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Published on November 4th, 2015 | by Guest Contributor


Three Ways Data Centers Can Use Solar Energy

November 4th, 2015 by  

Flexenclosure-eCentre-Mozambique-Vodacom-1038x576Originally published on the ECOReport.
By Srikanth Murugan

“Energy efficiency” is undoubtedly a watchword in the telecoms and data center industry. Many ICT companies now have corporate social responsibility (CSR) programs focused specifically on reducing their data centers’ carbon footprints and every data center operator wants to be able to promote the fact that their data center is green. Here are three ways to use solar energy for data centers.

Of course there are a number of ways of achieving this, including optimizing the floor plan, the insulation and cooling technologies, the data center infrastructure management systems and of course, using clean renewable energy sources such as wind and solar power. And it is the solar element that I want to talk a little more about here.

1. Buying solar power from a nearby utility

Some large data center operators, such as Google, have made long-term financial commitments to buying renewable energy from green energy providers in the same grid regions as their data centers.

Regardless of whether local utility companies can provide the data center’s entire power requirement from renewable sources, it is certainly a step in the right direction as it not only reduces the data center’s carbon footprint but also supports long-term investment in solar power generation by the utility company – a win for all concerned.

2. Building a local solar farm as a partial energy source

Unfortunately there are still relatively few electricity providers around the world that generate significant quantities of solar power, so depending on where your data center is located, option one (above) may actually not be an option at all.

However, that does not mean that solar power cannot still be used. On the contrary, building a smaller, local solar farm as a dedicated partial energy source can be a viable option for some data center operators. As the solar energy produced here is always consumed directly in the data center, there is no need for added battery storage or more frequent battery replacement. This significantly improves the business case to build a local solar farm, and it improves yet further in areas where either the price of grid power is high or the grid is unreliable, resulting in significant use of costly diesel gensets in order to keep the data center live.

An interesting development here is the introduction of DC-powered servers. This will eliminate the need to convert solar-generated DC power to the AC power used by most servers today and thus reduce both initial capital expenditure as well as on-going DC to AC power conversion losses in the system.

This said, even if the data center itself is optimized to use DC power, the amount of real estate available for solar panels at many data center sites will still likely be a limiting factor and the solar farm may only be able to generate a small percentage of the total energy required. Even so, the use of solar power generated in this way will still make an extremely valuable contribution to an operator’s green CSR story and in areas where energy costs are particularly high the business case for a small local solar farm can be very strong. This is particularly true for a prefabricated data center (such as Flexenclosure’s eCentre) that can be optimized to host solar panels and effectively harvest solar energy.

3. Building a local solar farm as the primary energy source

As mentioned above, available land for the installation of solar panels is likely to be a significant limiting factor even when establishing a local solar farm as a partial energy source. This challenge then grows if it is to be used as the primary energy source. In recent years, solar panel efficiency has improved significantly, but even in tropical conditions with very good solar insolation you would still need (roughly) a 39kW solar array – nearly 260 sqm – to support a single IT rack with a 5kW load. So even for a relatively small data center with only 10 racks, you would need an area of 2,600 sqm just for solar panels.

Even if the real estate was available to install a large enough solar array, solar energy is of course only available to be collected for a limited number of hours per day (if at all on cloudy days). For the remaining time the power would need to be stored in potentially enormous and extremely costly battery banks – a capital expenditure pill that most data center operators would simply not swallow.

Added to this, in typical data centers the battery is always kept in float charge, meaning on standby and used only for emergency backup purposes. But batteries that are used in solar applications are regularly charged and discharged. This will reduce their lifetime and they would need to be replaced every three to five years depending on the type of battery used – an operating expenditure issue to add to the capital expenditure issue above.

So at first glance it looks as if using solar energy as the primary source of power for a data center is simply not viable – at least not with the technology available today.

However, there is an exception… a positive business case can be made for solar as the primary energy source for remote micro data centers in areas where there is no electricity grid and diesel power is the only option. This emerging market can be effectively served by hybrid solar power systems (such as Flexenclosure’s eSite).

A solar future

As solar technology continues to be improved; battery efficiency and lifetime increase; and component prices continue to drop, the overall business case for solar powered data centers will undoubtedly strengthen over time. Notwithstanding the options of buying in solar-generated power from a local provider or establishing a small solar farm as a partial energy source, “solar” and “data center” are not truly synonymous today and there are many other ways to make your data center “green” without needing to use solar power. But times are changing and solar energy will undoubtedly have a central role in many data centers in the not too distant future.

