SunCEC2007 Day 3: Green Keynote
Surely “Redshift” was the most important topic, but energy efficient computing was an almost equally important topic throughout all keynotes of the CEC. There was even a keynote presentation dedicated to this topic. The keynote presentation of Dave Douglas wasn´t the highlight of the conference, but it was a good one and gave me some stuff to think about. You can think about Germany as you want, but most of the stuff green IT tries to discuss is an rather old topic over here. Albeit the “Energieeinsparverordnung” (a typical german word, you can translate it with “Energy saving ordinance”, i will shorten it with EnEV from now on) is primary in discussion for habitated buildings, you can get some ideas for datacenters. One of the things discussed here in germany is the Primary energy factor (Primärenergiefactor). This is a really interesting number. The primary energy factor helps you to know how much primary energy you have to spend to get a certain amount of energy, as you have to produce the energy, converting it for transportation and transporting it. For example the EnEV mandates a factor of 1.1 for oil and or gas, but a factor of 3 for electrical power. Thus for every 1 kilowatt hour you have to invest 3 kilowatt/hour only to deliver it in you premise. For every 1 kilowatts/hour equivalent of gas or oil, you have only to invest 1.1 kwh of power to get it to your premise. This numbers are only valid for the energy mix in germany. A country with mor nuclear energy or renewable energy would have smaller factor, a country with more coal power plants would have a vastly higher factor than 3. This primary energy consumption is the relevant number, when you talk about the carbondioxide footprint. Okay, you can´t run a server on natural gas. So you have to produce power out of it. The efficiency of this process is around 30 to 35% electric power. The rest ist disipated as heat . At first sight you would say: Nothing won. But wait: You don´t have to waste the heat. There ist a concept called trigeneration: You use the the heat from the power generation to produce cold by a gas-absorption chiller. The problem with your own power generation is the wasted heat, you need consumers for the heat. And a datacenter with the adjactent building for the administrators has exactly this need: In summer you have to provide cold to cool down your datacenter. In winter you can cool down the datacenter with the ambient air outside the building (no chillers needed) but you can use the wasted heat to provide heating to the office building. So you´ve made efficient use of the invested primary energy. The efficiency of such an process is over 80%. Now think about regenerative energy supplies. By using biodiesel or biomethane you could vastly reduce your carbondioxide footprint. I would have to calculate things, but by taking out the transportation and transformation losses out of the equation this get a economical feasable way to run your datacenter. Especially when you think about the economical lunacy to use electrical power to produce heat by this quite good radiators from Intel, IBM, AMD and to a smaller amount Sun and then cool it down by using electric power again, unconventional ways of power supply getting more and more cost effective and cost saving (As a rough guess, you need one watt to get one one watt out of your datacenter. Makes two watts. Multiply it with three. So you need 6 Watts primary energy for every watt you need for your datacenter. Maybe lunacy is not the correct word. Brainless would be more correct) To get the cycle back to the keynote of Dave Douglas. Dave is perfectly right: We have to rethink the supply of power to our datacenter as well as the way to cool our datacenter. Not only because of our environment. There are many economic reasons to get more efficientAt the end:And maybe the generators in our cellar are not expensive disaster recovery assets, perhaps they are an really valuable asset and the public power grid ist just a backup in case your generators fail.