Why batteries cannot address the intermittency issues of "renewables"
US electric generation from all sources in pre-COVID 2019: 4178 TWh (average 477.0 GW).Total EV battery capacity sold in 2021: 286.2 GWh.
This world-wide total could store enough energy to run the USA's average electric load for a whole 36 minutes.
(h/t: Green Car Congress)
Labels: batteries, renewable energy, storage
¶ 2/10/2022 04:32:00 PM 10 comments
More dangerous than Three Mile Island
Three Mile Island. The name still elicits fear, forty years later. Yet the whole accident had zero casualties; there were no deaths and no injuries.The list of energy-related accidents with greater tolls is long. Natural gas pipeline explosions have killed quite a few in just the USA alone. Oil wiped out the center of Lac Megantic in 2013, killing 47. And collisions between road vehicles and coal trains regularly kill and injure, mostly in ones and twos.
To this list of energy-related dangers we now must add... utility-scale batteries:
PHOENIX (AP) — Arizona's largest electric company installed massive batteries near neighborhoods with a large number of solar panels, hoping to capture some of the energy from the afternoon sun to use after dark.Despite the very small number of units in service, this is not the first battery fire. It won't be the last, either; current plans involve many more and much bigger installations. Running up a list of casualties while being such a minor component of the electric system ought to have people asking questions, like...
Arizona Public Service has been an early adopter of battery storage technology seen as critical for the wider deployment of renewable energy and for a more resilient power grid.
But an April fire and explosion at a massive battery west of Phoenix that sent eight firefighters and a police officer to the hospital highlighted the challenges and risks that can arise as utilities prepare for the exponential growth of the technology.
"Are these things safe to have in my neighborhood?"
"Are these things safe to have anywhere?"
Anyone who dares to ask those questions, though, is bound to come under vicious attack from the proponents of "renewables". Meanwhile, those same proponents spread fear of nuclear power, despite nukes being objectively much safer than even smallish utility-scale batteries.
Evil, or just crazy? It's got to be one or the other.
Labels: batteries, public health
¶ 6/25/2019 09:11:00 AM 2 comments
The EOS grid-storage system and nuclear power: a marriage made in heaven
EOS Energy Storage is peddling a megawatt-scale, fully containerized energy storage solution based on zinc-air (or zinc-oxygen?) cells. Self-contained in a standard 40-foot footprint, the cutaway shows blocks for batteries, inverters, and cylindrical objects which seem likely to be some sort of gas storage or perhaps filtering/processing system. The stated performance figures:- $1000/kW
- $160/kWh
- 75% round-trip efficiency
- Cycle life 10,000 cycles
- 30-year design calendar life
If they actually deliver at those specs, it's worth thinking about what it could do. For instance, at $1000/kW output and 75% round-trip efficiency, $300 million invested plus 2400 MWH input over 6 hours (400 MW) yields 1800 MWH output (300 MW) over 6 hours.
Let's try this as a hypothetical example with something else that's already coming: the AP1000, with 8 currently being constructed worldwide. This will supply base-load power which can be cycled to follow load, but is most economical if it's run flat-out. The AP-1000 is rated at 1154 MW(e), and the estimated pricetag per plant of about $8 billion at Vogtle isn't out of line for first-of-a-kind efforts.... batteries not included.
Let's add them. $300 million for 300 MW of EOS units bumps the pricetag to $8.3 billion. Charging at full power drops the net output from 1154 MW(e) to 754 MW(e). Maximum discharge increases the net output to 1454 MW(e), nearly twice the minimum. (This is considerably greater than the 1.67:1 day/night swing detailed for the eastern provinces of Australia.)
At full cycling, the daily output is (1154*24-600)=27096 MWh, or 1129 MW(e) average. Other attributes:
- Peaking: self-supplied (either centralized or distributed)
- Reactive power: presumably available from the EOS inverter systems, distributed with the storage units.
- Air emissions: zero.
- