Everyone knows that solar and wind power are variable energy sources; neither on its own produces electricity 24 hours a day, 7 days a week, 365 days a year. For that matter, no electricity source can do that indefinitely: nuclear reactors have to be shut down for weeks for refueling every 12-18 months and occasionally suffer unplanned shutdowns; coal plants break down and need repairs, so do gas-powered turbines.
Thus, backup power is needed whatever the main source of power may be. In solar and wind’s case, their variability is more pronounced. But their variability is predictable: for example, grid operators know that solar isn’t going to produce at night, when the sun is down. Of course, power demand is down most of the night too–not as big a problem as it might appear.
These days knowledgeable grid operators can and do predict pretty well how much power a given solar installation is going to produce tomorrow and adjust the grid’s needs accordingly. Same with wind. It’s simple weather forecasting factored into a complex grid. So even though solar and wind are variable, they are normally producing power when it is needed most (times of highest electricity demand in most climates tend to be hot summer afternoons, when solar is at its most effective).
Still, solar and wind are rarely, even in tandem, providing full capacity 24/7 and thus do require backup power. At the moment, that power is generally just supplied by the overall grid. But as solar and wind continue their rapid growth and represent a larger percentage of generation sources while fossil fuel and nuclear-powered plants close, they’ll need a different type of backup power.
That’s called energy storage and it barely existed even ten years ago. Today however, energy storage appears to be where solar power was a decade ago: on the verge of rapid cost decreases that will make it feasible for both utility-scale power plants and smaller-scale–even household level–distributed energy systems.
Several knowledgeable observers have pointed me to Southern California Edison’s 2.2 Gigawatt grid modernization plan, announced in November, as a harbinger for the utilities of the future. The plan combines hundreds of megawatts of distributed solar projects along with 250 MW of both large and small-scale storage technologies. Developed partly as a replacement for the power lost by the shutdown of its San Onofre reactors, if this plan works as it should, it will be a giant leap toward a 100% renewable energy future in California.
Meanwhile, over in Texas, a company called Oncor, the largest power transmission and distribution company in Texas, wants to spend $5.2 Billion to buy “5 gigawatts of batteries to store electricity at night when power production cost is low and ship it during the day when electric prices are high.” The batteries are specifically for wind power, which is abundant in Texas.
Opposing Oncor is the north Texas utility Luminant, which sees a threat to its market. Oncor is not allowed, under Texas law, to actually produce power–it only distributes it. Luminant fears that if the giant storage project is approved, Luminant might not get to build new power plants, because they won’t be needed. Luminant claims that Oncor’s proposal would raise utility rates; of course, new power plants (and Luminant hasn’t yet given up on the idea of building new reactors at its existing Comanche Peak site) also tend to raise utility rates–a lot.
Ultimately, an even bigger threat to the traditional utilities may be posed by rooftop solar supplemented with battery storage. With adequate solar and storage installed, homeowners and businesses wouldn’t need the utilities or the grid anymore. While some studies have shown that homeowners with such systems would tend to stay on the grid anyway, just as an extra backup source, the utilities wouldn’t be selling much, if any power to them. Indeed, they might be buying more electricity from them than they would be selling.
To date, such battery systems are still pretty expensive for most homeowners. But that is changing rapidly, in the same way that solar prices plummeted over the past decade to where it is now just as cheap in most states to install rooftop solar as it is to buy power from the local utility. Already, in Germany, prices are dropping–by about 25% in just the past six months.
In Japan, Panasonic is developing a 1,000 household “smart town,” centered on solar power and storage–the first residents moved in this past Spring.
Here in the U.S., as we’ve reported before, Elon Musk’s Tesla has broken ground on a “gigafactory” in Nevada that aims to both drastically lower the cost of battery storage and produce gobs of such batteries–enough to power Tesla’s growing car business as well as SolarCity’s (owned by Musk’s cousin) even faster-growing rooftop solar business.
In short, the energy revolution brought about by the remarkable advances in solar and wind technology over the past decade, coupled with their equally remarkable cost reductions, is nowhere near at an end. Indeed, we’re only at the beginning–and the days of the behemoth “baseload” power plants of the 20th century are rapidly fading, regardless of what the nuclear industry and its proponents would like you to believe.
December 15, 2014
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