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r.e.think Story

Sustainability begins at home

A self-sufficient house

As you might expect from Günter Haug, our Managing Director at BayWa r.e., he’s passionate about sustainable living and the difference we can all make as individuals to reducing our carbon footprint.

In 2015, Günter set out to r.e. think how sustainable energy could work in a family house – his family house! The result was the remarkable Plus Energy Solar House. A key objective for Günter was to discover just how self-sufficient a solar PV house could be. Working with several of our business partners he brought together the latest thinking and technologies.

Günter has designed the whole system around two central elements, an intelligent home manager and heat pump manager. These clever bits of technology combine together and effectively communicate with each other to plan and manage the energy needs for the house on any given day.

Stiebel Eltron’s heat pump manager reports the demand to the SMA Sunny Home Manager which then plans the operation of the heat pump according to the daily forecast. If certain minimum values, such as the room temperature or temperature in the thermal storage tank, are undershot then the heat pump switches itself on automatically. Clever!

Consistent, reliable energy whatever the weather

Nearly 30 kWp of modules have been installed on both sides of the roof. In the summer they produce up to 180 kWh and in winter up to 60 kWh per day.  From spring through to early Winter, the PV energy generated covers the entire demand; electricity, hot water and heating. Sunny days or milder days in winter are also covered. 

On very cold and dark days, a conventional power supply is still necessary. But this is triggered automatically by the home manager, so people living in the house don’t notice the change in supply at all and don’t need to do anything. Zero inconvenience.

The result? The Plus Energy Solar House is able to deliver an impressive 80 per cent self-sufficiency. Meaning Günter and his family are meeting the vast majority of their energy needs from sustainable green power.

What next?

But Günter is not stopping there. The whole system has been designed to be future proof and allow new or better designs to be added.  

At the moment around 18.000 kWh, mainly produced in summer, is fed directly into the grid. So, the potential is already there for 100 percent self-sufficiency and is only a matter of storage. And even at 100 percent self-sufficiency, the addition of storage would still allow the system to meet additional demands say, for example, for an e-car. Not surprisingly, Günter is already working on this!

At the cutting edge of sustainability

The Plus Energy Solar House has proved so successful and generated so much interest that further houses are now being built in a project at the Friedberg-Hugelshart estate. A building right at the centre of current sustainability thinking in Germany.

We’re able to supply developers and architects not only with the energy concept but also with the right materials for an energy-saving and healthy building envelope. Over the next five years, we envisage equipping several hundred buildings of this kind.  

When you lead from the front, exciting things can happen.

Renewable energy […] is plentiful, sustainable, economic and available to all of us. What I perhaps love most though is its versatility. […] What we achieved with this project is to show just how self-sufficient a home can be, and also how it can be seamlessly integrated into a busy family life.

Günter Haug,
Managing Director, BayWa r.e. renewable energy GmbH

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