The drive for green data centers often focuses on improving energy efficiency through means such as free cooling, virtualization, consolidation and so on. Another facet is use of alternative energy sources, like solar and wind power. For instance, Apple’s data center in Maiden, North Carolina, uses a large solar array, as well as fuel cells, for much of its power supply. The company is also planning another large solar array for its Reno, Nevada, facility. Many organizations that want a greener image for their data centers are likewise considering alternative power in one form or another, and governments are pushing for a move away from coal. But it’s easy to look simply at the power-generation side of these sources while ignoring other factors, such as manufacturing and waste. Coal produces carbon and other emissions when generating electricity; solar and wind infrastructure doesn’t. But what is the price of manufacturing this infrastructure? When these outside costs are considered, the situation is less clear.
Fiscal Costs Aside
The economic effects of an artificial (i.e., not market-driven) move toward alternative energy creates a variety of problems, not the least of which are higher costs for consumers—which have particularly grievous effects on those of lesser means—and an unstable market that produces failures like that of the now legendary Solyndra. These effects can be the result of government subsidies, direct taxes or cap-and-trade schemes that inflate prices for reasons beyond those of supply and demand. These considerations are all legitimate, but they are not the primary focus of this discussion, which instead looks mainly at the environmental hazards of pursuing alternative energy—particularly, the manufacturing process for the infrastructure rather than the electricity-generation process per se.
Wind: Toxic Waste?
If you think of wind power, you probably think of large white turbines serenely spinning in green pastures among herds of grazing cows. That may be the end product (you might have to ignore the hazards to birds, though), but the manufacture of wind turbines relies on the use of so-called rare earth minerals. But mining and processing of these “rare earths” yields a variety of hazardous and radioactive byproducts that, if not properly handled, can cause tremendous harm to both people and the environment.
Currently, most rare earth production is done in China, where environmental regulations are much laxer. As a result, the cost of the products is lower in currency, but much higher in environmental damage. Current U.S. policy, which is focusing on penalizing coal power and subsidizing other forms of electricity generation, essentially outsources the less savory task of rare earth production. A lack of commensurate focus on rare earth mining and processing at home thus encourages practices that may not be up to the same environmental standards that proponents of wind power are pushing on coal and nuclear. To be sure, rare earth mining under more-stringent environmental standards means higher costs of production, but to reduce costs at the expense of poorly regulated mining practices is to compromise on the principle.
Thus, when a company like Google invests in wind energy for the sake of its environmental and other benefits but doesn’t weigh the associated costs, it is being at least slightly disingenuous.
Solar Power: Energy to Produce Energy
A favorite of companies like Apple is solar energy. And why not? The sun pours energy on the Earth, providing a tremendous opportunity. But using that energy requires converting light into electricity—enter the solar panel. Manufacturing solar panels, however, requires nontrivial amounts of energy; in the case of silicon-based solar panels, which are the most common type, the silicon material requires melting silica rock in roughly 3,000°F ovens. That energy, however, typically comes from coal plants, meaning that although solar panels may produce no emissions when in operation, they indirectly produce a fair amount during manufacturing.
Another consideration is waste. Not only do solar panels have limited lifetimes (some 20 to 30 years, depending on the estimate), hence the need to deal with waste panels, the manufacturing process produces a variety of waste chemicals that must be properly disposed of or recycled. That takes energy and labor. Like wind, simply looking at the electricity-generation process—which is remarkably clean—is insufficient to understanding the true costs of alternative energy.
Hydrogen: Ozone Holes?
Another energy source that has garnered some interest from data center operators is hydrogen. Hydrogen can be used in fuel cells to produce electricity, with the only byproduct being water vapor. It can also serve as fuel in combustion engines, greatly reducing emissions compared with oil-based fuels. Apple, for instance, has deployed fuel cells as part of its own energy mix for its Maiden data center.
As with other alternative sources, however, hydrogen has its costs. A paper by Frank A. Coutelieris notes that two important methods of producing hydrogen (electrolysis of water and steam reforming) require energy input. Currently, that means most coal-based energy, although in a more alternative-energy-based system, the power source could be the sun or wind. In addition, however, transportation of the fuel from its production point to the point of usage requires more energy—meaning oil, presently.
Furthermore, owing to the difficulty of containing hydrogen, leakage is inevitable. Large-scale use of hydrogen, combined with losses of about 10% to 20% into the atmosphere, could damage the ozone layer, according to Physics World.
A Balanced Look at Alternative Energy Sources
The ability of “green” energy sources to produce electrical power without many of the harmful side effects of, say, coal and nuclear are clear. But ignoring the potentially damaging effects of the manufacturing processes is unhelpful. For instance, what if the damage caused by rare earth mining to enable wind turbines outweighs the benefits of wind power over coal? This is not to say that wind yields no net benefit, but considering the costs is critical to an honest assessment. The same applies to solar- and hydrogen-based power.
Considering the increasing focus of governments in the U.S. and elsewhere on alternative energy—often for reasons of environmental protection—a meticulous study of the hazards of infrastructure and fuel manufacturing is necessary. It may turn out that the relative benefits of, say, solar power outweigh the relative costs; perhaps waste products can be handled safely and efficiently enough to largely eliminate any environmental effects. Either way, however, these costs should be called out—particularly by a federal government that demands more alternative energy production but fails to provide similar encouragement for rare earth mining in jurisdictions that enforce adequate environmental protections.
The key in considering alternative power is balance: weighing the costs as well as the benefits, and seeking the right mix of sources to simultaneously minimize environmental effects and to maximize benefits to industry and consumers. Data center operators are in the business of IT, but many also consider the impact of their operations. For such companies, pursuing greener energy is commendable—but this pursuit should involve a careful assessment of the costs in addition to the benefits.
Image courtesy of existangst