Master's Thesis Thomas Remmel
Modeling and optimization of landlord-to-tenant electricity supply concepts in apartment buildingsCopyright: EBC
Since the adoption of the “Tenant Electricity Act 2017“ and the subsidy for directly consumed electricity from photovoltaic systems, interest in tenant electricity models has increased. The present paper develops a model for determining a cost-optimal system design (photovoltaic system, combined heat and power plant, boiler and storage solutions) for tenant electricity projects in multi-family houses using the example of Bremen.
The model includes a solar yield calculation, the subsidies under the “Tenant Electricity Act“ and “Combined Heat and Power Law“ as well as all economically relevant parameters, whereby statements and estimates can be made about the economic efficiency of a tenant electricity project from the operator’s point of view. A tenant electricity project with electricity and heat demand can achieve a yield of 5 % with a minimum number of participants of 13 housing units. For smaller numbers of participants no economic operation can be represented. Considering an apartment building without heat demand, the yields are significantly lower. In order to achieve a return of 5 %, 30 participating residential units are required.
As a result, adjustments must be made to the “Tenant Electricity Act“ in order to ensure that projects with fewer than 25 residential units are also economically viable. Two scenarios have been developed and evaluated for this purpose. Overall, an improved economic operation could be presented. However, there is still no economic incentive for a participating number of less than 10 residential units to be generated by the tenant electricity subsidy. Important factors that influence the profitability of a photovoltaic tenant electricity project are the composition of the electricity price and the amount of solar radiation, which vary from region to region. The “Tenant Electricity Act“ does not address these regional differences with the promotion. This results in different, location-dependent framework conditions for tenant electricity projects. In order to promote the expansion of photovoltaic systems on multi-family houses throughout Germany, it is recommended to adjust the remuneration to regional conditions.