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Interview

Field report: A virtual power plant for the Smart City Rheintal

0 6 min

The initiators of the Smart City Rheintal project are the state of Vorarlberg and illwerke vkw, the state’s largest energy provider and head of the project consortium. In this region, they can build on numerous energy, mobility, and connected city initiatives bundled into “Smart City Rheintal” since July 2012. The goal is to make the region as energy‑independent as is technologically feasible by 2050 – preferably supplying all of the region’s energy from renewable resources. But what solutions are economically viable, now and in the near future? And what new ideas are the region’s residents willing to accept? Answering these questions is the most difficult – and most exciting – part of the project, which is scheduled to run until July 2015.

In many respects, the project is in a favorable position:

  • Over 90% of the region’s energy demand is already being met with renewable resources, particularly hydropower.
  • The project can draw on comprehensive experience gained developing smart grids.
  • Civic involvement has a long tradition in the area.
  • Besides the state and illwerke vkw, other project participants include research and IT companies and especially residential and commercial property developers. This energy testing site of the future is therefore grounded firmly in reality.

Rheintal

In the Austrian state of Vorarlberg, the Rheintal area lies between the towns of Bregenz and Feldkirch. It is a densely populated metropolitan area with about 240,000 people.

Today, stakeholders are working on “energy provision of the future” as one of three areas of innovation. Here the focus is on setting up smart grids that are bidirectional: from the grid to the facilities (producers, consumers, storage units) and vice versa. A major subproject involves building a virtual power plant (VPP) as a way to learn how to balance feeding power into the grid and taking it out.

I talked to Michael Schlauch, manager of the project at Bosch, about where the project stands.

STEFANIE PEITZKER What aspects does the region’s new virtual power plant, or VPP, combine?

MICHAEL SCHLAUCH Vorarlberg Netz, the area’s distribution grid operator, has already launched a pilot with 500 smart meter installations. The goal is to learn what measures consumers will accept for improving energy efficiency.

As a partner in the Smart City Rheintal project, when it comes to the region’s virtual power plant we aren’t focused on scaling, by which I mean reaching critical mass. Instead, we want to understand the key components it requires and how to combine these in a network so that the testing site becomes reality. We have already linked up several of these components: PV facilities, electromobility charging infrastructure (namely, charging spots and electric vehicles from car-sharing companies), various consumer devices with a certain potential for flexibility (especially heat pumps and electrical boilers equipped with storage units) as well as additional battery storage systems.

Graphic with Virtual Power Plant (VPP) and related smart grid components Source: Bosch Software Innovations
Figure 1: The VPP for the Rheintal region links together 4 core components

What exactly do the sponsors expect from incorporating these elements into a VPP for the region?

At the moment, we are integrating PV facilities in one district into the VPP. We will aggregate these to form a pool of facilities and use that to calculate day-ahead forecasts for power generation. Further districts have already been announced.

Michael Schlauch

Michael Schlauch is the Bosch project manager of the Smart City Rheintal project. Bosch Software Innovations is a partner for a subproject, which involves building a Virtual Power Plant (VPP).

To compare with the PV generation forecasts, we use the VPP to monitor the facilities’ actual power generation output every 15 minutes. In this way we can improve the accuracy of our forecasts. Figure 2 compares the forecast and the actual electrical output of a facility over a period of several days.

The more facilities we bundle together, the more we can take advantage of their flexibilities and optimize the overall system. Currently we are looking at creating a local energy supply and successfully balancing generation and consumption at the local level. Taking a broader view, we are aiming at bigger goals such as peak shaving – and ultimately avoiding an expansion of the grid infrastructure.

