Boardinghaus Eching is emphatically committed to protecting the climate and the environment. We have invested a lot in recent years to minimize our ecological footprint. For example, Boardinghaus Eching has been producing its own electricity for some time. Highly efficient and environmentally friendly. Do you know what a combined heat and power plant looks like and how it works? No? Then read on.
Our own power plant
May we introduce: our Vitobloc 200 EM-20/39 combined heat and power unit from Viessmann. It produces an electrical output of approx. 20 kW and, by means of cogeneration, a thermal output of 39 kW. Similar to a car engine, energy is generated by using a fuel. However, unlike the combustion engine in a car, the waste heat generated during combustion is fed into a connected (coupled) heating system and is thus used for heating and hot water. The fuel we use is climate-neutral eco-gas from the municipal utility Stadtwerke München. Climate-neutral because the CO₂ emissions generated are offset by emission reduction certificates. (https://www.swm.de/erdgas/oekogas)
Around half of the electricity generated in Germany is still produced by conventional power plants (including nuclear power plants). The average efficiency of even modern conventional power plants is less than 40 percent, which means that more than 60 percent of the energy used is released unused into the environment as waste heat.https://www.viessmann.de/de/gewerbe/kraft-waerme-kopplung/blockheizkraftwerk.html
A combined heat and power plant goes one step further here and uses the waste heat, which can increase the overall efficiency of the plant. In large-scale cogeneration plants, this is done via district heating pipelines. However, the potential is largely exhausted in existing power plants. After all, this is only possible if there are also large heat consumers, for example residential areas, in the vicinity of the power plant generating the electricity.
This is where the idea of decentralized, combined heat and power plants (CHP) comes into play:
In comparatively small units, electricity is generated where the heat that is generated at the same time does not have to be transported over long distances (and therefore with high losses), but is consumed immediately. A large part of the losses in electricity distribution are also eliminated.
Solar heat & photovoltaics
During the day, our solar heat system contributes to the hot water supply of the boarding house. In addition, our 3 PV systems generate CO2-free electricity with a combined maximum output of approx. 47 kW.
In order to cover the power supply of our apartments to the highest possible extent from self-generated electricity, 3 BYD energy storage units come into play, which together can store up to 42 kWh of electricity and store the surpluses in phases of low demand and compensate for the increased energy demand during peak loads.
On summer days, the production of electricity and hot water from these sources is high enough during the day that our combined heat and power plant is only in use for a few hours each morning and evening.
So what do these figures mean in concrete terms?
On average, each person in Germany consumes about 1,300 kilowatt hours (kWh) of electricity per year, which corresponds to approximately 3.5 kWh per day. (Source: co2online.de)
Our combined heat and power plant operates at full capacity for an estimated 5,500 hours a year, generating over 100,000 kWh of electricity, enough for about 80 people. Our energy storage units, in turn, store enough energy to supply an average of 12 people with energy for an entire day.
Taking into consideration that part of the daily energy and hot water consumption of our residents is generated off-site, this makes us largely self-sufficient in terms of electricity as well as hot water, even with full occupancy.
In order to further reduce the ecological footprint of our guests, our new building was constructed in energy-saving KfW 55 efficiency house standard and has an individually adjustable ventilation system with heat recovery. In the event of a temporary shortage of power, the electricity produced in-house is supplemented by green electricity.