Sustainability
Aug 2023
10 min
Sustainability
Interview from 05.07.2023, Melanie Bernard & Steffen Lebherz
A little more than 2 years ago, we moved into our new office building ML58 in Leinfelden-Echterdingen. The building was completely renovated by our landlord, but we invested in the photovoltaic system ourselves. This is an important step towards our goal of climate neutrality.
I spoke with Steffen, Director Project Portfolio Management & Controlling, about the idea, the planning, the hurdles, the schedule and the savings.
Melanie: Hi Steffen, let's first talk about the building and why S&P landed in Leinfelden-Echterdingen.
Steffen: We completely exhausted the expansion possibilities in the old office space due to our growth. We were looking for something new that was larger and more modern. After a long and intensive search, we came across this property. It was vacant, dated back to the early 70s, and had just that rough style we wanted. At the time, there was only a draft of what the new building should look like. Our landlord had hired an architect for the deconstruction and renovation. We were able to play a full role in the interior design and also in sustainable remodeling. We had a great deal of freedom in the design.
Our landlord said, "With a 10-year lease, you have a lot of design freedom. You can think about and realize a custom-fit setting with the architect. We then developed the concept together.
Melanie: Was the photovoltaic system planned for this building from the beginning?
Steffen: No. The property can be raised and initially I had the idea of a roof terrace. But due to the conversion costs for the fire protection requirements and the roof terrace itself, we discarded that. In short: too expensive. Then I asked myself the question, what are we going to do with the roof? I asked my colleague Horst Reichert what a photovoltaic system would be like in terms of S&P goes green.
A company from Hamburg, with technicians and sales in Munich (is closer to us), provided us with a quote with the potential savings. Energy Project Solutions GmbH is an all-in-one company that takes care of everything, from planning to implementation. That was very important to me. I highly recommend this to anyone who is not fully versed in the subject matter and has little time to deal with it on the side. It was tricky, because the construction had to be integrated into the upgraded existing building. Cables were pulled across the roof through the shaft into the basement to the inverters and from there to the low-voltage main distribution. Then to the newly set meter, through which we feed in electricity or draw electricity from the grid.
We have concluded an additional rental agreement for the roof area of our new office in order to be able to erect the photovoltaic system on it.
Melanie: Why did we decide to do this? What were the main reasons?
Steffen: Various aspects were decisive for this.
1. autonomous power generation and thus a certain independence from the electricity market. We wanted to "cap" the wild price fluctuations on the electricity market of the past years for ourselves. Unfortunately, a completely self-sufficient power generation is not possible in our latitudes. For this, the photovoltaic system would need a large, expensive storage tank. In winter, the solar radiation is therefore not sufficient to cover the entire electricity demand. Any shortfall must be drawn from the grid, but any surplus can be fed directly into the grid.
2. cost savings in the long term. According to a conservative estimate, amortization is possible after approx. 8 years.
3. sustainable power generation was one of the main reasons for us. S&P goes green. Our footprint has improved significantly as a result.
4. we also want to set a good example. When we do something for the environment, it has a positive effect on our employees. And perhaps we will also manage to persuade more companies to take this step. We have significantly improved our eco-balance. In this way, we are helping to avoid energy generation that is harmful to the climate.
Evaluation of the first-year cycle from the end of July 2022 to the end of July 2023.
For this evaluation, we use the FusionSolar app from Huawei. This app helps users monitor and control their PV panels easily and efficiently. With an intuitive interface, this app provides a complete solution for managing solar panels with photovoltaic systems.
Melanie: Were there any government plans or building specifications at the time?
Steffen: No. There were certain building requirements and an energy-saving ordinance, but a photovoltaic system was not one of them. We had to take a lot of things into account when it came to insulation. The house is completely thermally wrapped as if in a thick coat (KfW standard) and the windows are also new.
