In 2021, almost six terawatt-hours’ worth of electricity from renewable sources were lost because the grid was unable to absorb it. More than 800 million euros had to be paid in compensation. The start-up decarboni1ze proposes to direct these peak loads into the boiler rooms of our cities – ideally in areas where climate-friendly heating concepts have so far been scarce. Some might remember decarbon1ze’s CEO Knut Hechtfischer from ubitricity, a start-up that turns street lamps into charging stations for e-cars, and that has been part of the Shell group since 2021. In this interview, Hechtfischer explains why he and his co-founders now rely on electrical heating elements and what basic idea from ubitricity he applies at decarbon1ze.
Compared to charging stations on street lamps, heating elements in boilers sound rather unremarkable. What do the two concepts have in common?
The original idea of ubitricity was not only charging cars at street lamps, but that each car has its own meter and unique cable ID, and that the electricity is charged in quarter-hour increments by the chosen supplier. When, where and from which source e-cars are charged is anything but irrelevant. At decarbon1ze, we applied this concept to the heating sector, building on what we had learned at ubitricity.
Our goal is to “park” wind and solar energy, which would otherwise be curtailed, in existing hot water buffer storages. All you have to do is retrofit the existing system with simple heating elements and appropriate metering units. In 2021, almost six terrawatt hours’ worth of electricity went unused. Moreover, in the coming years, PV deployment is likely to outpace the expansion of transmission systems significantly, resulting in even more excess electricity – especially in the summer. We should make use of this electricity.
How can you make use of that particular solar power?
Heating elements are controlled and monitored in 15-minute intervals. This requires a smart meter gateway, which can be installed together with the heating system. This means both projects can be initiated at the same time, as there is no need to wait for the rollout of the smart meter. Thanks to the new rollout, the costs for smart meters have significantly dropped in Germany – this makes things a lot easier.
A proprietary submeter on the heating element that communicates with the smart meter gateway via radio, enables us to record – and maintain a virtual balance – of the electricity that is supplied to the heating element by accurately allocating it to the respective balancing group. This is possible even though the we are situated behind the same metering location.
In our FlexMC research project with 50Hertz and Theben, the producer of smart meter gateways, we are currently working out the details of controlling and billing. This project will run until mid-2024. What we already do know is that the communication between the submeter and the smart meter gateway must comply with the strict security standards of the German Federal Office for Information Security (BSI), the German Act on the Operation of Metering Points as well as German and European metrology standards. It also has to be simple and affordable to enable quick integration into existing systems.
Talking about costs: If the grid charges alone are more expensive than gas, how can solar power compete with gas?
Ultimately, it will take regional and time-of-use grid charges to achieve this. This makes sense from a systemic point of view because it allows us to tap into the vast flexibility potential. We are talking about gigawatts here. We believe the German Energy Industry Act (EnWG) would allow a product-specific exception for grid-serving heating elements. Reduced grid charges would be justified in this case, as they only apply to additional consumption, for once benefiting those who aren’t homeowners who can adapt their energy management to their own solar power production. This requires an additional tool to maintain a balance.
Our concept is very efficient and inexpensive when compared to the generation of hydrogen with electrolysis: It costs thousands of euros to generate one kilowatt of gas. On top of that, it has low energy efficiency. An electrical heating element for an existing hot water storage tank, on the other hand, only costs a few hundred euros. In the future, solar power will lower gas consumption during the summer, which means there will be more gas available for heating in the winter. So we’ve basically gained gas for the winter by using solar power in the summer – but with a much higher level of efficiency and at a lower cost. It is not acceptable to pump another several million tons of CO2 into the atmosphere simply because we are curtailing green energy instead of using it – just to produce energy from fossil sources elsewhere. As long as we still have millions of old heating systems, we can use this renewable electricity through sector coupling.
Wouldn’t heat pumps be an even more efficient option?
We certainly don’t want to compete with heat pumps for electricity or use cases. We aim at multi-family dwellings with central hot water production where there’s not enough space for a heat pump, and where a connection to a district heating network is not realistic. Millions of households fall into this category.
At the same time, the regional and time-based fluctuations of grid charges – including exceptions from grid charges – are important to prevent misplaced incentives and to make sure we really “use instead of curtailing”. By powering heating elements in Bavaria with wind energy from northern Germany, as if the grid was a copper plate with no grid congestion, we would be sending the wrong message.
Our solution can be installed at short notice while immediately reducing carbon emissions, even in combination with existing gas-fired boilers. This is why the housing industry is showing so much interest.
How much do you want to advance your development in the next two to three years?
We are currently in a pilot phase working with real estate companies. In two to three years’ time, we certainly want our product to be widely available in all four control areas of Germany. By then, we should be able to scale it up to several hundreds of megawatts at short notice. Whether this will happen, and how quickly it will be implemented, will also depend on the government and major stakeholders.
