Operators will increasingly need to juggle various sustainability strategies because energy efficiency trade-offs cannot be made between investing in renewables like photovoltaic ( PV ) for lowering emissions and managing higher densities at rack level.
Investments in renewable energy alone, according to Steve Campbell- Ferguson, global design lead at NTT Global Data Centers, wo n’t lessen the need to push rack densities or invest in more effective cooling.
” In my role, the IT is essentially a large energy heater.” In terms of the connection to solar, Campbell- Ferguson notes that a more deep electric heater undoubtedly introduces additional issues.
Squaring the circle will still require taking a step back and examining the state of power procurement, as well as making additional investments in additional energy-efficient technology, such as liquid-cooled racks and whether immersive or direct-to-chip designs are usually required. This is particularly true given that liquid cooling may afterwards be advantageous for different ambitious projects, like district heating.
Considerations are numerous.
For efficiency and cost-effective moves, such as raising ambient temperatures, Bruno Berti, older vice-president of global product management at NTT Global Data Centers, concurs that high-density heat exchange and advanced cooling will also be necessary. For instance, he notes that while higher densities at the rack may require less space, on-site renewable requires more space.
NTT’s greater focus is on developing its power procurement ecosystem to meet renewables demand for a variety of reasons, as opposed to spending more directly on renewable.
According to Berti,” Increasing power demand is actually just causing us to accelerate buying more of those renewable sources because our commitment is to be 100 % renewable and help our clients get it because they’re demanding that as well.”
Top PV usually only provides” a little fraction” of the power required by a datacentre, according to Helen Munroe, head of environment and sustainability at Pulsant.” For an existing building retrofit, energy produced is less than can be avoided through similar investments in energy efficiency works,” she says.
On-site power generation requires close proximity to a personal wire arrangement that can be connected instantly, such as in the case of an existing solar or wind farm.
Additionally, 24x7x365 carbon-free energy ( CFE ) consumption cannot be achieved solely through PV; instead, you must combine intermittent solar and wind, battery storage, and baseload CFE sources like geothermal and nuclear. According to Munroe, this is why operators are focusing so much on power purchase agreements ( PPAs ) to fund particular renewable developments across a region or even an entire nation.
According to her,” we are also seeing innovations like” cool roof” paints and thermal cooling panels that claim to save up to three times as much energy as solar panels generate for the same area.” ” On-roof PV can play a role, but it’s small and not the most significant one right now.”
According to Computer Weekly, Uptime Intelligence’s research director of sustainability, Jay Dietrich, does not have data on how much solar the datacentre industry uses. However, research indicates that solar use is increasing, with the cost of installed capacity per kilowatt (kW ) decreasing between 2021 and 2022.
For a variety of reasons, datacentres frequently use clear or economic PPAs to match electricity use with solar power to reduce their overall carbon footprint rather than investing directly in solar. Despite rising demand and higher interest rates, he claims that datacentres are already among the top PPA buyers.
However, Dietrich cautions that these arrangements vary greatly, are frequently extremely difficult, and involve substantial financial risks.  ,
A building will become much heavier and more susceptible to structural and fire risks if solar panels are added to a datacentre rooftop, which usually only covers 5 to 20 % of the energy demand. A “very big area of outdoor space” may be needed for a practical, cost-effective deployment because solar power densities are low and output is intermittent.
Not to mention that other “forces and factors” that can be certain to facilities, such as market forces and supply chain issues, can also affect output, which rises from zero in the morning and decreases to zero during the evening, and varies throughout the day according to cloud cover, smoke, or different factors. All of these have a low degree of predictability and usually restrict the benefits of installing any particular scientific system or infrastructure.
However, investment in renewables is still serious.
According to an Uptime analysis, several operators currently find the risks of on-site renewable deployments to be unacceptable, and this is likely to hold true for the foreseeable future. Dietrich quickly adds, however, that investing in renewable energy sources, such as solar, is still urgent for a variety of reasons unrelated to rack densities or power usage effectiveness ( PUEs ).
In order to achieve their objectives for energy demand and sustainability, datacentres, it would seem, must continue to consider all options when it comes to server room investments.
According to Dietrich, a site can run on energy produced entirely from fossil fuels while still being somewhat efficient, with an average PUE of less than 1.2 and 50 % of its IT equipment being used.
According to him,” Just because a datacenter is energy-efficient does not necessarily mean that it is low-carbon or environmentally friendly, and vice versa.” According to  ,” A facility could be operated wastefully, with great PUE, or with small regular utilisation of IT equipment, but be powered by a nearby grid that only uses wind, solar, hydropower, and geothermal generated energy.”
Meanwhile, SCC, a major UK provider of solutions, recently retrofitted 737 kW-peak (kWp ) of roof-mounted solar in its flagship Birmingham datacentre in collaboration with Conrad Energy,” who are essentially funding it,” according to Paul Southall, head of sustainability and projects at parent Rigby Group.
He confirms that the company has already set its 2050 net-zero target for 2042, but is considering combining a number of initiatives and taking into account all options in an effort to reach their goals even more quickly.
Southall adds,” Solar in the datacentre is part of that, along with commissioning and building a fresh refurbishment and disposal recycling facility off campus, and we’ve installed heat pump, trying to avoid gas.” Despite the fact that the gas deadlines were recently moved.
There are as many solar panels on the roof as possible, according to Alex Groves, net-zero lead at SCC, but there is no overspill for the grid because” 100 % of what is generated will be consumed on site.”
Groves continues,” There are at least two additional targets for different buildings, which would be installations of a related size.” Fingers crossed, and in the larger group, additional opportunities come to perhaps about five megawatts [MW].
Customers in the public sector are increasingly demanding more drastic changes to efficiency and sustainability while still being frugal and needing a higher level of resilience. Nevertheless, he says, that entails” sharing, managing, and optimizing,” as well as working to increase overall utilisation and to meet demand and sustainability targets.
” We’ve carried out projects to optimize fan use that have resulted in energy savings greater than those generated by solar panels.” According to Groves, the energy you do n’t use and are not wasted is worth much more than what you can produce with renewable energy.
Points of connection must coincide in the proper locations, and any drawbacks must be taken into account, such as the actual number of days of electricity the business building consumes. If you do not use all of the energy produced on site, even if you have a large roof for PV, the payback calculations become” a little bit controversial,” he says.
SCC is therefore continually considering how it can function more effectively and advance its “game” of energy efficiency and emissions while using less energy. ” I have a lot of aspirations. Groves says,” I’d love to install thermal, which is a much more expensive, over the parking lot.
In particular for facilities situated in areas without access to low energy use strategies like free air cooling, Uptime’s Dietrich confirms that new technologies and designs are required to raise the industry standard of efficiency “in a major way.”
To help combat the climate crisis, these innovations and the growth of carbon-free energy generation are urgently required, but they are independent of one another, he claims. ” For rack density configurations, the situation is the same.”
For higher density IT, warm and cool aisle containment must also be considered. Higher cooling system efficiencies may result from an increase in temperature variable during the heat exchange process. He notes that using these kinds of cooling systems can lower both the amount of energy used and the resulting carbon emissions.
Once more, there are n’t many, if any, shortcuts to the energy-efficient, cost-effective, lower-emissions datacenter.
