GREEN DATA CENTER, Växjö Partners Organisation: Partner’s role: VEAB providing district cooling, responsible for the city broadband BUDGET 11 000 000 SEK Summary The Green Data Center was inaugurated October 23, 2012, and is a cooperation between Wexnet (the broadband city net owned by Växjö Energy), the City of Växjö, the County Council and companies. Instead of investing in individual server halls, they have created a common computer center - the Green Data Center, governed by Wexnet. This makes the Green Data Center a very cost efficient and modern solution, and it is estimated that each project partner has saved 340 000 € by joining the project, compared to if they would have built their own server halls. The Green Data Center is also a good example on how to take use of energy in an efficient way. Server halls generally need a lot of cooling since the servers generate a lot of surplus heat. In most cases, this is solved by electric cooling machines. However, in Växjö we have established a district cooling grid. Cold water is running through pipelines and contributes to cool down the buildings that are connected to it. The cold water is generated via an absorption process, which actually means that district heating (from biomass) is transformed to district cooling. Anyway, the Green Data Center is connected to the district cooling system and uses the returning water that has been used for the cooling of the nearby shopping center. Even if it has already been cooling the shopping center, it is still cold enough to cool down the server halls. When passing the server halls, surplus heat is transferred from the server halls to the water pipelines. The now warmer water in the pipelines can however still be used. The pipelines run beneath the nearby football field, which makes it possible to extend the football season, since frost the field will not become frosty. But it doesn’t stop there. Mounted on the roof of the Green Data Center, is a PV plant, generating electricity that is used for the pumping the water back to the absorption cooling unit. Another positive consequence of this could be that the Green Data Center contributes to the visibility of PV plants in our community, which may have the effect that the citizens will understand even more that solar energy works also in Sweden. It should be noted that the technology of transforming RES-based district heating to cooling via absorption, was originally realized in Växjö as a part of the SESAC project under the FP6Concerto initiative. So, the Green Data Center is one interesting part of the never-ending efforts in Växjö to reduce the overall energy use, reduce the electricity use and increase the use of renewable energy. It is a project that fits very well in the general Fossil Fuel Free Växjö policy. The Green Data Center has won the award for the Greenest Data Hall of Sweden 2012. Promotional sentence The Green Data Center in Växjö is a unique example on how energy can be reused for several purposes in an efficient way, creating environmental and economic benefits for all involved actors. Action plan/timeline In 2009, Wexnet realized that they needed a new server hall, and at the same time it was obvious that the City of Växjö and the County Council also needed that. The ideas of working together in one way or another started, but nothing really happened. When the district cooling system was established in the area, the final idea was born, that it was possible to take use of the district cooling to also cool the server halls. The contracts were written in December 2011, and shortly after that the construction phase started. In October 2012, the Green Data center was inaugurated. Energy and climate achievements Since the Green Data Center has not been up and running a year yet, the effects are only estimated, and they are estimated for the full use of the server halls. There are metering systems in the halls that will give detailed measurements, so that each user will pay their share of the energy costs etc. The efficiency of server halls is measured in PUE-quotas, which is the total energy use for the entire server hall divided by the energy use for the servers. For example, a PUE of 2 means that the energy used (mainly) for cooling the servers is equal to the energy used for the servers themselves. PUE can be 1.0 as best. Green Data Center has a maximum server capacity of 350 kW, and is estimated to have reached a PUE of 1.2. Available information from before this investment shows a PUE of 1.7. This means the following: Establishing a server hall with the server capacity of 350 kW and a PUE of 1.7, would need 5,212,200 kWh/year. With a realization of the Green Data Center, used to its maximum and with PUE 1.2 would instead need 3,679,200 kWh/year. This means that the total maximum reduction of electricity is 1,533,000 kWh (29 % saving). This would probably be achieved also if the efficiency measures would be carried out in several smaller server halls, but by combining them, it also generated an economic saving for all partners. This is the result that is achieved if you still use electric cooling machines. The Green Data Center is however using district cooling instead of electric cooling, which means that an even bigger amount of electricity use is avoided. If we assume that 95 % of all the remaining energy is used for