Bosch and Ceres Power show a fuel cell based PDU prototype for data centres
Data centres are essential nowadays, given that everything is about data. However, they consume a considerable amount of power, and as such are responsible for an equally considerable amount of emissions. Alternative energy sources need to be considered in the future. At Bosch Connected World, we got a glimpse of that future when we encountered a rather special prototype.
When it comes to CO2 emissions, data centres are responsible for roughly 10 percent worldwide, according to figures quoted by Bosch on stage during the event. That’s more than for example the aviation industry. This contribution to global emissions will only increase, as we create more and more data, which als needs to be stored and processed. This increase will likely not be cancelled out by the increasing efficiency per square meter in data centres, for example with the advent and continuing rise of hyperconverged infrastructure. The growing demand for processing power will eventually result in higher energy consumption by the systems in datacenters, even though these get more and more efficient as well.
It’s quite obvious that it wouldn’t be a bad idea to look into alternative power sources for datacenters. We are not going to stop creating, storing and processing data. The big question obviously is what that should be.
Fuel cells as a possible answer
In order to come up with an answer to that big question, Bosch and Ceres Power developed a prototype of a power delivery unit (PDU) that uses fuel cells. The prototype doesn’t have a name yet, it’s being referred to als SOFC, or Solid Oxide Fuel Cell, referring to the type of fuel cell the prototype uses. As it is a prototype, the end product will not be as polished as what you can see on the picture at the top of this page. The plan now is to pilot it at the end of the year, in Bosch’s own datacenter at their R&D center in Renningen, Germany. Commercial availability won’t be before 2024.
data centres aren’t the only use case for this type of power delivery unit, we have been told. The idea is to also deploy them in residential areas and use them to power individual houses and businesses.
The concept
As already mentioned, the protoype has been developed around fuel cells, like those developed for cars, for example. Internally there are two stacks of 250 cells stacked on top of each other. These cells work according to electromechanical principles, so with an anode and cathode and an electrolyte, in the case of SOFC this is a kind of ceramic. This ensures that electrons and ions are separated from each other, after which the ions are converted into electrical power. Per stack 5 kW can be supplied, so per unit it is 10 kW. The whole has an efficiency of 60 percent, which is quite good, compared to other energy sources.
A special feature of the so-called SteelCell fuel cells from Ceres Power is that, according to Ceres Power, they are made of very common material. So there are no rare raw materials in them. This is not only better for the earth in general, it also ensures that it is relatively easy to manufacture them. After all, the raw materials are abundantly available.
Works on gas or hydrogen
SOFCs can also use different types of gases to generate electricity, such as natural gas and methane, but also hydrogen. Of course, natural gas, for example, contains a certain amount of CO2, but according to a Bosch spokesperson we spoke to, this is filtered in an ingenious way. The most important thing about how the gas is used, is that it is not burned, so nothing can get into the air that way.
Of course, hydrogen is the best fuel for SOFCs in the long run, because that produces CO2 emissions of 0 g/Wh. However, hydrogen does not naturally occur on earth. H2 must first be extracted from H2O. This also requires the necessary energy. If that energy doesn’t come from clean sources, it won’t be of much use, of course. The question is when guarantees can be given on this point.
Realistically speaking, gas is currently the most obvious fuel for SOFCs. This can already lead to a serious reduction in CO2 emissions, according to Bosch. Up to 40 per cent is possible, although it should be noted that this may vary from country to country/area to area. If you look, for example, at a country like Norway, where virtually all energy is derived from hydropower plants, then it doesn’t make sense. Or France, where 80 percent of the energy comes from nuclear power stations. However, in Germany, for example, this 40 percent does come into sight.
Every rack an SOFC companion?
Whatever the eventual reduction in CO2, SOFC-based devices such as these must of course also be practical. In the case of data centres, there are certainly still some challenges. The first and most obvious one is that you will need one SOFC per full rack, of course without the shiny exterior, hip screen and other obvious stage decorations. It will also be a little smaller than it is now, about the same size as a standard rack in a datacenter. That means every rack needs an extra rack-sized SOFC to keep it working.
That’s a considerable investment, we can only assume, even though we have no idea yet what the price for one of them is going to be. Given the relatively straightforward materials that are used, it might not be too bad, although significant R&D investments will have been made. The companies behind these investments (in this case Bosch and Ceres Power) will want to see a certain return on them, obviously.
Unwanted guests: heat and gas
As far as we are concerned, however, a bigger problem than the costs is that gas is not necessarily a desired gas in many data centres. That infrastructure also needs to be built, whether you’re going to use natural gas as a fuel or hydrogen. Besides that, SOFCs also produces a lot of heat. The process only works optimally at temperatures between 800 and 1000 degrees Celsius. And heat is something you want as little of in a data centre as possible.
A spokesperson for Bosch we spoke to does have a solution for the latter problem though. If you place the SOFC on top of the rack it is powering, the heat can be removed relatively easily, because the fuel cells are already high up in the room anyway. It also immediately solves the space problem that you would potentially get if you had to have an SOFC device of approximately the same size as a full-size rack.
Smart cells
When we talk about the potential of fuel cells, you might be inclined to talk only about the way they generate the energy. However, in the case of this product from Bosch and Ceres Power, there is an additional dimension that is important, namely the distribution of the energy generated, in the case of a data centre between the racks there. The device is shown on Bosch Connected World with a reason, where everything is about IoT and smart ways to connect components to each other.
The idea behind linking the individual SOFC-based PDUs is that this makes it possible to do things such as load balancing and fail-over. Not every rack will be full and/or have the same energy requirements, so one PDU will have a surplus, while the other will on the limit. In order to avoid having to add new ones unnecessarily, they can balance their loads amongst each other without human intervention. Also, if one fails, others can step in and make sure energy requirements are met.
Are fuel cells the future for data centres?
The big question is, of course, whether we have seen the future of energy supply for data centres here. As already mentioned, there are hurdles to be taken before it becomes really interesting as far as we are concerned. On the other hand, it is a good sign that the SOFCs are so (relatively) easy to produce, as there will be quite a lot of demand from the market, should it catch on.
A hybrid energy supply certainly seems to us to be a possibility, in which old and new ways of generating the required power are available next to each other in a data centre, perhaps linked to refresh cycles for example. In any case, we will continue to monitor this and are very curious about the first tests of this, for example in Bosch’s own data centre.
