According to the US Green Building Council, the direct and indirect impact of all residential and commercial buildings account for nearly 48% of the US’s energy use and nearly 30% of its greenhouse gas emissions. In addition to dangerous carbon emissions, buildings also consume vast amounts of water (over 12% of potable water). The statistics on resource use are similar for other developed countries around the world and developing countries such as China and India are forecasted to be constructing billions of square feet over the next several decades. It’s important to begin to think about sustainable building and specifically, intelligently designed data centers, immediately.
While the ultimate goal of sustainable building is to develop structures that are carbon neutral, utilizing best practices to minimize the overall environmental impacts of site planning, water and electricity use, and raw materials expenditures would go a long way to reducing our impact on the environment. In addition, developments should attempt to maximize indoor air and environmental quality. Based on some estimates, we may be using approximately 1.25 Earths to support our current global activities. This means that it takes approximately 15 months for the Earth to replace what we use in each 12 months.
Below are some concepts that builders of data centers can use in making their projects more sustainable. We are always looking to enhance our ideas for building sustainable data centers, if you have any ideas please share them with us by contacting Sales@CoreSite.com! Not every project will be perfect, but the reduction of environmental impacts can often be made at little to no additional cost if taken into consideration early on in the design phase. It’s important to comprehensively plan and early on in the process.
Developing high-density buildings is more energy efficient than building less dense buildings. The energy efficiencies are realized with a lower ratio of walls to occupied space and essentially developing a larger building uses less resources than developing ten smaller buildings of total comparable size to the larger building. Specifically with data centers, building to a higher power density will use less building square footage (though you will still need a consistent amount of infrastructure space) and raw materials.
As discussed earlier, commercial buildings are at the root of a large percentage of today’s carbon emissions. In order to combat this, organizations can attempt to become carbon neutral. Some steps that data center companies can take to help obtain carbon neutrality are to subsidize public transportation for employees, plant trees in forests or even buy carbon offsets. While there are many carbon offset companies to choose from, we recommend trying Carbonfund.org, NativeEnergy, or TerraPass.
LEED Certification
Leadership in Energy and Environmental Design (LEED) was first introduced in the late 1990s by the US Green Building Council (USGBC) with the goal of improving the way buildings are built and reducing their environmental impact. There are four major types of LEED certification: Certified, Silver, Gold and Platinum. LEED certification can include both new and renovation projects.
Green Globes
Green Globes is a green building rating system that has gained advocates in part because it may be cheaper and easier to understand than LEED certification (even though Green Globes and LEED overlap in many of their credits). The Green Globe rating system consists of seven categories: Project Management, Site, Energy, Water, Resources and Materials, Emissions and Indoor Environment.
Commissioning a data center involves testing all energy-using systems prior to occupancy. Testing power systems to see that they work as designed before they are being used for mission-critical applications is not only a great business continuity precaution, but commissioning has also been shown to save on average a staggering 10-15% on energy future costs. This can be combined with a post-occupancy evaluation where all systems are tested to determine if they are functioning as predicted after a building is occupied. These two practices are a key way of limiting energy inefficiencies and ensuring your data center is running like it’s supposed to.
Integrating contractors is vital to green building. The process starts in the planning stages by having architects create a sustainable design and continues by letting the general contractor know what your expectations are for a green building. Before and during construction, builders are in charge of several key components to green building. The general contractor can help ensure that pollution is kept to a minimum, materials are recycled, air quality is preserved during construction and subcontractors follow green guidelines.
How cool is your roof? Approximately 1/6 of all energy used in the United States is for the cooling of buildings. In data center, that number may be as high as 2-3/6. Black and dark colored roofs significantly increase the difficulty of cooling a building. Using energy efficient roofing systems that reflect the sun’s energy before it penetrates a building can lower the temperature of a roof by as much as 50 degrees (yes, that’s right), thereby reducing the overall building temperature. A cooler temperature would reduce the burden on systems such as air conditioning units and bring down the amount of energy used to cool data centers (in addition to longer lasting roofs and lower maintenance costs). The slope of the roof is a big determinant in how reflective a cool roof needs to be, with flat roofs needing to be more reflective or have a higher percentage of the roof covered with cool roof technology (including natural vegetation). Solar panels on roofs are a great idea, especially for some locations in United States.
