2. Planning and building phase of the testing environment

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1 Building-specific energy production, new concepts in local energy distribution network Klaus Känsälä Senior Scientist Technical Reasearch Centre of Finland Finland Summary Building-specific energy production solutions are becoming more common in the near future. This allows the possessor of real estate to decide whether to use the energy production for transportation in addition to living, or sell it to the electricity distribution network. VTT has built an energy self-sufficient test apartment in Oulu for the research and development of building-specific energy production. The research environment, connected to the electricity distribution network, produces the energy required for living and motoring with its own solar and wind power. Keywords: smart grid, solar power, wind power, local power distribution, in-house power plant 1. Introduction There is plenty of information available about small power plants and lots of vendors are selling their products with great enthusiasm about the quality and high power output. However, reliable independent information is harder to get. This information is vital when calculations about investments and payback times are made. Also verification of simulation models may benefit from a real production data collected from a real production site. For these reasons VTT decided to set up a full scale testing environment for solar and wind energy production. The main research themes were allocated as follows: Establishing a in-house power plan on existing VTT premises, planning and building, practical issues related to licences and project management Integration of different components together, control and data collection including database, mainframe, user interfaces and internet connectivity Mobility; E-car, charging & discharging control, wireless monitoring of vehicle parameters Apartment: renovation of VTT janitors apartment to be used as living lab, with intelligent lighting and graphical user interfaces Smart Grid: Smart power management with remote control of devices and ability to sell & buy energy from network In the following chapters these themes will be described in more detail. 2. Planning and building phase of the testing environment The first task was to define what kind of components would be implemented to the test site: after

2 an intensive planning period the following main components were introduced: wind power plant: big enough to supply at least one house/apartment solar power plant: also big enough for one house/apartment battery back-up for storage of energy E-car to study energy consumption for basic transportation advanced control, monitoring and measurement for the database (to be used in further analysis of the system ) After the basic definition, core planning was started with extended project group consisting of architect, construction designer, estate owner and technical support team from VTT. Since the goal was to place the power plant on the existing building the main problems to be solved were constructional. The load caused by the solar panels and windmill limited the assembly to few possible places. The solar panels need to be facing south and they must be installed to a certain angle to get the optimal amount of sun radiation. Thus only one side of the roof was found to be feasible. The roof was made of wooden board structure covered with roofing felt. The assembly rails of the solar cell were fixed on the roof without puncturing the surface. The electrical cables were brought through the ceiling with special ducts in order to prevent leaks. The biggest problem was to find a solid place for the windmill. Finally the best option was to mount the windmill steel platform on the top of the elevator shaft. Some reinforcing work was necessary before the final erection of the windmill could take place (see Fig. 1 and 2). Figure 1Molding the steel frame Figure 2 Reinforcing the shaft The total assembly of the roof was completed in November The main milestones in the assembly process are listed below: Milestones for the testing environment building project: Core Planning Applying licences Quotes for windmill &Solar systems Quotes for subcontracting Starting the preparatory work (construction & electrical) Assembly for Windmill & Solar November 2011 Renovation of test apartment November 2011-March 2012

3 Test & production December 2011 Figure 3 Final rooftop assembly ready The hub height of the windmill is 29,7 meters, steel mast rises 9 meters from the roof and the total weight of the structure is about 350 kg. 3. Integration of the system The integration phase took place after the hardware components were installed. Integration is very important because communication and control would not be possible without it. However there are no common standards with communication specification and therefore manufacturers have applied their own protocols and interfaces. This was the starting point in VTT s system. Major components to be integrated were solar panel power inverter, windmill control, weather station, E- car, E-car loading system, lighting system for the apartment and 3-phase main inverter. The system included numerous measurement devices and control switches as well. The control system is based on Linux-mainframe computer which has got the database and user interfaces for the main control of the system. This mainframe must have access to all parts of the system. System components are distributed to different parts of VTT building from roof to basement. The backbone of the communication network is Ethernet, but RS485, RS232, CAN-bus, USB, WiFi and some other product specific solutions are also being used. The control system stores every minute all essential parameters of the system to the database. These values are used for verification of system performance, energy efficiency, investment calculations and simulation verifications. For instance solar power production data can be compared against the production of windmill power production, Weather information is also available from a Vaisala weather station on the same building. The goal of the integration was to hide this complicated system from the end user and make the control of the system easy. The control user interface is graphical and it is using HTML5. This makes it versatile because user can access it by multiple devices (PDA s) using browser and internet access. The user interface provides information of the system status and the energy consumption. It takes care of the energy distribution and power management by controlling the power plant and energy storage. With it the user can also buy or sell energy to the network. The system gives protection against blackouts by automatically switching to battery supply. With this the apartment can provide energy for normal living during several days.

4 Figure 4 Part of the control room components: front solar inverter from Vacon. Figure 5 E-car and loading station. 4. Mobility issues Mobility is an important part of living. VTT test system includes an E-car with necessary loading stations. E-car operates most of the time with solar and wind power. A special reservation system controls the energy consumption of the car and ensures that there is enough energy for the trip. The intelligent charging system takes care of fast charging of the car. The wireless monitoring system reads status information from the car and sends this to the main database. The energy efficiency of the E-car changes depending on the driving environment, the car can store braking energy back to the battery thus inside town the traveling distance may increase. On a cold weather the heating takes lots of the battery capacity reducing the available driving distance.

