“The main problem facing renewable energy is that the biggest sources, wind and solar, are variable. Whereas fossil fuel power plants that run on coal and gas are “dispatchable” — they can be turned on and off on demand — wind and solar come and go with, well, the wind and sun.
Building an electricity system around wind and solar thus means filling in the gaps, finding sources, technologies, and practices that can jump in when wind and solar fall short (say, at night). And the electricity system needs to be extremely secure and robust, because decarbonizing means electrifying everything, moving transportation and heat over to electricity, which will substantially raise total electricity demand.
The big disputes in the clean energy world thus tend to be about how far wind, solar, and batteries can get on their own — 50 percent of total power demand? 80 percent? 100?) and what sources should be used to supplement them. (See this much-cited 2018 paper in the journal Joule on the need for “firm, low-carbon resources.”)
The answer currently favored by renewable energy advocates is more energy storage, but at least for now, storage remains far too expensive and limited to do the full job. The other top possibilities for “firming” electricity supply — nuclear power or fossil power with carbon capture and sequestration — have their own issues and passionate constituencies for and against.
Geothermal power, if it can be made to reliably and economically work in hotter, drier, and deeper rock, is a perfect complement to wind and solar. It is renewable and inexhaustible. It can run as baseload power around the clock, including at night, or “load follow” to complement renewables’ fluctuations. It is available almost everywhere in the world, a reliable source of domestic energy and jobs that, because it is largely underground, is resilient to most weather (and human) disasters. It can operate without pollution or greenhouse gases. The same source that makes the electricity can also be used to fuel district heating systems that decarbonize the building sector.
It checks all the boxes.”
“Tapping into it, though, turns out to be pretty tricky.”
“Though hydraulic fracturing as a technique has been around since the 19th century and the first commercial fracking for gas took place in the 1940s, the most recent fracking boom started in earnest around 2005. That’s when the rising prices of oil and gas forced energy companies to look for other sources, when related techniques like horizontal drilling and low-cost slickwater fracking matured, and new estimates revealed the gargantuan amounts of gas stored in formations like Marcellus Shale.
Fracking has now become the dominant technique for extracting oil and gas in the US.”
“During much of the fracking boom, the US economy grew and emissions declined. One study found that between 2005 and 2012, fracking created 725,000 jobs in the industry, not counting related supporting jobs. “This has been one of the most dynamic parts of the U.S. economy — you’re talking about millions of jobs,” Daniel Yergin, vice chairman of IHS Markit and founder of IHS Cambridge Energy Research Associates, told CNBC.
That’s largely due to natural gas from fracking displacing coal in electricity production. Natural gas emits about half of the greenhouse gas emissions of coal per unit of energy. It doesn’t have the massive land footprint that open pit mines or mountaintop removal coal mines do. While it has its own pollution problems, burning natural gas doesn’t produce pollutants like ash and mercury, which can pose health and environmental hazards for years.”
“Natural gas’s flexibility has also eased the integration of variable renewable energy sources like wind and solar power. When the breezes slow down and clouds form above, natural gas steps in. This has reduced the need for other ways to compensate for intermittency, like energy storage.”
“fracking has helped insulate the US from global economic shocks, particularly in oil markets. US shale oil has provided more than half the growth in global oil supplies, so rising tensions and disruptions in countries like Iran, Libya, and Venezuela have barely moved the needle at the gas pump.”
“natural gas obtained by fracking has reduced emissions, aided the economy, and helped clean energy rise, while costing less than dirtier fuels.”
“while low natural gas prices have helped knock dirty coal off the market, low oil prices driven in part by fracking have encouraged more travel. In fact, transportation is now the largest source of greenhouse gases in the US. And after years of decline, US emissions in 2018 rose by 3.4 percent.
Low oil prices have undermined the business case for cleaner transportation alternatives, like electric cars and fuel cell-powered buses. Instead, the United States has experienced a growing appetite for larger, thirstier cars and more air travel.
Meanwhile, low natural gas prices have had some collateral damage for nuclear power, the largest source of clean electricity in the US. Some of the nuclear power plants that have announced early retirements are likely to see their capacity replaced by natural gas. So while replacing coal with natural gas often leads to a reduction in emissions, replacing nuclear energy leads to an increase.
Natural gas itself can also become a climate problem. Methane, the dominant component of natural gas, produces less carbon dioxide than coal when burned. But if methane leaks, which it often does in some quantity during normal gas extraction operations, it becomes a potent greenhouse gas. Over 100 years, a quantity of methane traps more than 25 times the amount of heat compared to a similar amount of carbon dioxide.”
“then there’s the technique of fracking itself. It requires a massive volume of water. Wells can release toxic chemicals like benzene into the air. Fracking sites can experience explosions and fires. They can contaminate drinking water. More than 17 million people in the US live within a mile of an active fracking well, and research shows that fracking can lead to low birth weight in infants born in that radius.