Some statistics suggest that as of 2006 data centers constituted approx. 1.5% of the United States’ energy demand(1). Of that demand, data center electricity can be split between power used by computers, servers, switches, etc. (together “Critical IT Load”) and power used to support the data center equipment such as cooling, lighting and electrical loss (together “Non-IT Load”).
The goal of every data center owner and manager should be to reduce the amount of Non-IT load power given the parameters and infrastructure of any existing data center. The first step to reducing the Non-IT load at a data center is to track the data center’s efficiency using metrics. Below are several metrics used today to measure data center efficiency.
Power Usage Efficiency (PUE)
PUE is probably the most commonly used metric to measure data center efficiency today. Largely supported and potentially developed by an organization called The Green Grid, PUE is a metric that takes the total power going into a data center (“Total Facility Power”), which is taken at the utility meter, divided by IT Critical Load (the sum of all RPP and PDU power, or if unavailable, the total UPS draw)(2). Simply stated, PUE reflects the ratio of Non-IT Load power to IT Critical Load power. Several forms of the equation are expressed below:
PUE numbers can essentially range from 1.0 to 5, or even higher, but more commonly range from 1.25 (best-in-class) to 3. As an example, suppose your data center had 1 MW of Total Facility Power and the total draw on your PDUs was 500 KWs (Total IT Load), then your PUE would be 2.0 (1.0/0.5). While certainly a best practice and great thing for building a sustainable business, a PUE should exclude the overall power use of alternative energy sources such as solar or wind power. The goal of PUE is to measure the data center’s efficiency, not the overall carbon footprint of the data center.
Probably the number 1 factor in determining a data center’s PUE is the amount of IT Critical Load itself. An underutilized data center is a very inefficient data center (chillers, air handling units, UPS units, and the computer equipment itself, are not efficient at 10% utilization).
DCiE is a less common metric than PUE. In fact, DCiE is simply the inverse of the PUE expressed as a percentage. The metric itself is just another way to represent PUE. DCiE numbers will range from 0 to 1, with a more common range of 33% to 80% (the higher the more efficient). While not as common as PUE, DCiE may be inherently more logical. A DCiE of 50% (a PUE of 2.0) tells you that 50% of your data center’s power is consumed by your Critical IT Load(2).
CADE is a less common metric and is more complicated than PUE and DCiE, but also more comprehensive. CADE is a metric that takes into account both facility efficiency and asset efficiency, and is more appropriately used for end users that manage their own data center as it takes into account IT equipment utilization, a dynamic that data center operators can’t control.
CADE = Facility Efficiency (FE) X Asset Efficiency (AE)
FE = Facility Energy Efficiency X Facility Utilization
Facility Energy Efficiency = ActualCritical IT Load / Total Energy Consumed (Inverse of PUE)
Facility Utilization = Actual Critical IT Load / Facility Critical IT Load Capacity
AE = IT Energy Efficiency X IT Utilization
IT Energy Efficiency = Energy Efficiency Metric for IT Equipment
IT Utilization = Average IT Equipment CPU Utilization
CADE numbers will typically range between 5 and 15 percent and can be used to manage overall data center efficiency and compare different data centers to each other(3).
Below are some downsides to looking at data center metrics alone:
When building any office space energy can be conserved by utilizing south facing windows that let in more natural sunlight, minimizing electrical use for lighting. Using awnings on these windows will keep out warmer summer sun while letting the low-angle winter sun warm the office space in the winter, thus saving on energy costs during all seasons. For data centers, it may be advisable to minimize southern exposure so to reduce the overall building’s or roof’s temperature. When indoor lighting is being installed builders should be cognizant of how much light is being provided. Many office buildings provide more artificial light than is necessary. Day lighting doesn’t apply too much to data centers as most computer rooms lack any windows, however, benefits of day lighting can still be achieved for the small office space and corridors that typically accompany data center space.