5 5. VTT s apartment: living lab VTT had a apartment which was originally built for the janitor. Since many years there has not been janitor s in VTT and the apartment has been rented for VTT s visiting researchers. During the project this apartment was completely renovated to be used as living lab, with intelligent lighting and energy management systems. The apartment has got two bedrooms, kitchen, living room, bathroom and sauna. The area of the apartment is 77 m 2. The biggest changes were made to the lighting system. The former system was based on light bulbs and it was completely replaced by led based illumination. The new system was designed based on instructions and recommendations about home lighting. Total power consumption was reduced from the former 3500 Watts to 300 Watts peak power with improved light intensity. In addition to this new led system is using 24V DC power and therefore it can operated directly lead acid battery power source. This arrangement has got two main benefits, it is easy to connect solar cells to the system and in case of blackout DC power from battery keep the lighting on. The control system of the lighting operates also on 24V DC current. It is based on CAN-bus and has flexible programmable functionalities: wireless user interface, automatic operation based on presence detection, timers, automatic dimming, day-, evening- and night status etc. The power consumption of the LED s is measured and send to the database. The next biggest change was made to the electrical system of the flat. The fuse panel was replaced with intelligent one providing remote controllable on/off switches for the household electronics including kitchen and bathroom. The fuse panel has now an Ethernet connection to the mainframe computer. This makes it possible to measure and control and cut down the energy consumption of the apartment. The information collected from the apartment can be used for instance to study the consumption profiles and differences between different users. Ass well it will be used to analyse the energy balance between power plant E-car and apartment. Figure 6 VTT s test apartment. 6. Smart Grid Smart Grid is currently very popular research topic. It can be defined in the following way: Smart grid is a next generation electric power network that incorporates information and telecommunication technologies into an electric power network that enables real time, two-way communication exchange to power suppliers, the electric power markets, and consumers

6 The existing technology used in power distribution networks creates several problems and challenges which need to be tackled before real applications can spread to the market: Applying distributed energy sources to current electricity production in large scale Providing reliable and smooth demand-response control methods Improvements required in energy storage technology (unit price too high) New automation in energy delivery networks needed Controlling the Smart Grid requires new communication system with features that has not been implemented anywhere so far Amount of data will be huge Smart Grid enables new business models for different players: a whole set of totally new services may appear Electricity and energy networks are critical infrastructures; no compromises allowed in security and reliability. VTT s testing environment will serve also as a tes tbed for Smart Grid research projects. The next steps include database management and user access to the system in order to let the project partners to get to the system for testing and data analysis. 7. Project Status The roof of VTT s research environment holds a 5.5 kilowatt wind power plant and around 20 square metres of solar cells generating 4 kilowatts. Together, they produce enough electricity for living and running an electric car. The test apartment is used as accommodation for visiting scientists, and it is located at VTT Oulu premises. The apartment is equipped with normal, energy-saving household appliances and other equipment. Lighting is optimised, based on a low-voltage network using 24 VDC. The resident can affect the energy consumption through his or her choices. VTT is collecting data of the apartment s consumption and production and the choices made by the residents in its database. Consumption data is stored in the database at one-minute intervals. VTT s research scientists utilise the data in designing future forms of living and sizing the new systems. The test apartment helps VTT to study what are the benefits of energy self-sufficient living for the consumer. At the moment the system is running and in full use. At the moment the energy production has been lower than expected: Solar Energy (February 2012-November 2012) 2959 kwh Windmill (December November 2012) 1783 kwh Solar panels did not produce any energy in December and January. The solar inverter was optimised for 10 kw panel supply. For this reason another 4 kw set of panels will be added during the spring. The control system of the solar inverter did also broke down in June and one month s production was lost. Windmill was stopped for maintenance for two months in the spring. The steel pipe was suffering of resonance vibrations and tis problem was fixed by adding a stabilising mass to the pipe. On December 2012 the windmill suffered some damages by ice packing to the rotating blades. 8. Future Steps In the future, the consumer will monitor and control the electricity consumption of his or her living and transportation, and can even sell electricity to the network. This is made possible by the development work on intelligent electricity networks, improving the efficiency, flexibility and dynamism of old-fashioned electricity distribution systems. VTT is using the energy self-sufficient apartment to study, for example, how much the resident can reduce the energy consumption peaks and how much the energy consumed by living can be

7 reduced. In-house local power plants could be located in, for example, office buildings, commercial buildings and residential buildings. With advanced control and monitoring system the consumption and production can be locally justified and this local control will be essential part of future energy distribution network. 9. References 1. Solar inverters VACON 8000 SOLAR standalone inverter Vacon.: 2. D3 Suomen rakentamismääräyskokoelma Rakennusten energiatehokkuus. Määräykset ja ohjeet Ympäristöministeriö, Rakennetun ympäristön osasto: 3. Produktinformation. Hannevind Vindkraft AB Tuulivoima. Motiva Huhtinen, Markku Korhonen, Risto Pimiä, Tuomo Urpalainen, Samu Voimalaitostekniikka. Tampere: Juvenes Print.