€405 Operating Costs for a Solar Electric Company Building

my-PV has already described the performance of its first solar-electric company building twice. Our results from monitoring the building technology, which consistently includes categories such as energy usage, energy sources, and PV surplus, were published after the first heating period of 2021/2022.

In the first full-year analysis, the period from November 2021 to October 2022 was examined. The results were impressive even over the entire year. With then-atypical feed-in tariffs, the results were entirely unsustainable, or more precisely, negative: my-PV received money instead of paying operating costs for the four sectors (hot water, heating, electromobility, and electricity).

Although these two analyses already convincingly support the concept of the solar-electric company building and the functionality of photovoltaic heat, one critical factor was always somewhat skewed: energy prices. These have changed massively in the calendar year 2023 compared to the last analyses. While my-PV recently recorded a five-figure income (!) for operating the building due to the completely skewed conditions in the energy market, tariffs for grid supply and feed-in are now almost back to pre-crisis levels. With costs of € 8,766 for electricity supply and revenues of € 8,361 for feed-in, the net operating costs for 2023 amount to just €405. And as always with my-PV, this amount includes the supply of all energy sectors together. This not only means the normal operational electricity (also for parts of production and development) but also the electricity for the necessary residual heat for hot water preparation and heating that could not be covered by photovoltaic surplus, as well as the electricity for charging electric vehicles (both company-owned and private vehicles).

Two energy sectors significantly increased

The immense company growth in 2023 is particularly evident in two energy sectors. While there were only minimal changes in the energy used for space heating and operational electricity compared to the last analysis, a massive increase is noticeable in hot water and electric vehicles. In 2023, the energy expended for hot water preparation now exceeds 1,000 kWh. In a typical residential building, this amount would barely cover the annual hot water needs for one person, but in our company building, hot water is primarily used for handwashing and in small amounts in the kitchen. What is remarkable about this figure is the doubling compared to the last evaluation, reflecting the company's growth and associated personnel expansion.

The same trend applies to the use of electricity for charging electric vehicles. This includes not only the company fleet but also private electric vehicles. my-PV provides its employees with free charging facilities in the parking areas, and here too, there is an approximate doubling from 2022 to 2023, with 14,700 kWh used for charging in 2023.

Also in 2023, energy self-sufficiency across 4 sectors

Our solar-electric company building has once again achieved energy self-sufficiency in its second full operational year in 2023, despite significant growth in personnel. The balance was positive at 217.7%, calculated from the net feed-in and grid consumption.

More than half of the required energy for electricity, heating, and mobility is provided by the 100 kWp PV system installed on the facade and roof of the building. Thus, 55.2% of the total energy needed for operations was directly supplied by our own solar power plant. The remaining 44.8% of the electricity demand was sourced from the grid. At the same time, more than double the amount of solar electricity generated was fed back into the grid. Self-consumption reached 36.2%, a remarkable achievement for a system of this capacity and consumption profile.

This was made possible by my-PV's products, which efficiently utilize even the smallest surpluses of solar energy with high precision and compliance to grid standards, especially for generating photovoltaic heat. This applies not only to hot water but also to solar-electric heating through component activation via heating wires.

Annual performance factor of 6.38 achieved in 2023 for the solar-electric concept! But how can an all-electric building technology have an annual performance factor?

An electric heat generator by itself does not have a performance factor, much like the water circuit of underfloor heating. It is only the entire system that enables such a factor. For the heat pump, the necessary components are the evaporator, compressor, condenser, and expansion valve. The evaporator absorbs environmental energy, with the ambient air serving as the heat source for air-source heat pumps, warmed by the sun.

In the solar electric variant, the photovoltaic system now takes the place of the evaporator. The original source of environmental energy remains the sun. The energy carrier now is electrical power instead of a refrigerant; thin cables replace not only complex piping systems but also intricate technology that cannot function without regular maintenance.

For the solar electric concept, photovoltaics serve the same function as the evaporator does for a heat pump.

The significant advantage is that electricity, rather than heat, is now available for energy distribution. "Cables instead of pipes" make the system considerably simpler and more cost-effective. This characteristic also significantly reduces maintenance costs.

Conclusion for the operational year 2023 of our solar-electric company building:

In the low-energy buildings of the future, everything is electric, mostly solar-electric. This applies – as repeatedly demonstrated - from now on even to heating in commercial properties. Compared to conventional heating technology with heat pumps, my-PV's company building had lower investment costs and incurred operating costs of only €405 last year. This incredibly low figure includes not only electricity demand but also costs for hot water, space heating, and electromobility!

Heat generation without moving parts is not only completely maintenance-free but also completely silent. "Cables instead of pipes" simplify installation and operation. The concept of solar electric heating is suitable for low-energy buildings and, with appropriately sized photovoltaic systems, is also clean and sustainable!