Many of these environmental risks, on balance, are less than those associated with mining and burning coal. However, the sudden surge in fracking means many people are being confronted with its impacts for the first time, making it a more vivid political concern. That’s in contrast to coal hazards, which are mostly familiar to the public consciousness.”
“when it comes to limiting climate change, a key factor is time. Methane leaked from gas wells can stay in the atmosphere for a decade. Carbon dioxide from burning it can linger for a century. So it is imperative to ramp down greenhouse gas emissions as quickly as possible. Yet every new natural gas power plant represents a decades-long commitment to continue using the fuel. That means gas plants will have to install carbon capture systems, which would add to their operating costs and worsen the business case further, or some poor investor is going to be left holding the bag.”
“To a first approximation, the question of whether renewables will be able to get to 100 percent reduces to the question of whether storage will get cheap enough. With cheap-enough storage, we can add a ton of it to the grid and absorb just about any fluctuations.
But how cheap is cheap enough?
That question is the subject of a fascinating recent bit of research out of an MIT lab run by researcher Jessika Trancik (I’ve written about Trancik’s work before), just released in the journal Joule.
To spoil the ending: The answer is $20 per kilowatt hour in energy capacity costs. That’s how cheap storage would have to get for renewables to get to 100 percent. That’s around a 90 percent drop from today’s costs. While that is entirely within the realm of the possible, there is wide disagreement over when it might happen; few expect it by 2030.”
“It’s important to test renewable energy over longer time spans. In addition to daily and weekly fluctuations in solar and wind, there can be yearly or even multi-year fluctuations. And indeed, by looking back over 20 years, the team found several rare events in which wind and solar were both unusually low for an unusually long time. These rare events represent a spike in the amount of storage needed. Planning for them substantially increases the cost of a pure-renewables system.”
“these researchers set an extremely high bar: a system with all-renewable energy, with flexibility handled entirely by storage, adequate to meet demand at every hour of every day for 20 years.
Soften any of these restraints even a little and the cost target that storage must meet rises to something far more tractable.
First and most notably, loosen the amount of time that the system must meet demand and things get much easier for storage. And a 100 percent EAF is a little crazy anyway; the existing power system is not up and available 100 percent of the time. There are brownouts and blackouts, after all. No power system is 100 percent reliable.
Trancik’s team found that if the EAF target is lowered from 100 to 95 percent, the cost target that storage must hit rises to $150/kWh. (More specifically, lowering the EAF reduced the total cost of energy storage by 25 percent for the first tier of storage technologies and 48 percent for the second tier.) That’s a much more tractable number, within reach of existing technologies.
Why does lowering the EAF so little ease the pressure on storage so much? The explanation is in those rare meteorological events of extended low wind and sun. They don’t happen often over a 20-year span, but building enough storage to deal with them when they do happen makes the last few percent of EAF exponentially more expensive. To lower the EAF to 95 percent is to say, “something else can handle those rare events.””
“the team is modeling a system in which storage is doing almost all the flexibility work. In fact, there are other sources of grid flexibility. My favorite candidate for flexibility dark horse is “load flexibility,” demand-side programs that can shift energy consumption around in time. Another source of flexibility is enhanced long-distance transmission, to carry renewable energy from regions that produce it to regions that need it. Another is dispatchable renewables like run-of-the-river hydro and advanced geothermal.
All of those sources of flexibility will grow and help to smooth out renewables. Storage won’t have to do all the work on its own. That, too, should ease the price pressure.”
“a renewables+storage system also gets easier if renewables get cheaper. The numbers that Trancik’s team use for renewables are quite conservative. (For instance, $1/Watt solar costs are already being beat routinely in the US.) If renewable energy continues to defy expectations and plunge in cost, it would become cheaper and easier to oversize renewables and curtail the excess energy. That in turn would ease pressure on storage.”
“the headline $20/kWh cost target for energy storage is almost certainly more stringent than what will be required in the real world. Even the $150/kWh target required for an EAF of 95 percent is likely too stringent. In the real world, storage will be assisted by other forms of grid flexibility like long-distance transmission, load flexibility, and microgrids, along with regulatory and legislative reforms. And renewables will probably continue to get cheaper faster than anyone predicts.
So let’s call the target $150-$200, or thereabouts. Can storage hit that?”
“There are two key characteristics of a storage technology: power capacity and energy capacity. Roughly speaking, power capacity refers to how fast you can get energy out of it, measured in kW; energy capacity refers to how much energy you can store in it, measured in kWh. Each is priced separately, power capacity costs and energy capacity costs. The latter is the number we’ve been using for targets”
“It expects, by 2030, “a drop in the total installed cost for Li-ion batteries for stationary applications to between USD 145 per kilowatt-hour (kWh) and USD 480/kWh, depending on battery chemistry.” Hey, $145 is well within our target range!
Nonetheless, lithium-ion batteries are limited. Researchers generally treat the raw materials costs of a storage technology as the lower possible bound of its total costs. Manufacturing and transportation costs can be lowered with scale, but materials costs are stubborn, and the materials involved in Li-ion batteries alone are costly enough that they will likely never hit $20/kWh. In the $150 range, though — that’s doable.”
