REE-Mix - regional renewable energy


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REE-Mix entrepreneur team, David Elsaesser, Peter Stahlschmidt and Stefan Jergentz from the Institute for Environmental Sciences, University of Koblenz-Landau

Planning tomorrows renewable energy supply

The energy system is a changing. The climate change is an enormous task for mankind putting the reduction of CO2-emission on the global agenda. We have to stop to burn the dirty fossils and to use the risky nuclear, heading towards the sustainable solar age. The current energy supply is centralized, characterized by huge power plants providing power to thousands of households and industrial complexes. The increasing application of renewable energy supply will change the landscape due to their decentralized character. The land-use will develop towards a requirement of areas utilized for renewable energy plants. The change in land-use patterns will lead to a conflict with the conventional use of the land which requires a resource management.

GIS and energy

Geographical Information Systems (GIS) are very good suited to assess the potentials of renewable energy sources in a region due to their close connection of regional energy production and land-use patterns. Several approaches using GIS assessing the energy potentials of areas deal with different scales. Klärle et al. (2009) developed in the SUN-AREA project a GIS procedure to calculate the suitability of roofs for photovoltaic modules for some cities in Germany. Izquierdo et al. (2008) estimated the geographical distribution of the available roof surface for the large-scale photovoltaic potential for Spain. The renewable energies wind and biomass are very closely connected to the local conditions. The site of wind energy plants depends on wind speed and local regulations such as distance from houses and conservation areas. Biomass plants need organic substances in the close surrounding. Established GIS procedures to plan wind energy and biomass plants focus only the scale of the single plant and are often not within the frame of a local energy concept. What is missing is an integrated management of the renewable potentials of a region to foster a better planning for the extending renewable energy supply.

REnewable Energy-Mix, REE-Mix

The aim of the REE-Mix approach is to assess the implementation potential of renewable energy in a region and to build future energy scenarios.

The REE-Mix approach consists of different modules that can be applied to a range of topics addressing local climate protection initiatives. In total REE-Mix approach can be used to create a complete energy concept for a region (village, municipality, small city) based on renewable energy, energy efficiency and energy saving. Single modules can be used to issue specific questions where more detailed assessment is required. The modular setup of REE-Mix is taking the specific situation of a certain region into account. The set of modules is adjusted to local requirements. Application of single modules at a later date is possible. REE-Mix is designed to meet the requirements of a climate protection plan, e.g. in the framework of the EU Initiative Covenant of Mayors. Firstly a baseline emission inventory is prepared with the inventory module. Secondly the potentials for renewable energy, energy efficiency and energy saving are assessed with the module REE-Mix toolset and the module for Efficiency/Sufficiency. The joined estimations are optimized in energy scenarios which build the basis to develop the Sustainable Energy Action Plan (SEAP).

Inventory module

A baseline emission inventory calculates the CO2 emission of the energy supply (electricity and heating) and of several sectors such as housing, industrial, commercial and transport. It represents the current state of a region. Indicators are the energy consumption per person and the global heating gas (GHG) emission per capita.

REE-Mix Toolset

The REE Mix toolset includes all renewable energies and executes the three assessment levels (yield assessment, feasibility assessment and assessment of infrastructure) for each energy type based on GIS layers. As a result, these layers will be blended to several energy scenarios of the local developable potential of renewable energies.

Assessment modules

Yield Assessment: REE-Mix calculates the potentials for the relevant renewable energies on a local scale in GIS. This potential will represent the technical potential as a maximum of energy that can be obtained from the region. The area available for renewable energy is connected to the estimated yield of energy.

Feasibility Assessment: The technical potential is reduced by socio-economic factors which are in conflict with the local use of renewable energy. Hoogwijk (2004) highlighted the economic potential and the implementation potential that is mainly driven by policies and social issues. The feasibility assessment integrates the socio-economic aspects in the REE-Mix approach. In a current study a rough stakeholder analysis was realized of the use of photovoltaic in the city of Landau. The number of stakeholders was correlated with the size of the suitable roof surface for photovoltaic. It was assumed that big roofs with few stakeholders provide more easily access to install photovoltaic modules due to economic benefits by subsidies. Also municipal legislation issues are integrated based on single layers into GIS such as listed buildings, conservation areas and planning law.
One crucial aspect related with the expansion of renewable energy plants in the landscape is the acceptance of the new technology by the local population. Renewable energy is present in the close neighborhood, e.g. wind energy plants are visible over a great distance, biomass plants may cause olfactory annoyance and moreover transportation traffic.

Assessment of Infrastructure: There is a need to restore common energy infrastructure due to the local and decentralized character of renewable energies. The dependence on sunshine and wind makes the renewable energy volatile, which requires new concepts in managing the energy supply such as “virtual power plants”. Future energy systems will be demand-driven which changes the role of the local energy supplier. The energy infrastructure will play a key role in prospective energy storage technologies and the concept of electric mobility. In terms of energy efficiency a GIS can identify areas that can be delivered by industrial waste heat to implement networks of local heat.

Efficiency/Sufficiency module

The potentials of energy efficiency and energy savings are assessed in the third module. Especially the sector housing and transportation can be measured using GIS. The energy demand of buildings is simulated via 3D modeling setting up scenarios of redeveloping buildings. New mobility concepts such as electric vehicles are modeled related to the energy infrastructure. The module helps to identify locations for cogeneration plants and to implement local heat networks.


The previous estimations are joined in the optimization module to build energy scenarios for the region. It is possible that various scenarios are created by the model which needed to be discussed and agreed by local stakeholders. REE-Mix should reveal the opportunities for renewable energy supply and energy efficiency potentials for the region. REE-Mix serves as a basis for decision making in all energy and climate related aspects of sustainable energy action plans.

The REE-Mix project is funded by the exist program of the German Ministry of Economics and Technology and the European Social Fund

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