How renewables can keep the lights on when the sun doesn't shine

Solar and Wind Power
CC BY-SA 2.0 Flickr

"Wind turbines, what a joke. What are we going to do when the wind isn't blowing?!!"

Alongside the "turbines kill birds" rallying cry, the intermittency of renewables is a frequent refrain for anti-renewables advocates. It's true that both the decentralized model of renewables and the intermittent nature of weather present a significant challenge for our current energy infrastructure. That infrastructure, after all, was built on a predictable, linear model based on extracting resources, converting them into power, and then pushing them down the line to an end consumer.

As our methods of generation get more sophisticated, however, and as our technological capabilities get more advanced, there are countless ways that the intermittency problem is getting tackled.

Here are just a few of them.

Better wind turbine design

Turbines have been getting bigger, and more efficient. As part of that process, the capacity factor has also been going up, meaning more power is produced at lower wind speeds - evening out the peaks and troughs that are associated with intermittency. This new generation of wind turbines from Siemens, for example, achieves a class-leading capacity factor of 54 percent. (It also integrates battery storage, but more on that later.)

Innovative new solar panels

Thin-film solar panels have long been touted as an answer to producing solar in more shady environments. From new panels based on the design of moth's eyes to dye-sensitized self healing solar cells, there's plenty of ideas out there for generating more from less. Industry insiders tell me it's all a long way off from commercial reality but still, it's nice to hear that folks are working on it.

Matching supply with demand

Despite being a deadly, UN-lead conspiracy to take over our lives, the smart grid has a lot to be said for it. By sending price signals to consumers, a smart grid would better match supply with demand - encouraging you to run your laundry when the sun is shining, or the wind is blowing, and charging you more if you ignore those signals.

Grid-scale energy storage

From the energy-storing wind turbine mentioned above through grid-scale compressed air storage to gigantic battery banks that are finally coming of age, there are several projects around the world looking at large-scale storage of power. Even when they have relatively small capacity, such systems can play an important role in making the economics of renewables viable—allowing power generators to maximize their profits by storing energy and selling it to the grid when it is most needed, and when it fetches the highest price.

Distributed energy storage

SolarCity and Tesla Home Energy StorageSolarCity/Screen capture

From Tesla's partnership with SolarCity to electric cars that can talk to the grid, distributed energy storage will also play a role in the energy system of the future. Why worry about a blackout when you've got power saved up at home?

Using less energy

LED light bulbs© Michael Graham Richard

Batteries and smart grids will only get us so far, conservation and efficiency still have a huge role to play. Fluctuating supply is, after all, less of a big deal if you have much less demand. So from LED light bulbs to smaller apartments, cutting consumption doesn't just decrease consumption itself—it actually changes the viability of producing cleaner power too. And that's got to be a win-win for all of us.

Making more power

Storage is one thing, but there's another way to ensure we get enough power too—and that's to produce too much. A recent study showed that, in some cases, it's better to overbuild renewables capacity than to factor in storage. In other words, there are instances where it's better to plan on wasting energy when you can't use it than to short change yourself on generation capacity. Exactly how we build enough clean energy capacity to oversupply the world remains a major challenge—although solar double cropping on farmland may get us some of the way there, not to mention the gigantic offshore wind farms that are now beginning to appear. (Offshore wind, by the way, suffers from much less intermittency than its onshore counterpart.)

It goes without saying that I am neither an energy grid expert nor a clairvoyant prophet, and many of the ideas above may never see the light of day. The future of our energy supply will look nothing like its past. The intermittency of renewables remains a significant challenge to a low carbon future, but it's a challenge that's being grasped whole heartedly by academic researchers and private industry alike. I look forward to watching what emerges.

How renewables can keep the lights on when the sun doesn't shine
Critics of green energy argue that intermittency is a fatal flaw. Advocates, however, are working on solutions.

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