction. What would you do to meet climate targets and create affordable housing?
Dietmar Walberg: The first thing I would do is set up a round table where all the relevant players regularly exchange ideas on the topics of climate neutrality, decarbonization of the relevant building materials and cost optimization in housing construction, and agree on concrete strategies and funding programs. In parallel, I would turn the subsidy landscape completely upside down and instead of over-optimizing individual buildings, promote concrete CO2 savings – open to technology – on the building and increasingly neighborhood solutions. In addition, a training initiative urgently needs to be launched. Currently, one in four architects and engineers is over 55 years old. When they retire in the next ten years, there will be a shortage of about 45.000 skilled workers. The situation is even more dramatic on the building sites, where in the next ten years 150.000 employees retire from the workforce. This is one in six employees. To close this gap, recruitment agreements should be launched as in the 60s.