In the meantime, things look different in Baden-Württemberg: From May 1, 2022, photovoltaics will be mandatory for new residential buildings in Baden-Württemberg, and from January 2023 it will also apply to all basic roof renovations.
Melanie: Commissioning was at the end of July 2022? When was construction started? (Note: the project ran during the Corona phase).
Steffen: Unfortunately, the start of assembly had been delayed from February to April 2022 due to the difficult procurement. Originally, a realization time of 4 months was scheduled and commissioning was planned for April 2022. The plant was ready for operation from July, but then, how could it be otherwise, there were delays in the installation of the new meter and the acceptance by EnBW. This was annoying and took weeks.
Melanie: What were the biggest challenges/hurdles for construction and permitting?
Steffen: Firstly, very high bureaucratic hurdles due to authorities and the application process at Netze BW. You have to be prepared for that. Secondly, procurement bottlenecks for the substructure. The panels were already reserved with an order in December 2021, but only delivered 5 months later thanks to a missing substructure. Third, filling out all the applications. That was a heck of a job.
Melanie: What do we have for a photovoltaic system, a rooftop system?
Steffen: Yes. The system is mounted low on our flat roof. Quasi floating on the roof. It is not anchored, but only weighted down. This must be properly determined by a structural engineer.
Melanie: What does our plant do?
Steffen: The plant has 99.9 kWp (kilowatt peak). That is the maximum when the order is placed, otherwise we are considered an electricity trader and are classified differently. Of course, we feed surplus energy into the grid with our plant, that is permissible.
Melanie: Do we cover our entire electricity consumption with this or do we still buy in?
Steffen: Both. Over-coverage tends to be in the summer, when the electricity flows into the grid and the remuneration is very low, and under-coverage tends to be in the dark season.
Melanie: How much electricity have we generated with it since then?
Steffen: As of today, we have already saved 18.8 MWh (megawatt hours) compared to the previous year's procurement. In December 2023, we will then have the first full annual cycle.
Melanie: Is the photovoltaic system worth it for us?
Steffen: Absolutely. If we save around €12,000 a year in electricity, then we will have achieved the targeted ROI in around 8 years. From January to July 2023, we have saved €7,875 in procurement costs at 40 ct/kWh according to monitoring. We are therefore right on target. The plant even generates about 15% more electricity than originally assumed or calculated. Okay, of course this is also due to the sunny months this year.
Tip for the acquisition costs or the financing: We bought and paid for the plant, but then sold it again in a sale-and-lease-back process. This means that we pay a monthly premium, i.e. a leasing rate. The difference between what we save on average each month in costs and what we pay is approximately a plus of 25%. So we get more out of it than it costs us.
Melanie: Is there any money/grant from the government for businesses to install a photovoltaic system?
Steffen: No. We only receive money for feeding electricity into the grid. But that is very sparse.
Melanie: What does the maintenance and upkeep of the facility look like?
Steffen: That keeps within bounds. An inspection with visual inspection is due once a year. But we also want to conclude a maintenance contract.
Melanie: Do we have plans to expand the photovoltaic system or use other renewable energy technologies?
Steffen: No, because we have already fully exhausted the permissible expansion. Be it from the space, we have 900 m² roof and 700 m² plant and as mentioned above with the kilowatt peak of 99.9 kWp. We are only tenants and our landlord is currently not seeking any conversion in the direction of heat exchangers, geothermal probes or similar, as the property has been completely renovated and modernized. The gas heating is new as well, we purchase eco-gas. The building is insulated according to the current structural guidelines regarding thermal insulation.
Melanie: What advice do you have for companies that also want to install a photovoltaic system?
Steffen: In any case, the entire installation should be in one hand. There are interfaces to the building, for which the client is otherwise responsible and can quickly become technically overwhelmed. Other specialists are required anyway. And strong nerves (laughs). What takes a lot of time is the application and approval process and, after implementation, the necessary meter exchange and official approval for the feed-in.
But all in all, it'sdefinitely worth it.Not only for us, but especially for the environment.