“How about flow batteries? “The two main flow battery technologies — vanadium redox flow and zinc bromine flow — had total installation costs in 2016 of between USD 315 and USD 1,680/kWh,” IRENA reports. “By 2030, the cost is expected to come down to between USD 108 and USD 576/kWh.” Yes, $108 is well within our target range. (Note that there are flow battery companies already claiming to beat that.)
High-temperature sodium sulphur (NaS) and sodium nickel chloride batteries have been around for a while, but they are also expected to get much cheaper. “Cost reductions of up to 75% could be achieved by 2030, with NaS battery installation cost decreasing to between USD 120 and USD 330/kWh,” says IRENA. “In parallel, the energy installation cost of the sodium nickel chloride high-temperature battery could fall from the current USD 315 to USD 490/kWh to between USD 130 and USD 200/kWh by 2030.” Again, at the lower end, well within our target range.
CAES costs are extremely site-specific, as they depend on a reservoir in which to pump the air. “The typical installation cost is estimated to be approximately USD 50/kWh,” says IRENA, “possibly dropping to USD 40/kWh if an existing reservoir is available.”
Then there are thermal-storage options, like the increasingly popular option of storing electricity as heat in molten salt, with claims of energy capacity costs as low as $50/kWh.”
“Storage is rapidly evolving, diversifying, and falling in cost, to the point that wind and solar power plants coupled with storage are beginning to compete directly with fossil fuel power plants on cost. That’s only going to accelerate as both renewables and storage get cheaper. Providing all of US power, all day every day, will require oversizing renewables and installing an enormous amount of storage, but if they get cheap enough, that’s what we’ll do.
To put that more plainly: A US energy grid run entirely on renewable energy (at least 95 percent of the time), leaning primarily on energy storage to provide grid flexibility, may be more realistic, and closer to hand, than conventional wisdom has it.”
“The Ohio case, while extreme, is not an aberration. Corrupt electric utilities using ratepayer funds to roll back climate policy is not limited to Ohio. As I described in Short Circuiting Policy, it is an unfortunately common pattern.
Last week, the Illinois utility ComEd — whose parent company is Exelon — admitted to engaging in bribery and agreed to pay a $200 million fine. It’s very likely that another speaker, Michael Madigan, is involved in that case — the Illinois governor has already called on him to resign.
In Arizona, which I examine in my book, the FBI similarly launched an investigation into an elected official over its ties to a private electric utility, Arizona Public Service. As we now know, Arizona Corporation Commission Chair Gary Pierce met privately with then-Arizona Public Service CEO Don Brandt numerous times. The utility also funneled over $700,000 through a dark money group to Pierce’s son’s failed bid for secretary of state.
Arizona Public Service also secretly spent tens of millions on campaigns to elect its own regulators in order to secure favorable decisions, including clean energy rollbacks and generous rate hikes. In 2018 alone, it spent upward of $40 million to successfully block a clean energy ballot initiative. The new CEO, Jeff Guldner, played a key role in directing the utility’s dark political spending.
And this isn’t a new strategy. Throughout the 1990s, electric utilities including FirstEnergy and Arizona Public Service were key funders of climate denial.”
“The dogged folks at the Energy and Policy Institute — a utility watchdog that has turned up real-time facts in most of these cases — paint a clear picture for those paying attention: Most electric utilities are resisting the clean energy transition and using corruption to do it.”
“Energy analysts, however, caution that Sanders’s 2030 plan would require a federal infrastructure investment not seen since the construction of the interstate highway system. To get close to Sanders’ 100 percent clean energy goal by 2030, researchers estimate the U.S. would need to add about 800 GW of wind and solar resources — about 25 times the amount the federal government expects to be built this year — along with ample amounts of battery storage and transmission. The Sanders camp forecasts that would cost about $2 trillion.
“Our best year for solar and wind — we’d have to multiply that by three and then sustain it for the next decade,” said Sonia Aggarwal, vice president at the analysis firm Energy Innovation, which advises world governments on their climate targets.
While turning the power grid over to 100 percent renewables presents significant technical difficulties, the clean energy deployment is “not out of the question,” Aggarwal said. However, Sanders’ plan to shut down nuclear power plants will make it “much more difficult.” The nation’s 60 nuclear plants generated more than half of U.S. carbon-free energy last year, but the Sanders campaign says it will phase them out by denying extensions of their operating licenses when they expire.
Many of those nuclear plants have licenses that expire after 2030, but Sanders expects the cheaper solar and wind power to drive most them into retirement. The stability those reactors provide to the power grid would be hard to replace with the variable output of the renewables, said Leah Stokes, assistant professor of political science at the University of California Santa Barbara.”
“Federal regulators are now actively working to counteract the effects of state-level clean energy policy, despite opposition from virtually everyone except the fossil fuel generators that directly stand to benefit. And by doing so, they will crank up costs on 65 million consumers (as a start).”