By integrating the electric charging infrastructure, we want to give priority to charging EVs when we have a surplus of power from PV generation. We’ve integrated several charging spots and electric vehicles from car-sharing providers into the VPP. To realize a particular timetable (for example, noon – 3 p.m. the following day), many variables for the relevant period have to be taken into account (Figure 3). These include the forecast output of the PV facilities, the load profiles of the participating consumers, what priority the consumers have, the power required by the vehicles and ideally the load profiles of the charge spots. To do that, we have to access the data from the vehicles and the charging infrastructure. For the vehicles that means especially the state of charge (SOC) and possibly also reservation data, which we receive from the car-sharing companies. Load control is not easy…

Graphic with e-mobility load management system Integrating the electric charging infrastructure into the region’s Virtual Power Plant (VPP) Source: Bosch Software Innovations
Figure 3: Integrating the electric charging infrastructure into the region’s VPP

That brings us to consumer devices in households, which are supposed to be turned on or off according to defined threshold values. In the project, this takes place based primarily on the generation forecast time series for the next day. Who is responsible for deciding what device gets switched on or off? What does the technology require? What data do we have to integrate? We are looking at

  • technical management (heat pumps, etc.),
  • integrating the relevant data (from the EXAA electricity exchange in Vienna, if we are also to send price signals – see figure 4)
  • defining and implementing the threshold values and
  • prioritizing the consumers.

Algorithms for switching on or off can be made as sophisticated as necessary, which Vorarlberg University of Applied Sciences is currently working on. We’re learning how we can actively and effectively regulate the load on the consumption side – along the lines of demand response (DR).

And finally, we are integrating battery storage systems into the VPP. They are a key element for intermediate storage and thus for everything that we want to accomplish. The storage system in this project is a pool of interconnected car batteries. Battery management will be on the agenda over the next few months. The VPP is responsible for signaling when the batteries deliver power and when they should be charged.

Right now, it’s not so important what elements we’re integrating or how many facilities we have. What is important is the combination and connectivity of the various consumers, generators and storage systems, which is teaching us a lot.

What have you learned from the VPP activities?

I’d like to focus on two lessons we’ve learned:

We still see major room for improvement in the forecasting process. That applies to the generation forecasts for the PV facilities as well as the consumption forecasts for consumers at home. Here longer time frames are needed that go beyond the end of the funded project. That’s the only way to extrapolate practical and individualized consumption profiles for particular housing units, for example. Thanks to our collaboration with Vorarlberg University of Applied Sciences and specialized IT companies, we are well on our way to obtaining this type of forecast for a wide range of regional and structural parameters.

Consumer devices such as washing machines are too small to make any reasonable headway with demand side management. Devices integrated into the VPP have to be more flexible. This holds true for heat pumps as well as for electric boilers. And of course it’s also helpful when we can bundle together facilities with widely varying degrees of flexibility.

Can you already identify the requirements that absolutely have to be met?

The situation in the Rheintal region is a favorable one in many ways, both in terms of the region’s socio‑cultural characteristics as well as the structure of the energy sources and energy industry. We also have a strong implementation-focused sponsor in illwerke vkw, which has helped to bring other implementation-minded partners on board.

At the same time, we must have enough users who have a certain amount of tech savvy. I don’t mean people with technical expertise, but rather those who are open to using technology in their home. Willingness to use a smart home box, for example. Many applications, such as trading of energy generated by PV facilities, are not yet economically viable in Austria right now because of legal considerations. That’s why we need other players who are interested in taking a small step back from the present and investing in the future. Rheintal’s population is very open to this.

One final important element is electromobility in the region. Integrated in the regional VPP as consumers, EV infrastructure plays a major role in letting us test ideas today that we would like to use tomorrow.

What’s next for the VPP? What role will it have in the region after the project ends in 2015?

That depends a lot on whether we can actually accomplish certain goals, such as load management in the districts. In one neighborhood, Hard, we will reach the implementation phase in the coming months. The residents there could soon enjoy lower electricity costs.

We also plan to expand the electromobility functionality and incorporate GIS data. This will make the infrastructure more attractive and play an increasingly important role in the smart regions.

In the phase right after the end of the project, we initially expect strong demand for local VPPs in residential areas. We still have some work to do to make the benefits tangible. It’s not until a second phase that demand for a regional VPP might crystallize.

More on virtual power plants

Energetic about virtual power plants? Download a free copy of the analyst white paper “A new generation of Virtual Power Plants”.

Enjoy an expert´s report of Smart City Rheintal (Austria) from Prof. Joerg Petrasch´s perspective.

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