It is estimated that through the use of energy conservation the building sector alone could account for a reduction of 200 million metric tons of carbon dioxide emissions per year. The following are a couple of high-level ways in which data centers can conserve energy:
Many state and local governments and utility companies offer incentives for building efficient data centers. Often these incentives are tied to various levels of LEED certification or benchmarked against the power efficiency of traditional designs. Building an efficient data center can not only deliver significant monthly savings, but if a utility company will help offset some of the capital expenditures, then the return on investment (ROI) is that much better.
Furniture and finishes are yet another opportunity to follow green building practices. There are many opportunities to purchase products made from salvaged or reclaimed materials and certified wood products or other materials that do not contain urea-formaldehyde resins.
Integrated designing is a concept or method used by green builders. The main emphasis in this concept is to design the building or data center so that it, and its systems, can operate at maximum efficiency. When using integrated design, a builder makes design choices with the goal of minimizing the building’s need for water and electricity. Significant savings can be realized by right-sizing MEP infrastructure so that capacities aren’t stranded.
Data center lighting may account for as much as 3% or more of the data center’s total power consumption. Light emitting diodes or LEDs are a form of lighting that uses less energy than traditional lighting options and are easily dimmable and programmable. Since LEDs use less energy they also produce less heat, reducing the need for air conditioning, further reducing electricity demand. At a minimum, utilizing motion sensors on the data center floor to automatically turn off lights when technicians aren’t present is an easy way to save money.
Light pollution reduction focuses on how much light emanates from a building after nightfall. The issues with light pollution include affecting the flight of migratory birds and the lifestyle of nocturnal animals. There are two ways to reduce light pollution: building design and lighting practices. Data centers are typically designed with few windows which keeps most of the interior light inside, which is good. For those spaces whose interior lighting can be seen from the exterior it is recommended to adopt a lighting practice that reduces light by 50% from the hours of 11 PM to 5 AM. You can accomplish this by limiting the number of lights turned on at night, as well as decreasing the size of each area controlled by one switch. This allows only specific sections of a building to be lit.
When constructing a data center or other building, try using locally sourced materials or supplies. Building materials are often shipped from long distances, requiring significant energy to just deliver parts. Builders are recommended to use building materials that have been shipped from less than 500 miles. When building, find out what materials would be available from within close proximity before buying anything from a longer distance.
VOCs or Volatile Organic Compounds are found in many traditional paints and carpet materials and through the release of chemicals can significantly irritate a portion of the population. Seek out low-VOC paints and carpets as they are an easy way to make a data center less toxic and more sustainable.
Operations and maintenance practices are an integral part of maintaining a green data center. Limiting chemical fertilizers, pesticides, herbicides and other toxic substances that pose a risk to people, animals and the environment is strongly encouraged in landscape maintenance.
Rainwater runoff is a significant pollutant for the world’s oceans and rivers. Storm water meets buildings, streets and parking lots and carries oil and other pollutants from the land to water sources. Permeable paving is a concept that allows water to infiltrate or absorb directly into the ground. By designing parking lots with permeable pavement many contaminants that normally would be picked up by storm water running over a parking lot (oil, grease, etc.) would be avoided. Some ideas for permeable paving include creating retention ponds, planted ditches, porous concrete, open-jointed stone or concrete, or even grass.
It’s no secret that automobile travel and traffic is one of the largest users of energy in the world and a significant contributor to air pollution. It’s recommended to located data centers and other buildings within a quarter to half-mile of bus or rail lines. Locating data centers near rail lines not only has the added benefit of likely having fiber nearby, but it’s an excellent business continuity idea to have multiple methods of transportation available for employees. The best idea is to have your data center accessible via bicycle or foot as these methods of transportation are the least impactful on air pollution, noise pollution and lower investment in parking lots.
One way to reduce the use of water in a data center is to reuse rainwater. Installing systems on your roof to capture rainwater and then running it through filtration systems can provide significant amounts of non-potable water that can be used for toilet flushing and to replace evaporated cooling tower water. An added benefit of rainwater reuse is its effect on storm water. By harvesting a significant portion of a rainstorm, the amount of storm water runoff is reduced. This, in turn, reduces the amount of pollution caused by runoff flowing over parking lots and streets.
