Environmental Engineering Reference
In-Depth Information
Figure 2.2: Steel and Iron Required per Megawatt for Wind, Coal, and Natural
Gas
Sources: ALPINE Bau GmbH, July 2014; Peterson, Zhao, Petroski (2005); Wilburn 2011
Such resource requirements are a big cost problem, to be sure, and would be one even if the sun shone
all the time and the wind blew all the time. But it's an even bigger problem that the sun and wind don't
work that way. That's the real problem—the intermittency problem, or more colloquially, the unreliability
problem.
As we saw in the Gambian hospital, it is of life and death importance that energy be reliable. There are
some situations where it isn't, to be sure, and solar has a place there—such as solar hot water heaters or
swimming pool heating systems. But for just about everything we do, reliable, on-demand energy is vi-
tal—and without it, our electricity grid blacks out.
We know from experience that the sun doesn't shine all the time, let alone with the same intensity all
the time, and the wind doesn't blow all the time—and leaving aside the assurance that the sun will be “off”
at night, they can be extremely unpredictable.
To hear opponents of fossil fuels discuss the issue, though, the unreliability of solar and wind is no
obstacle at all, as evidenced by, above all, the success of Germany in powering itself via solar and wind.
In late 2012, Bill McKibben described “what's going on in Germany” as “un-[expletive]-believable” and
said “there were days this month [December] when they got half their energy from solar panels.” 17
And it appears that the news is just getting better. The Center for American Progress reported on May
13, 2014, that “Germany Sets New Record, Generating 74 Percent of Power Needs from Renewable En-
ergy.” 18 But taking a look at Germany's official energy statistics tells a very different story. Figure 2.3
shows how much of Germany's energy actually came from solar and wind throughout 2013, compared
with how much was typically needed during each month. 19 Notice how unreliable the quantity of solar and
wind electricity is. Wind is constantly varying, sometimes disappearing nearly completely, and solar pro-
duces very little in the winter months, when Germany most needs energy.
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