Germany, the home of our forthcoming Enapter Campus mass-production centre, agreed to become largely greenhouse gas neutral by 2050 by signing up to the Paris Climate Agreement. Among the many challenges associated with tackling this pledge, one hits particularly close to home: the German building sector is responsible for more than a quarter of the country’s CO2 emissions.
Although energy-efficient renovation measures, use of renewable energy and the replacement of heating systems have already begun to reduce building emissions, massive savings are still needed.
Expanding the generation and use of renewable energy is essential for these savings, no matter the location. Using locally–created energy can be transformative here, particularly when paired with flexible energy storage from green hydrogen – and especially in networked energy communities.
Networked energy communities
A networked community can be a single multi-user building or multiple buildings with energy infrastructure that doesn’t depend entirely on an external, central supply. They often exist with a direct connection between power producers and users but without a traditional network operator.
That makes producers and consumers effectively one and the same – so-called “Prosumers”.
The main goal of such a community doesn’t have to be self-sufficiency; it’s often sustainable, flexible and economical energy production. To achieve this, a networked community first needs an operator for energy production, storage and distribution. This could be a community of Prosumers (citizen energy), apartment building owners, housing cooperatives or regional energy suppliers (among others).
Photovoltaics (PV) is also a fundamental tool for many communities, and the potential for building-integrated solar in Germany alone is estimated at a huge 1 TW by Fraunhofer ISE. To put that into perspective, the total installed global solar capacity at the end of 2020 was about 0.7 TW. PV brings the creation of renewable energy closer to the user but also creates some challenges to overcome.
Tenant electricity and the storage conundrum
When owners of apartment buildings install rooftop PV modules and offer renters the power via an in-house network, it’s a networked energy community model known as “tenant electricity”. Excess power can be sold to an electricity supplier or extra energy can be purchased.
Such communities are becoming more popular around the world, with Germany looking to boost their growth through increased surcharges paid on such power through its tenant electricity scheme. Moreover, the Technovio report “Global Rooftop Solar market 2020-2024” states that the global rooftop solar market is expected to grow by 11.36 GW between 2020 and 2024.
But solar power generation and its use often aren’t simultaneous, which can lead to curtailments when energy can’t immediately be disposed of. Selling the power also isn’t necessarily the best option given the decline in feed-in tariffs paid. Another challenge: PV only produces power during the day.
If a community wants to produce the most electricity possible, use it as effectively as it can and buy less, then it has to be stored temporarily. Here’s where community energy storage comes into play.
Store energy, double self-sufficiency rates
In its 2017 Netflex Study, the German Energy Efficiency Agency (DENA) concluded that maximising energy self-sufficiency is the most economical operating strategy for smart neighbourhoods. Installing a storage system leads to an approximately doubled energy self-sufficiency rate, helping to avoid state-induced electricity charges, levies and taxes, and delivering better cost effectiveness.
Even better, optimised usage of storage systems helps avoid the wasteful curtailment of solar energy. More renewable energy can be produced and used at a later point in time.
But it’s not just the operator who benefits from the community energy concept: The users also win when energy production, storage and distribution are undertaken by an operator in-house.
They don’t have to make any initial investment or long-term rental payments, don’t have to take care of their own PV systems and can leave all administrative and legal obligations to the operator. Moreover, they can enjoy lower energy prices since they avoid state–induced charges.
Green hydrogen energy storage
The benefits of community storage are obvious and although many kinds of solutions are available, they mainly differ in storage duration and storage capacity. Choosing what technology to use is today less of a question of feasibility and rather one of features, project requirements and cost structures.
Using green hydrogen for energy storage in a community offers various approaches for coupling sectors of a networked energy community: It can be reconverted into electricity using a fuel cell and the resulting waste heat created, both from the electrolyser during hydrogen production and from the fuel cell during reconversion, can be used directly onsite in the community buildings.
Hydrogen created onsite in networked energy communities can, of course, be used in reconversion but also for the refuelling of hydrogen vehicles. Above and beyond this, hydrogen storage allows for larger amounts of energy to be stored over longer periods of time, allowing for the bridging of, for example, times of low solar energy production over winter (“seasonal balancing”).
By now, these benefits are no longer just theoretical but proven in practice.
Energy Centre of the Future
The Phi Suea House multi-building development in Chiang Mai, Thailand, in 2015 became the world’s first self-sustaining multi-house residence powered by a hydrogen-based clean energy system. Since then, hydrogen storage solutions for energy communities have advanced all over the globe.
Jumping forward to May 2021, the German real estate firm Vonovia inaugurated its “Energy Centre of the Future” in Bochum-Weitmar, a glass-clad technical centre including energy production, storage and distribution systems. Located in the middle of one of its housing estates – the “Innovation Quarter” – the energy centre delivers renewable power and CO2-free heating to 81 homes.
Our AEM electrolysers for the production of green hydrogen are among the key technologies driving the energy centre, in addition to fuel cells and heat pumps. Together, they supply households up to 60% self-sufficiently with decentrally-produced, CO2–free warmth. Vonovia already generates 25% of the electricity it needs for this locally from its own PV systems on the roofs of its buildings.
Take a tour through the Energy Centre of the Future here.
Community hydrogen for warmth and industry
Once community energy is converted into green hydrogen, it doesn’t necessarily have to be reconverted to electricity with fuel cells to be used.
In Rozenburg, a Dutch town close to Rotterdam, green hydrogen created by eight AEM Electrolysers is directly combusted for heating in innovative boilers designed specifically for this purpose. As a joint initiative from the network operator Stedin, the municipality of Rotterdam and housing cooperative Ressort Wonen, the partners are investigating the entire production, distribution and conversion chain for residential heating with hydrogen.
Another emerging approach is making green hydrogen from excess energy and selling this directly to industry, where fossil fuel-derived hydrogen is a commonly–used input in need of replacement.
This approach has been adopted in the “Climate-neutral urban quarter – New Weststadt Esslingen”, a sustainable showcase community in the southern Germany city of Esslingen am Neckar, which opened in June 2021 with 450 apartments, office and commercial space, and a university building also planned. The quarter uses excess solar energy from local PV panels and external renewable sources to create green hydrogen, the majority of which will be piped to a filling station. Here, it can be loaded into trucks to be transported to customers in the industrial or public transport sector.
Alternatively, the quarter’s green hydrogen can be put into the gas network via a feed-in station, and a hydrogen tanking station for H2-powered vehicles will also arise at a later stage.
The drive to community energy storage
In terms of technology, nothing stands in the way of the broad implementation of community energy. All of the necessary components exist and will only become cheaper in the coming months and years. Such concepts won’t just gain focus due to their environmental clout but will also attract interest for purely economic reasons, especially for multi-use concepts with green hydrogen.
Hurdles still exist in legal regulations for energy communities. In Germany, however, these are poised to make storage and consumption of self-produced energy more attractive than selling it back to the grid for many community and private solar power producers. This is true even for individual houses, as some of our partners are proving with hydrogen energy storage (article in German).
Just as producing power at home and selling it to the grid took off at the start of Germany’s energy transition in 2000, momentum is building for local energy production to be redirected towards personal utilisation – unlocked by energy storage vectors such as green hydrogen.