Thursday, May 30, 2013

Impressions from e-Energy 2013

On May 22th, 23rd and 24th we attended the fourth International Conference on Future Energy Systems (ACM e-Energy) in Berkeley, California.

The conference was open by the beautiful keynote talk held by Dr. Jeffrey Taft from Cisco. It gave to the audience a complete understanding of current trends in the smart grid.
In their vision, the smart grid is a network combining 4 layers, the energy production and distribution, the market, the information layer and the social network (yes social networks). In the last years the progressive installation of renewable energy generators made the grid more and more unstable, as consequence of the sources exploited. To realize the vision of smart grid, it is necessary to provide the means for applications rather than looking for a killer application that justifies the need of such a change. Indeed innovation in the greed should foster developers, which would create a positive feedback to promote more and more innovation on the system. Basically, the stakeholders are looking for a system that can let them implement closed-loop controllers and attach them to the grid in a plug&play manner. This raises various concerns. The presenter mentioned data interoperability issues in the grid and showed the need of a multilayer network architecture able to tackle the complexity of the system.
In fact there is ongoing research in this direction (e.g. CoAP) but current solutions lack in scalability and still require high degree of mantainability. A multilayer network architecture should be deployed to give stakeholders the possibility to work at different abstraction levels and implement controllers as optimization problems broke down from the overall goal of ensuring a certain degree of reliability and stability.
In this model, the lower levels consist of components exploiting real-time delivery of information to manage safety-critical aspects. In the upper levels, the information is processed (e.g. to produce analytics) and delayed so that decision makers (both human and automatic) can exploit it to optimize specific goal functions.

The other two keynote talks seemed to converge to the need of a distribution network closer to the internet. However, the existing infrastructure will unlikely be replaced with a new smart grid. We will most likely assist to the progressive replacement of crucial components with new ones. This will certainly bring high risk of failure into the system.
On the other hand, developing countries will be able to directly install innovative components into their energy systems, which will let them experiment new technologies and enable them to catch developed countries up. In the third keynote held by Arun Majumdar, the similarities with the internet network are even more evident. He clearly mention the need for something like power routers that would transform a strictly hierarchical network to a more flexible one. Current challenges and trends are very well presented by the speaker, altough for obvious reasons, ongoing solutions studied at Google are not even introduced to the audience.

  1. Storage integration
    The first two papers dealt with the problem of mananging storage so as to reduce peak periods and optimize running costs of devices. The following two were as much interesting, as they proposed the use of batteries to reduce outages and improve power qualities in areas were energy provisioning is particularly unreliable. The third paper was in particular interesting, as it proposed to use a ups on a device-level, so that the ac-dc conversion losses can be minimized for consumer eletronics devices, and the problem of managing storage capabilities can be distributed.
  2. Measurements and their use
    The second session concerned the exploitation of consumption data to infer further information. The first paper presented an approach to demand forecasting, although they only used a feature for their predictor, which definetely makes the solution completely context-less. The second paper proposed a set of requirements and a cloud-based architecture very similar to the one proposed in our paper "Integrating households into the smart grid". However, they used a tailored protocol and data representation and did not consider scalability issues that might arise from this approach. The third paper presented a very interesting approach to infer household and inhabitants characteristics out of metering data. Finally the last paper proposed the use of ethnografy and other kind of studies used in humanities to enrich the data collected through sensor networks, so as to produce much more descriptive representations of inhabitants activities that can be better analyzed during studies promoting energy conservation.
  3. Distributed control
    The third session mostly included papers dealing with distributed vehicle charging.
  4. Data center energy management
    The papers of this session were related to energy-efficient data centres. In particular, the third paper dealt with the efficiency of ethernet interfaces.
  5. Energy efficient networking and network inference
    The first paper presented an approach to infer the topology of the distribution network out of time series collected on meters. The second paper introduced the concept of hierarchical state estimation in the energy grid and reported possible ways of detecting malicious attacks to this system. The following two papers dealt respectively with the performance of network interfaces and the TCP protocol.
  6. Smart homes and buildingsThis session was definetely the last but not the least interesting. In the first paper an implementation of supervised random forest classifier was used to detect the device type connected to a sensing unit, as well as its operational state. In the third paper, a kinect interface was used to determine the amount of clothing weared by people. A voting mechanism was used as comfort feedback for the heating controller of the room. The final goal will be suggesting to the user to wear a coat when he start feeling cold and giving lower rates to the system. The last paper of the session concerned activity recognition in office spaces. In the study they used finite state machines to describe the state logic of the environment. However, this raised an interesting discussion on the need of domain expertise to specify the transitions. Therefore they decided to also use a LHMMs (Layered Hidden Markov Models) and learn the transition probabilities from a dataset. This model is then used to manage the light dimming and status. They showed remarkable savings of energy using this method.
  • Poster and Demo session
    • The poster and demo session was no less interesting than the papers. Among those the work of University of Southampton should be mentioned. Basically, they use a HMM to build a model of inhabitants out of the events created in the household. Beside the HMMs they compared various algorithms, and showed HMM outperforming all of them. In fact it was very interesting to discuss the concept drift issue with classical data stream mining algorithms, as well as to the necessity of binding detected events to the inhabitant who actually performed it in order to improve the model.

