Data Centers Powered by Renewable Energy

Some well-informed data center operators are worried and even terrified about cap-and-trade regulations in the United States and the Carbon Reduction Commitment in the United Kingdom. I covered this issue in several past posts:

One way to avoid a carbon surcharge (whether directly charged or indirectly passed on from a utility company) is to use power generated by renewable energies, such as wind and solar. I blogged on both solar and wind power generation as they relate to data centers in my previous posts.

And Environmental Leader has published an article describing data centers powered by renewable energies.

From this article, I’ll first list data centers that are currently, or planned to be, powered by renewable energies like wind and solar: ::continue::


The article does not mention that both Microsoft and Google plan to build their data centers in Iowa (in West Desmoines and Council Bluffs, respectively). One reason they selected Iowa is to exploit the wind there.

Good-size data centers need somewhere between 1 MW and 5MW of power. Some may need as much as 50 MW, and some sites already have the necessary capacity for a data center of that size.

Looking at this table, I noticed a few things:

1. Solar power generation seems to be much more advanced than wind power generation, judging by the number of sites mentioned.

2. Solar appears to be concentrated in California.

3. Some sites have enough generation capacity.

4. Wind power generation is concentrated in the Midwest, but so far only two data centers are being located there to take advantage of wind power.

I talked to AltaTerra’s expert in renewable energy, Jon Guice, and asked several questions about these and other issues.

Question 1: Is solar technology more advanced than wind power technology? Which is more cost-effective in terms of both construction and power generation? More precisely, what are the different costs of power between the two?

Answer: The brief answer is, no, solar is not more advanced than wind power as a technology or sector, although it may be more frequently applied to data centers in the U.S. right now. Reasons for this could include the availability of suitable locations near the data centers and the fact that solar produces power during the afternoon, when retail power is more expensive and more people are online. However, we also note the approximate total production score in this table: solar, 4MW; wind, 150 MW. While over a period of twenty-five years, the global average total cost of operating wind power plants is lower—something like 10 cents per kilowatt hour or less rather than several cents more—either or both can make economic sense in various settings.

Question 2: Is solar deployment mostly in California? If so, what is the reason for that?

Answer: That’s right. In the U.S., the majority of solar electric power is generated in California. As we discuss in a new report, today Germany has the world’s largest photovoltaic (PV) market, at approximately 52 percent of the global total. The United States represents about 7 percent. California accounts for 4 percent of the global market. This is not only because California is a sunny state. California took an early lead with statewide and utility-led programs that now contribute to making the state a hotbed of innovation in renewable energy—with PV still in the lead.

Question 3: Is solar or wind more suitable for generating a large amount of power, like 5 MW and more? What about 50 MW?

Answer: The answer depends a great deal on the setting and conditions, and there are industry advocates on both sides of this question. However, in historical experience, with large power plants, wind power is a serious contender for inexpensive, reliable power.

Question 4: In my previous blog, I pointed out that wind power generation is concentrated in the Midwest. What about other places?

Answer: There are a lot of windy places in the world. Every few years for the past decade new research has shown that there is more wind power potential than previously thought. In the U.S., California was for many years the state with the most wind power, but there is significant wind power now in fifteen states. According to the American Wind Energy Association, as of 2008, the top five states were (in order) Texas, Iowa, California, Minnesota, and Washington. Texas is the leader right now, with more than 7,000 MW installed as of the close of 2008. The other states range from 1,500 to 2,700 MW. While there is a “wind alley” that extends from Texas into the upper Midwest, there are also many other windy regions throughout the country.

Question 5: What is the cost of power generated by solar or wind? How does it compare with the current cost?

Answer: Without going into economic and financial details—which we frequently do for both vendor and buy-side clients—here are some guidelines that are actually more meaningful in most cases. First, we normally use cost per kilowatt hour, as this is the common denominator in business. Second, as we noted above, in large-scale applications, wind power is inexpensive—under 10 cents per kilowatt hour—while solar power is more expensive than that.

Question 6: Is the carbon footprint of solar and wind power plants zero? If not, what part of the power generation emits greenhouse gases?

Answer: There is no energy source with zero carbon emissions, but renewable energy sources have extremely low emissions. Nonetheless, the solar and wind industries are reducing their footprint. AltaTerra Research has just started a project working with the PV industry on the topic.

Question 7: In order to support both solar and wind generation, two technologies are a must. One is for storing the generated energy and the other is for incorporating it into the existing power grid. Is the storage technology advanced enough to be usable? A data center needs to have access to the fiber network in addition to abundant power. Because of this, a data center may not be built close to either solar or wind power plants. If so, generated power needs to be incorporated into the exisitng power grid. What are the current problems in incorporating the power generated by solar or wind power plants into the existing power grid?

Answer: There are various differences between solar and wind power and other, more widespread power generation technologies, some of which can create problems for utilities. One of the key problems is that the utility can’t tell the sun when to shine or the wind when to blow. Rather, these are intermittent resources that can be smoothed out by using stored energy. Connection to the grid can be through a special, dedicated link (often with new transmission lines) or by tapping into the existing network—including at the branch level. While some utilities are not experienced in dealing with large amounts of solar or wind power, the threshold of feasible power from solar and other renewable resources is now held at around 20 MW for a branch-level connection.

Based on Jon’s answers, I conclude:

1. Although it takes time and money to construct a new solar or wind power plant, a data center that is wholly supported by renewable energy sources is within reach. In this case, it is very clear that the power generated by renewable energy and the data centers that are supported by it should be exempt from carbon regulations.

2. Drawing a new set of fiber cables that lead to Internet access points is also expensive. If a renewable energy power plant happens to be near fiber lines, it would be great. But if not, the generated power needs to be stored or transmitted by merging into the existing power grid. More research is required on energy storage technologies, although a significant amount of investment is being made. Simply laying new transmission lines to connect to the existing power grid is expensive in itself. Additional consideration may be necessary to make sure the existing power grid can keep up with the extra capacity fueled by the new power plant. Without extra capacity, the new source of power cannot be connected to the existing grid.

3. The whole story makes me feel very good, as this will encourage construction and produce something that is friendly to the environment and the earth, generating more jobs and making our economy stronger at the same time.


Zen KishimotoBy Zen Kishimoto, PhD, Principal Analyst, Green IT, AltaTerra Research

You can also find this blog post and more on under Zen and the Art of Data Center Greening.


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AltaTerra Research is a research consultancy specializing in sustainable business and the commercial marketplace for clean technology solutions. Through research reports, executive events and advisory services, AltaTerra helps forward-looking organizations improve resource-efficiency in their operations and capitalize on new 'green' market opportunities. From our headquarters in Silicon Valley, we have been serving a global base of corporate, institutional, and government clients since 2007.

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