cooling, this equals about 580,000 kWh that are supported by district cooling instead of electricity. The PV plant mounted on the roof of the Green Data Center is estimated to generate 17,000 kWh of electricity every year (about 7 % of all PV electricity in Växjö), which does not need to be produced elsewhere. This means that totally, Green Data Center reduces the needs for buying electricity by 2,130,000 kWh, and reduces the total energy use by 1,533,000 kWh. Calculating decreased CO2 emissions due to reduced electricity use is tricky. It depends what system boundaries you are using. The local electric mix generates about 0,015 kg CO2/kWh, which means roughly 32 tons for the whole project. At the same time, it is possible to say that the reduced need for electricity means that there is less need to produce electricity on the margin in the North European electric market. This means that coal power plants can produce less, which may emit as much as 1 kg CO2/kWh, or 2,130 tons. Depending on how you see it, the truth is probably somewhere between these figures. Beneficiaries/Target groups? Geographical scope? The Green Data Center can be used by public or private actors. A secondary beneficiary is the football club, which can use the football field in a longer period of the year. It is a bit difficult to define the geographical scope of the project – it depends where the individual server halls would otherwise be. However, with this solution, it would be considered a local project since it is depending on the availability of the district cooling grid. Innovative features to attract media About 100 delegations of visitors come to the City of Växjö every year to learn from the things that have been carried out here regarding our striving towards a fossil fuel free community. This project will be yet another success story to talk about or showcase to the visitors. Since it is a physical place it is also possible to go there, see the PV plants and talk about how the surplus energy is being used in various steps. We also believe that this can be yet another of all the actions taken place in Växjö, that can be of high interest from national and international media. It will also to a higher extent be part of our own communication material, as we continuously update it. Media is believed to find this project interesting, and will in that case, contribute to spread the experiences over the world. Social and political acceptance and sustainability of the solutions developed The project has been realized thanks to the cooperation of many local actors, from the public and private sector. We cannot really claim that the citizens have been involved in the project, but they benefit from it in a number of ways. The citizens involved in the football club, and the people who enjoy football, have the possibility to use the football field in a longer period of the year. Another important benefit for the citizens is financial. Since Wexnet is owned by Växjö Energy, which is a municipally owned company, it means that this is in the end public money that has financed the construction of the server hall. And since the creation of a common server hall for a number of different actors has turned out to be very cost efficient, it also means that the money that has been saved thanks to this instead can be used for other purposes. The organizations using the server halls pay for their use of it, which also means that the Green Data Center is self-financing, and will not disappear or shut down after a few years. Instead, it is another important part of our way towards a more sustainable energy system – in this matter; it is mostly the ecological and economic dimensions of sustainability that are addressed. Transferability/replication potential We believe that this is a project, which in many of its parts can be transferred to other parts of Europe. All over Europe, electric cooling machines are used for the cooling of different kinds of buildings. There is most likely a huge potential to take better use of the surplus energy from the cooling. And even if the temperature of the air or water is somewhat higher after cooling the first building, it should still be cold enough to provide cooling in another building. With the Green Data Center project in Växjö, we have solved this with our existing district cooling grid, which reduce the use of electricity to a minimum. We are very well aware of the fact that district cooling grids based on district heating is not possible to implement all over Europe. But the idea of taking use of the surplus energy in a more creative, smart and efficient way is definitely transferrable. No matter how you will solve this, it will generate a more efficient electricity use, and since electricity in Europe is produced from non-renewable sources to a very high extent, this is also good for the climate impact. Also, since server halls need cooling all around the year, the idea of using the warm flows from the server halls to heat a football field is also transferrable, so is the way of working, where private and public actors realize this kind of activity together. Additional information http://www.veab.se/Pages/Page.aspx?pageId=917 http://www.mynewsdesk.com/se/pressroom/vaxjoenergi-veab/pressrelease/view/wexnetbidrar-till-att-goera-vaexjoe-aennu-groenare-naer-groent-datacenter-invigs-i-vaexjoe-802384