Implementation of Advanced DER EPC Business Models in Dormitories in Mannheim/Germany

摘要

The Student's Union of Mannheim (Studierendenwerk Mannheim [SWMA]) is a public body responsible for the operation of cantinas and student dormitories. With an increasing number of students and a building stock age averaging 35 years, SWMA faces the challenges of managing and permanently refurbishing the aging building stock. The eight dormitories in the Ludwig Frank quartier originate in the 1930s and 1960s and were transformed from their former function as military staff living quarters into dormitories in the mid-1990s. Now, after 2 5 years and with a high fluctuation of inhabitants, the buildings again need refurbishment to provide sufficient comfort and to comply with updated fire protection regulations. In the context of lEA Annex 61 (IEA 2016) research work, the SWMA leadership elaborated, in conjunction with the authors, a refurbishment master plan that includes a deep energy retrofit solution. IEA Annex 61 defines a deep energy retrofit, or DER, as "major building renovation project in which site energy use intensity (including plug loads) has been reduced by at least 50% from the pre-renovation baseline with a corresponding improvement in indoor environmental quality and comfort" (IEA 2016). In the case of the Ludwig Frank quartier, the energy modeling and cost-benefit optimization helped to configure a bundle of measures with a predicted reduction of at least 70% energy savings. The bundle of measures is a combination of high-performance envelope requirements, HVAC, and lighting systems, including photovoltaic (PV) power generation. As the building owner, SWMA has a limited budget; the calculated investment of approximately 3 million Euro was considered to be provided in a public-private partnership (PPP) project. Because of the strict debt limit policies for public entities, several options for PPPs were compared. Energy performance contracting (EPC) sees the energy service company (ESCO) in the role to invest, finance, implement, and operate the measure bundle. EPC provides a performance-related remuneration scheme for the building owner ("pay as you save "), which can be considered debt- neutral. However EPC has so far only been considered for HVAC measures. Integrating the building envelope means tripling the investment budget of a "normal" HVAC EPC; also, the ESCOs have no experience in how to implement a building envelope and guarantee its performance. The goal of this paper is to demonstrate how these ambitious energy targets were implemented in an advanced DER EPC business model and by which means the multiple risks were mitigated in the technical concept, the procurement structure, the award criteria, and the contract structure. This paper shows that, even with a small baseline, a DER EPC can be carried out cost-effectively by combining DER and non-DER buildings and measure bundles and by adding a cost-effective supply solution for the refurbished buildings. After the completion of the public procurement process, the Ludwig Frankproj- ect is now in the first part of the implementation phase, which means a detailed planning process and then the constructive implementation. During the detailed planning it will be assessed if the option of a second DER building would still be cost-effective. The process in the preparation phase of the project and the results of the tendering were very encouraging for ESCOs and building owners. As a pilot effort, there have also been many process-based and technical experiences that can be used to bolster future DER work in the public sector (German Energy Agency, n.d.).