Managing energy with software - intelligently and sustainably - Energy saving series part 3

In 2019, Strähle Galvanik in Zaisenhausen was the first company in Baden Württemberg to take part in the WIN4Climate project, which focuses on processes and solutions for decarbonizing and increasing the flexibility of heat supply in industry. The project was supported by the Karlsruhe University of Applied Sciences. At that time, the first flexible control system for electricity price-based regulation was installed in practice in an industrial company.

Zaisenhausen's mayor approached Strähle CEO Sven Reimold in 2018 and explained that the district of Karlsruhe was working on a project with the Karlsruhe Environment and Energy Agency (UEA). The UEA wanted to use a central industrial area to shift waste heat and surplus electricity between the companies. In other words, one company produces too much waste heat and electricity than it needs itself, a neighboring company needs both and takes it. Sven Reimold immediately agreed to take part in the project.

The crux of the matter: regulations and bureaucracy. Because anyone who sells electricity to third parties needs to know that customs will come into play. They say how, what and who can do the electricity business and under what conditions. It was about electricity tax, calibrated electricity meters or even contracts with the grid agency, but initially has nothing to do with feed-in contracts for photovoltaic systems. There will be a separate chapter for this. It quickly became clear that this would not work. From the Karlsruhe Environment and Energy Agency, we finally came to the Karlsruhe Institute of Technology via the Karlsruhe Energy and Climate Agency.

In 2019, three clever young engineers set themselves the goal of relieving the power grids when there is a surplus of electricity and feeding it into the grid when it is needed. They were looking for companies that had already dealt with the matter relatively intensively. The company Strähle was already at the desired level in 2019. It was integrated into the spot electricity market and used photovoltaics and combined heat and power plants. However, some adjustments had to be made in addition to the software. For example, more buffer storage for hot water was required. The primary task of the software was to produce electricity and heat for operation. In the event of an electricity surplus, the grid was to be relieved via an electricity price in the negative range. Advantage: Industrial companies with surplus electricity receive cheap electricity or are even paid for the electricity they use. The table shows the control settings. A distinction is made between heat-controlled, electricity-controlled, electricity output-controlled and peak power-controlled. A total of 19 control modes are available.

Energy management with electroplating software

Together with our long-standing partner Hehl Galvanotronik, a number of energy-saving modules have been programmed into the Galvanos control system. There is the End of work button. With this function, for example, all pumps, units and valves for air that are not required are closed and switched off. There is also a time control for public holidays and weekends, where heating and extraction can be explicitly throttled or switched off at certain times. With extraction systems in particular, it is not necessary to operate them at maximum power at weekends. A good middle ground can be found here using frequency converters, where a motor with 7 KW can be throttled to 5 or 4 KW.

3 KW x 48h = 144kwh x 48 weekends x 13 cents = 898 euros saved per year on extraction (example calculation, everyone must calculate their own motor power and local conditions / electricity prices).

Intelligent electricity and heating control

With the heating control system, Strähle has not only integrated the intelligent and extremely energy-saving pumps, but also created a link between the pool heating system, the power control system and the galvanic software. This interaction constantly monitors how much heat and electricity is currently required for which system.

Consequently, the control system can then decide whether to heat, reduce the peak load or switch the CHP units on or off.

In this way, the drum system could also continue to be operated more or less economically.

(First steps towards energy efficiency, energy saving series no. 1 in Galvanotechnik 8/2023). These measures alone have enabled electricity costs to be reduced dramatically.

The energy supply company charges up to 180 euros per KW for high loads (peak loads), depending on the power price factor. As the Strähle company only runs production in two shifts, the duration of use is less than 2500 hours per year. This means that the company only pays 54 euros per KW.

Under 2500 hours of use

Year 2012: 550 KW x 54 euros = 29,700 euros performance price

Year 2012: 2,000,000 kwh x 4.4 cents = 88,000 euros grid usage.

Total costs: 117,700 euros

Over 2500 hours of use

Year 2012: 550 KW x 180 euros = 99,000 euros performance price

Year 2012: 2,000,000 kwh x 1.2 cents = 24,000 euros grid usage.

Total: 123,000 euros

Under 2500 hours of use

Peak load management year2022: 260 KW x 54 euros = 14,040 euros performance price

Year 2022: 540,000 Kwh x 4.4 cents = 23,760 euros grid usage.

Total: 37,800 euros

This example in particular shows that saving electricity pays off! Otherwise the Strähle company would pay at least 80,000 euros more today (sample calculation, each company has different conditions and must calculate these itself).

However, the grid operator is still missing here. This is because it now calculates the output based on consumption. The grid fees per Kwh (Electricity Grid Fee Ordinance) are being gradually increased every year. In 2013 it was 6.52 cents per Kwh, in 2022 already 8.12 cents.

Peak shaving through load control

Peak shaving means smoothing out peaks. At Strähle, load management or peak load management is not achieved by dispensing with a consumer and also not by load shifting, as suggested by many energy supply companies. As explained at the beginning, the company takes the approach of producing more electricity by controlling the electricity price-based control system, which, for example, shuts down units at the barrel system when consumption is high, but does not switch them off completely.

The electroplating plant has committed itself to further reducing emissions. The PATHTOZERO project was launched in 2022 in collaboration with KIT Karlsruhe. The PATHTOZERO software is to be used to determine which units Strähle can use to position itself for the future and what potential long-term procurement contracts for green energy such as Power Purchase Agreements (PPAs) have for the company's two sites. Investments and holdings in renewable energy plants away from the sites can also be part of the solution.

In the next issue: Integrating PV systems, making the right use of self-generated electricity through CHP.