Abstract for Ecocity World Summit 2023

Our collaborative abstract for the Ecocity World Summit 2023 conference is titled "A review of life cycle assessment (LCA) studies on green roofs and walls".

Green infrastructure (GI) is often presented as a promising measure to help reduce climate change pressures in dense urban areas. This benefit, combined with the fact that GI involves increased biodiversity leads to it being seen as a sustainable measure. However, few studies quantify GI’s water and energy impacts, thereby obscuring how environmentally friendly such infrastructure can be. To elucidate the known results so far regarding the environmental impacts related to energy and water use, such as climate change or freshwater scarcity, a systematic review was performed.

Scopus was used to gather studies for an in-depth analysis of life cycle assessment (LCA) studies with a focus on green roofs and walls and energy and water use related impacts. Project details were analyzed when available, specifically for the precise types of green infrastructure applied, the local climate circumstances, the applied construction materials and plant species, the building type and specifics, and the intended climate change adaptation benefits. The characteristics of the LCA studies analyzed include the type of software and databases used, the system boundaries and functional unit applied, the cut-off criteria, water and energy related environmental impact categories, main conclusions, and research gaps.

The analysis of the results can be used as concrete recommendation for designing and constructing a long-term monitoring setup of green roofs and green walls at the University Twente, the Netherlands, as part of the Living Innovation Lab (LILa), with respect to the question of what is the most environmentally friendly way to design green roofs and green walls.

This abstract is submitted by University Twente researchers Karina Vink, Joao Santos, Markus Berger, Peter Chemweno, and Vrije Universiteit Amsterdam researcher Nicolien van der Grijp. 

Examples of local Green Infrastructure

There are many locations of Green Infrastructure to visit in Enschede. Here are two movies from the stream restoration project in Stadsveld. The stream has been restored both through existing streets and at a local elementary school. 

The municipality approached the school about their plans to restore the city stream alongside the school. They asked "can we use your schoolyard as a water buffer? If there is a lot of rain in a short time, we can collect the water in your school yard." The school thought that water and children are a beautiful combination. The schoolyard had been outdated for years, and they saw this as a great opportunity to immediately redevelop the entire schoolyard. They have had a lot of contact with the people of the municipality, including the water engineers and designers. They looked at what the municipality could contribute to this project, especially financially. They then discovered that the province of Overijssel was planning to make all schoolyards green. And that as a school you could apply for a subsidy of 10,000 euros. The municipality then helped the school plan everything. Additional funding came from Jantje Beton, an organization for youth facilities, and the ABN Amro Foundation, a bank. The school also involved children in making the plan. There were classes explaining what the Stadsbeek is and why it is important that it is there. Children also chose new playground equipment. In the design it is ensured that the depth of the retention area poses no danger to the safety of the children. Now there are classes outside and children play outside much more often.   

Exploring the multi-functional roof sector in the Netherland

Exploring the multi-functional roof sector in the Netherland - Daan Jongbloed, VU Amsterdam

Final Presentation Thesis (Dutch)

This study looked mainly at multi-functional roofs, such as green roofs with solar panels or a recreation function. A limited amount of sources were available as many companies had no time in their schedule to respond.  The main conclusions were that the materials used in constructing multi-functional roofs are already quite circular, and that the biggest improvements can be made in construction methods and reducing financial costs.

It remains unclear to which degree the entire life cycle of materials is taken into account, which is one of the reasons the LILa-GI is researching just that.

 

What is the Living Innovation Lab?

 What is the LILa?

The Living Innovation Lab (LILa) is a joint initiative of the faculty of Engineering Technology (ET) and Geo-Information Science and Earth Observation (ITC) at University Twente, the Netherlands. Its goals:
- provide a semi-controlled setting for observation, monitoring, and experimentation
- support training and education for vocational schools, university students, and practitioners
- connect with local communities and industrial partners
Green Infrastructure is just one among over a dozen of research projects taking place. Click here for more information on the other research projects at this site.

Green Infrastructure
In the initial stage, three different types of green roofs are in development, along with three different types of green walls. The green roofs include extensive and intensive green roofs, and blue-green roofs. The green walls consist of free climbing soil bound plants, scaffolding climbing plants, and wall forming modular vegetation. Both green roofs and green walls are compared to a section of building without green infrastructure, to assess performance comparatively. A later stage includes the transformation of parking places to have permeable pavement and underground water storage adjacent to the LILa site. 

Climate Change
Green Infrastructure can help to reduce the imapacts of climate change in two ways. One way is adaptation, to change our environment and increase resilience. An example of this is planting trees that increasee shade in hot summer months. The second way is mitigation, to reduce the levels of green house gases in the atmosphere. An example of this is that trees use CO2 to grow and thereby remove some from the air.
Most importantly, building green infrastructure can only be truly sustainable and thereby not add to greenhouse gases or other excessive consumption by paying attention to the entire life cycle, from production to the end of life, of the materials involved.

What are the research questions?
Two main research questions are answered through LILa - GI. The first concerns the quantified energy and water tradeoffs of GI.
To answer this we aim to quantify the potential climate resilience benefits:
- reduced urban floods and runoff peaks
- reduced heating/cooling
- carbon sequestration
and quantify the potential tradeoffs:
- CO2 emissions during production, maintenance (for irrigation and pumping), and end of life
- required irrigation and stored precipitation
all through continuous monitoring and modeling.

The second research question is how a supposedly sustainable measure as GI can be constructed in a most sustainable way, that is to say, not just be sustainable during its use phase, but also during material selection, construction, and end-of-life. To answer this, both Life Cycle Analysis modeling and intense cooperation with designers and construction companies are implemented.

Visiting

Do you want to visit the LILa - GI site with a small group? Send an email expressing your interest.

Location at University Twente
You can visit the LILa at University Twente. It is located at the road De Achterhorst, between buildings 31 (Windpark) and 32 (BMC) on the campusmap. Public transportation and access routes can be found in this campusmap.

Current impression
The LILa site is still in the development phase. At the moment you can see poles and signs where the various studies are planned to be constructed.