  • Panel discussionThe panel discussion was brought up a general discussion and interesting questions summarizing current trends and challenges in:
    • Fossil fuels are not sustainable and we will have to cope with this problem already now, as climate change is evident.
    • Renewable energy are destabilizing the energy grid, due to the volatile sources exploited for the production.
    • Institution will play a crucial role: incentives will have drive customers to more efficient products and technologies, essential role is played by research and development activities.
    • We will move to a situation where users are empowered with energy awareness and their decision making will be enriched by pervasive components, tracking their daily life activities and assisting them in reducing the footprint.
    • Energy will have to flow in a bidirectional way and information regarding energy price will have to be available to users to get them into the loop.

Wednesday, May 22, 2013

Integrating Households into the Smart Grid

On May 20th 2013 we attended the first IEEE Workshop on Modeling and Simulation of Cyber-Physical Energy Systems. The workshop was collocated with the fourth International Conference on Future Energy Systems (ACM e-Energy), to be held in Berkeley on May 22th, 23th and 24rd.

The topics presented were very variegated. In the first session the papers were mostly concerning simulations of building or system-scale aspects in the grid (distribution, market, power flow modeling). The opening presentation was given by Kyle Anderson from Stanford University, presenting the GridSpice simulator, a cloud-based simulation tool which relies on multiple agents to run different existing simulation tools (MATPOWER and GridLab-D) and mantain the overall simulation consistence with a central coordinator. It also provides a RESTful interface to access the simulation, so that it can be integrated in third-part applications.

In the second session more applied and variegated aspects were presented.
We opened this session with the paper "Integrating Households into the Smart Grid". It deals with the problem of device and data interoperability created by the highly heterogeneous ecosystem of digital devices present in homes. In the paper we discuss requirements that should be addressed when copying with such a complex network. We show that an architecture based on REST webservices and linked data streams would be able to tackle this complexity. Applications can access the data through a uniform interface consisting in specific APIs and standardized query languages, as well as agreed ontologies for the specific use case.

The following presentation surveyed existing ontologies for smart home and smart energy systems and was held by Marco Grassi from Università Politecnica delle Marche. This completed the device and data interoperability issues and gave the audience a complete overview of this side of the smart grid.
The following presentations dealt with security aspects of the grid, such as detecting spoofing attacks on power grid GPS sensors. Also, multi-agent algorithms and control schemes were proposed for various aspects involving cyber-physical energy systems (i.e., resource bargaining, model-predictive control, coordination of power flow controllers).


Monday, May 13, 2013

New Photovoltaic Power Plant

The smart micro grid lab has the major aim to provide the capability to pursue research and to teach students. To meet these requirements the lab is designed to establish a virtual common house with renewable energy sources and the ability to perform energy management tasks.
PV modules on the roof of the
Lakeside Science and Technology Park, Klagenfurt, Austria
In detail, the lab finished the first construction phase and is now equipped with a photovoltaic power (PV) plant built up by the company Energetica. The PV has a capacity of 4.8kW and has the ability to act in the grid-connected mode, where energy can be produced, consumed and be fed into the grid and the island-mode, where the lab can be disconnected from the grid and be powered by the PV power plant and a battery buffering systems. To be able to simulate the lab in the grid-connected and the island-mode, the lab has the ability to switch from one mode to the next mode by demand. The concrete technical equipment is based on a Backup System of SMA, which delivers all necessary hardware to switch from island to grid-connected mode and to operate the PV power plant with the PV modules and the batteries.
PV performance over 3 days for cloudy and sunny days
In future, the smart micro grid lab will also be equipped with common household appliances which can be controlled and measured according to the consumed power.  With the ability to store and to generate energy, to connect the lab to and off the grid and to measure and to control appliances, the lab will have the ability to test and to develop algorithms and techniques to improve energy management systems of the future.

Energetica - energetica Energietechnik GmbH
SMA - SMA Solar Technology AG

Monday, May 6, 2013

The Smart Grid Need

Touching video about the transformation of our energy system into a smart grid:

 "All over the world countries are pursuing grid modernization for the benefits it provides to their environment, their economy and their energy security."

"By modernizing the grid we can squeeze much more power out of the system than we already have and that means saving tens of billions of dollars in power plants and power lines that we do not have to build."