Today, we have a marked interest in renewable energy and alternative means to power our homes, businesses, and data centers. Companies, like Microsoft, Amazon, Google, and other hyperscalers, have launched initiatives to become carbon neutral within the next decade or two. Types of power generation in use today range from coal to solar, with many options in between. When a company says they are “going green,” sometimes it’s not actually clean green but rather a dirty green with a mix of offsets, renewables, coal, diesel, and actual green energy. Many renewables and other “green” energy have components that aren’t really green at all. In fact, if you could find the source of your electrons, you would find the results surprisingly dirty green!
People and companies (about 50% of us in the U.S.) have the option to purchase renewable electricity directly from power suppliers, but we all have the option of buying renewable energy certificates. Green certificates enable consumers to put money into the green supply even if they can’t consume that energy via subsidies. Some power companies have “green pricing,” which is a small premium used to facilitate energy purchases from “green” resources, as it is generally more expensive to generate electricity using renewables. But again, you can’t trace your electrons.
Renewable power sources include hydropower, wind, biomass (wood, landfill gas, municipal solid waste, biogenic), other biomass, solar (photovoltaic, solar thermal), and geothermal. According to the Energy Information Administration, as of 2019, 62.7% of U.S. power is sourced from fossil fuels with about 38.4% of that being from natural gas sources. Nuclear comprises around 19.7% of consumption, and renewables are a mere 17.5%. This begs the question, when will we get to “clean green,” and what are the obstacles to getting there?
To start, renewables like solar and wind do not provide a constant supply of current and therefore require some type of storage. As the supply changes, so does the demand. This makes it difficult to predict power usage. In fact, many data centers have large amounts of stranded power due to standby circuits and planning for peaks no matter how seldom the peaks occur. Effective management is beyond the scope of simple AI, and the target moves with load, hardware refresh cycles, and other external factors. A fluctuating supply and demand can only be met with batteries.
There are three main types of batteries: lead acid, lithium-ion, and newer sodium-ion (Natron for instance). Batteries require space to store (in some cases, air–controlled space). Lithium-ion batteries require raw material commodities, such as cobalt, graphite, lithium, and manganese. Tracing the source of these minerals in what is called “full-cycle economics” reveals that lithium-ion may not be a good solution. A recent United Nations report warned that the raw materials used in these batteries are mined in countries that utilize child labor and produce high local carbon emissions. These minerals are not sustainable. In addition, toxic chemicals are needed to process lithium. Leaching, spills, and air emissions of these chemicals can harm entire ecosystems, community occupants, and food production. The extraction harms the surrounding soil.
In general, with the exception of sodium-ion, one must install more battery storage than needed to address power needs during recharge or have some type of handoff to alternate energy when they need to charge. But the sheer volume of batteries of any type is not a sustainable number. You could never replace the electrical grid with battery storage, it simply is not possible.
Recycling old batteries can be an issue. They don’t charge forever and not all of the core materials are recyclable, with the exception of sodium–ion, which is the most promising battery technology. With sodium-ion, the materials used in the core are not rare. In fact, they are commodities and would be classified as no-conflict materials. They don’t require massive amounts of earth to extract what is needed for a single battery. They don’t require conditioned buildings and are nonflammable. The batteries themselves can have a second life via secondary markets. Once they are fully discharged, they can be recycled into concrete additives that provide additional strength. Further, the rapid charge time decreases the need for additional “just in case” batteries — one can simply purchase and install what is needed.
Other Renewable Components
Beyond battery requirements, solar and wind have other components that are not recyclable and have a shelf life. Turbine blades on windmills are difficult to recycle. They are generally made from composite glass or carbon material. Unlike steel and copper, these materials are not as valuable when recycled. According to chooseenergy.com, with blades spanning up to 260 feet (which need to be cut up adding to energy costs) and weighing in at an average of 36 tons, old and broken blades pose a disposal problem in the U.S. Due to the fact that they are difficult to recycle, many turbine owners turn to less green methods, such as disposing the blades in landfills or worse, burning them. According to NPR, more than 720,000 tons of blade material will be disposed of over the next 20 years. The issue of blade disposal cannot be ignored. Work is underway to come up with better recycling methods.