Use recycled materials and/or structures in building projects. The use of existing walls and roofs can not only be good for the environment when renovating an existing building, but economically efficient as well. If you use wood in your construction, seek certified wood products that are made from lumber harvested using sustainable practices. In data centers, specifically be proactive to recycle packaging from server boxes and promote electronics and wiring recycling.
When building a data center it is important to design the building size and mechanical and electrical infrastructure in harmony. Not only will right-sized systems operate at a more efficient, higher utilized level, but if you are able to reduce the size of one component without affecting the capabilities of the other components, you can save significant capital expenses. The size of the building, the amount of power and cooling should all be calculated based on legitimate estimates of need. Data centers can also benefit from modular designs. Many companies have significant growth forecasted over the next couple of years. Instead of building all future required data center space day 1, consider building out in several phases (depends on your total critical load requirements). Many data center components are very inefficient at low utilization rates.
The location of a future data center is a major decision. Not only should proximity to headquarters and power prices be taken into consideration, but so should the following attributes:
There are numerous providers of “green” or renewable power throughout the United States. Many electricity providers used by data centers offer some form of green power. Examples of green power include solar, low-impact hydro-electric, wind, geothermal and some biomass power. Green power often comes with a small premium to standard electricity.
The main concept behind thermal energy storage is using the most energy when it is cheapest or most available. Increasingly utility companies are increasing rates during peak hours. By using thermal energy storage systems a building can reduce the amount of power they need to pull from utilities during peak hours while storing energy from non-peak hours. In data centers, companies can do non-critical computing at night when energy demand is less instead of running these applications during the day when energy use is at its highest.
The urban heat-island effect refers to cities being warmer (on average it’s over 5 degrees Fahrenheit) than the surrounding area due to waste heat produced by factors such as excessive concrete, non-permeable surfaces and air conditioning exhaust. The higher the average temperature outside, the more air conditioning energy is required to be expended throughout cities, which in turn leads to more urban heat-island effect. A data center can help reduce this effect by reducing the amount of surfaces on the property that absorb heat, including cool or green roofs. Where heat-absorbing materials are needed (places such as parking lots, sidewalks, etc.) erect some form of shade that covers up to 50% of the area during mid day. Another solution is to move parking lots/garages underground.
In many parts of the United States, especially cooler and drier areas, outside air can be used to cool buildings. In these parts of the country strategically designed ventilation systems can cool a building for large parts of the year without the use of air conditioning. Air-side or water-side economization is an established data center design concept that is leading to dramatically lower PUEs in some areas of the country (“free cooling” is close to free). Buildings in windy areas of the country can also take advantage of outdoor air for cooling. By using natural breezes to push air into a building, designers can limit the amount of energy needed to power the fans that would normally be used to drive the air.
Water conservation is becoming a very big issue. Data centers can use an extraordinary amount of water, however, some concepts can help conserve water in many ways.
For general building use, “grey water” (water from sinks and showers) can be reused for flushing toilets. Furthermore, installing toilets that use less than 1.6 gallons of water per flush can save thousands of gallons of water a year (including the use of dual flush toilets). Even water-free urinals can be installed to eliminate water waste from urinals. On-site water treatment facilities can even be installed enabling recycled water use (on-site sewage treatment and rainwater reuse systems). At the very least, water landscaping only during the morning or at nighttime.
Outdoor water usage accounts for billions of gallons of water per day in the United States alone. Xeriscaping is a term used for water-conserving landscaping. By minimizing the amount of landscaping that needs water or by using drought-resistant landscaping, through the use of stone and indigenous plants, all buildings, including data center properties, can save enormous amounts of water.
(1) EPA, Environmental Protection Agency, Report to Congress on Server and Data Center Efficiency, 2007.
(2) The Green Grid Data Center Power Efficiency Metrics: PUE and DCiE, October 23, 2007.
(3) Uptime Institute Symposium: Revolutionizing Data Center Efficiency, McKinsey & Company.