Srikanth Murugan is Global Director Sales Engineering at Flexenclosure, a designer and manufacturer of prefabricated data centre buildings and intelligent power management systems for the ICT industry. He has spent nearly two decades working in the telecommunications industry around the world. He is particularly experienced in pre-sales and project management, and balances keen business insight with deep technical expertise. For the last three years. Mr. Murugan has led the Sales Engineering function at Flexenclosure, responsible for designing bespoke customer data centre solutions. See www.flexenclosure.com.

Photo Credit: Flexenclosure-eCentre-Mozambique-Vodacom – Courtesy Flexenclosure

Reprinted with permission.


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  • Ronald Brakels

    And putting PV on the roof also helps with keeping the place cool, giving an additional benefit.

  • sjc_1

    SOFCs like Bloom can create electricity and heat from cheap natural gas, synthetic natural gas can be created from biomass. The heat is used in absorption cooling for the data center.

    • Marion Meads

      Don’t forget that the Bloom Box can use biogas as well.

      • bink

        at what cost ?

        • Ronald Brakels

          $6.71 USD/MMBtu for biogass in Europe currently.

  • Omega Centauri

    Might there be a case for self-consumption plus modest battery storage? By this I mean enough battery capacity (and PV overbuild to charge it) so that after a sunny day,
    grid power is not needed for a few hours -long enough to get pass peak time of use rates. For example PG&Es peak rate extends to 9PM, a few hours worth of storage would allow PV plus batteries to cover the entire daylight plus early evening peak rate.
    The utility ought to be willing to accomodate such an arrangement, as it works to cut off the head of the “duck”. It seems to me that positive payback for such limited storage will come much sooner than payback for overnight storage.

  • JamesWimberley

    To prevent the Cloud from gobbling up the whole electricity supply, and put the IT industry on a sustainable path, the rate of increase in power efficiency has to be greater than the rate of increase in demand. The arrival of server hardware based on low-consumption ARM processors is putting Intel under pressure on efficiency and not only power, so there are signs of hope.

    • Passer-by

      There is an opinion that yes ARM is more efficient than Atom, or now CoreM or Skylake at no or minimal load, but at high loads Atom will manage power consumptionn better. Actually it possibly end up with less power consumption because of it higher computing power.

      • JamesWimberley

        ARM’s progress on computing power, always staying within the frugal power envelope imposed by a smartphone battery, looks steadier to me than Intel’s progress on cutting the power draw of its beefy processors. Intel has managed to design adequate smartphone SOCs, but even selling at a large loss these have captured an insignificant share of the market. Holding on to its dominance of the server market is a survival matter for Intel, and its efforts there are probably more serious.

        • Passer-by

          They both have their merits. ARM is for embedded systems and mobile devices. No notebook has it for processor. ARM is 2-3 times cheaper, but their power consumption is about the same now with Skylake. It is like GPU. You can use them for general computations and if a task fits, they outperform CPU. But they lack some flexibility and can not be used for many task. ARM is good for not heavy workloads like websites, but with more or less the same power consumptions it is more a question of the price.

          • madflower

            ARM is a general purpose computer. You can do everything on ARM that you can on Intel provided the OS supports it. Most major versions of linux support it.

            Most notebooks don’t use ARM, but most tablets do. There are a few ARM based notebooks on the market.

            ARM is not like a GPU, it usually has an embedded GPU. It does have distinct units or engines specifically for things like ssl, that offload from the main CPU core.

            2 billion ARM CPUs are sold every year. Intel isn’t close.
            However, a lot of ARM processors are actually micro controllers used in embedded applications like appliances, automobiles and industrial controls.

            There are numerous companies that license the same ARM design then customize it for their own purpose. They also can contribute to the core ARM design.

            ARM doesn’t support some of the speed, but it is good for massively parallel applications like web servers. They put 48 cores on a single chip. Which Intel -can- do but they usually have overheating problems.

            Intel also has a huge problem with legacy overhead. They have been trying to get away from it for years. They have been baby stepping away from the classic x86 architecture for about 2 decades.

  • Marion Meads

    “But batteries that are used in solar applications are regularly charged
    and discharged. This will reduce their lifetime and they would need to
    be replaced every three to five years depending on the type of battery

    It depends upon the energy capacity of the batteries. Bigger ones will not undergo deep cycling of charging and discharging and thus their life is prolonged. Some flow batteries are cheap and have way longer life than 10 years.

    But of course, no batteries are big enough if you remain off-grid. There should be a reliable back up generator, especially if you have a data center. We require our colocation facility to have at least a 14 day backup generator.

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