Greening the Grid 2011

The University of Wisconsin EnergyHub sponsored a conference on Friday on the future of energy and the potential for greening the grid.

The event featured a variety of speakers, from the state public utility commission to a professionally trained futurist. I learned a lot of really interesting stuff. Some highlights include that the future of wind and solar energy depends on the future of batteries, that building a smart, efficient grid brings privacy and security concerns, and that several local companies have devised some really interesting ways to increase their sustainability.

Many of us take the constant presence of electricity for granted. Whenever we want it, we flip a switch, and the power is there, waiting to charge a laptop or crisp some cold bread into toast. However, the tricky thing about the electricity is that we continuously have to be making as much as we are using.  Make too much, we can’t store it. Make too little, we’d have blackouts.  So forecasting precisely how much electricity is needed every day, and scaling production to that need is critical to a functioning power grid.

The problem is, for any given day, it’s hard to forecast exactly how much the sun will shine or the wind will blow. These renewable resources are called Intermittent Resources, because we can’t use them at a consistent rate, like a nuclear plant or adjust their production like a natural gas power facility. 

Wind farms typically produce more power at night, when the demand for electricity is lower.  This extra electricity can actually be an expensive problem for utility companies, because they have to compensate for the extra wind power with less coal power or natural gas power. These traditional power plants have minimum generation levels, or they have to be shut down.  If they have to be shut down, it takes time and energy to ramp them back up to production.  Meaning, that if you have to shut the coal power plant down at night because your windmills are spinning, it is much more expensive to turn the coal plant back on then it would have been to leave it running all night.   Alternatively, if you are relying on your wind farms, and the wind suddenly stops, it is also expensive (and slow) to ramp up that coal fired power plant to meet the difference between supply and demand, and people may be without power until the gap is closed.

Now, with wind and solar energy only providing about four percent of the national electricity, these problems created by the intermittent nature of these power sources is just an inconvenience that utility companies have to deal with.  To increase these renewable resources to 40 percent of the power supply, on the other hand, would make these inconveniences into huge supply problems.

The solution getting the most traction right now is electricity storage.  Giant batteries that could store the extra wind power produced at night and save it for a time when the wind stops. Currently,  storage is very expensive.  David Donovan, from Xcel Energy explained that storage costs have to come down close to production costs before large scale storage would be economically viable.  But, increased reliance on wind or solar won’t be viable until the storage is. Xcel energy is testing several storage projects, including a sodium sulfur battery the size of a 18-wheel truck trailer. With a million dollar price tag, it’s not cost efficient yet, even though it’s working well.

Garry Golden, the professional futurist, suggested that the solution to the intermittent resource problem might be to use wind or solar power  directly to create fuel, by producing hydrogen to use in hydrogen fuel cells.  Xcel energy is currently working with a prototype of this wind to hydrogen technology. The hydrogen can be stored much better than electricity, but can be used to produce power in a fuel cell in the future.  Golden also suggested that this sort of technology would move us toward a more distributed, less grid reliant energy future.

I left the conference with a better understanding of what renewable resources can do and the challenges they present. Ocean renewable energy was not mentioned, perhaps because this was a Wisconsin based conference, but tidal, wave, and ocean current energy all have the major advantage of being a renewable resource that is much more predictable and consistent than wind and solar. I’ll be writing more on that soon. Although it sounds appealing for environmental reasons, we can’t just suddenly replace all of our fossil fuel power production with wind farms with a wave of a magic wand.  Instead, the story sounds like it is shaping up to become an increasingly complex network of traditional and renewable energy production as we improve the technology, like large scale energy storage, that will allow us to move away from fossil fuels permanently.

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