The Green Parking Space – Utilization of urban parking areas for production of biomass
Starting point / motivation
Some traffic and parking areas in urban regions are only occupied for a very limited amount of time. In particular, this is the case for parking areas of large, suburban cinema centres which are mostly used only in the evening. Also parking areas of large suburban shopping centres are largely occupied only in the late afternoon and on Saturdays. The rest of the week these areas are unused and possess neither productive nor decorative function.
At the same time, a major problem for large-scale implementation of renewable energy, in particular solar energy and bioenergy, is the massive land use which results from the low energy density of solar radiation. As it has been remarked repeatedly and correctly, intensive use of renewable energy can demand areas which are either of high ecological value or would be needed for other purposes (in particular the production of food and animal fodder).
Contents and goals
It seemed desirable to employ sparsely used ground-sealed areas, which are already lost for ecology and for food production, for additional production of energy.
While there are approaches for the use of traffic areas for photovoltaic purposes, the potential for production of biomass, for example by cultivation of microalgae, has not been analysed so far. This type of use would offer the advantage that besides the possibility for energetic use, the harvested algae could also be used as raw material for bio-refineries or for fertilizer production, allowing for cascade use.
Since this approach is quite new, a main goal was to estimate the potential for this type of energy and raw material production, based on data on land use, weather data and known characteristics of microalgae. Another goal was to gain an overview over different possibilities for implementation and the specific challenges (e.g. mechanical stability, optical properties, safety aspects).
In particular we have devised a concept for the use of photobioreactors, which are directly integrated into the traffic areas. Whenever possible, we collected proposals for possible solutions to foreseeable problems, e.g. photo-inhibition and protection against freezing.
For the analysis, literature research (including analysis of weather and land allocation data), basic scientific-technological reasoning, scientific calculations and simulations with computer models (yet to be devised) was used.
From results of calculations and simulation we have derived a catalogue of criteria to describe which approaches seem feasible, which minimum requirements the construction materials have to fulfil and which are the limiting economic factors for a profitable implementation.
Based on these results, the approach was compared with alternative concepts (like photovoltaic use and light harvesting) and strategy recommendations will be devised. All in all, this project yielded new approaches and insights for biomass production on spaces already used for traffic and will therefore offer new perspectives for management of energy and substances in the urban environment.
Project or cooperation partners
- Vienna University of Technology, Energy Economics Group
- University of Applied Sciences Wr. Neustadt, Campus Wieselburg