A renewable multigeneration energy system for a public school in Denmark

Distributed energy resources are becoming increasingly popular in times of energy volatility caused by large price fluctuations in the energy markets. It is therefore pro-actively interesting and advantageous for energy-heavy consumers if they establish renewable multigeneration systems to partly cover their own energy demand. Multigeneration systems create both low-emission energy and have the potential to yield positive impacts in terms of the total energy price and the economic feasibility of the energy generation solutions for the consumer. By implementing linear programming, a well-documented optimization method, this paper sets out to construct an open-source framework that can be used to evaluate different distributed renewable energy resource combinations for different types of consumers. This framework will make it possible to evaluate known and thoroughly tested technologies in combination with alternative technologies to determine the potential of investment. To showcase this possibility, scenarios containing different energy supply technologies were examined to determine the optimal technology mix and production plan for a public school located in Southern Denmark. The findings highlighted that the socioeconomic benefits of utilizing photovoltaic-thermal technology are very promising and have a large potential. Nevertheless, the combination of photovoltaic technology and heat pumps was the best overall scenario because of its ability to generate relatively cheaper energy while also maintaining socioeconomic benefits. This is especially important because it fits into the Danish plan for district heating expansion and reimbursement. The paper illustrated how the framework can be applied in combination with different technologies to determine the most efficient scenarios. The proposed technology combination of heat pumps, district heating, and photovoltaic units would, after implementation, be able to save the public school around 6.7 MDKK in a period of 20 years, with a payback period of around 9 years. It was shown that, within the specific multigenerational system proposed, heat pumps would cover 92% of the heat demand but would not be sufficient in peak load hours; therefore, district heating will be needed as a support.