Photovoltaic solar modules also last around 20 years, and warranties state that they will provide up to 80% of power over that life cycle. In general, they degrade about 1% each year of use. According to “Emissions from Photovoltaic Life Cycles,” to be published in Environmental Science & Technology, one square meter of solar cells carries a burden of 75 kgof CO2 in the best case and 314 kilograms of CO2 in the worst case. So, total CO2 debt for one household is 600 to 3,140 kg in sunny places and 1,200 to 6,280 kg in less sunny regions. The potential environmental impacts associated with solar power include the amount of land used and the resulting habitat losses, water use, and the use of hazardous materials in manufacturing. So, while solar is renewable, it certainly isn’t without carbon burdens.
Fossil fuels receive the worst press. While we all agree that coal and diesel are not the best sources of fuel, to say that we would simply switch over to renewables like flipping a switch is not realistic. However, if we look at natural gas and the sequestration and reuse of CO2, we have an environmentally significant next step. The Allam-Fetvedt Cycle burns natural gas with pure oxygen. The resulting CO2 is recycled through the combustor, turbine, heat exchanger, and compressor, creating lower-cost power with zero emissions. Yes, you read that correctly zero emissions — zero carbon and particulates with zero water required. From a power-usage perspective, it is possible to build a zero emissions data center today utilizing natural gas in a smaller footprint than a traditional natural gas power plant. Further, the captured CO2 can be put to useful purposes.
CO2 can be used to boost yield in greenhouse and strengthen concretes and cements. It is also used in the food and beverage industry as well as in medical procedures, among other.
Users that pay extra for greener energy simply can’t say where they are getting their power if they are buying it off the grid. Rather you have to assume that it’s there and your money for offsets is going to good use. There is a difference, after all, between green and sustainable.
Data Center Benefits
Data centers utilize electrical grid power from various origins (some green, some not at all), including switchgear for cutover to UPSs (battery and other) to provide standby power in the event of failure until generators come online to supply power until the grid comes back up. This chain is provided at least once for primary power, generally duplicated for secondary power, and, in some cases, duplicated once again to ensure that two power distribution lines exist and are live at all times including during maintenance. From one data center to our backup data center, the three power distribution paths provided twice (once at each site) further invites waste. Allocated primary power often is rarely fully utilized, leading to additional waste. Standby power is just that — rarely consumed and wasted.
Due to power failures and the drive for uptime, IT equipment (servers, switches, routers, storage, etc.) have developed to provide failover from one system to another in the event of failure. So, all of the IT equipment has two power supplies, two network connections, two storage connections, and so on. The software failover provides IT redundancy on top of power redundancy. One application is supported by three power distribution lines and dual IT paths. With a main data center and a hot failover data center, this doubles again, and with multiple edge locations, this can multiply without rhyme or reason. This all provides waste!
If we rethink from the application first and then evaluate the uptime needs of that application, we would find different levels of redundancy needs across a corporate suite of applications. To rethink this a bit further with a mind to eliminate waste, if we have one data center supplied by traditional grid power and one data center that had natural gas, carbon sequestered, carbon zero power, we technically have the same power failover without the waste. However, we have better redundancy as we have geographic diversity. The likelihood of the power grid and the natural gas supply both going down would mean that there was a significant event impacting two disparate facilities. Unlikely! But in this scenario, all of the wasted backup standby power at each location wouldn’t be needed as the power originates from two disparate sources. Single backup sources at each site would still eliminate the third power distribution leg at each site. IT equipment can failover as needed. The results are, simpler, smarter, and greener. We can, in fact, build data centers that are both off the main electrical grid and carbon zero.
Remember, just because you’re using wind/solar or buying credits for those energy sources doesn’t mean they don’t have a carbon footprint. And it doesn’t mean they don’t have an environmental impact on their surrounding ecology. If we’re really going to figure out how to reduce emissions and help restore balance to our environment, it’s going to take an “all of the above” approach with everyone working together to find solutions and doing the best they can with the available technologies.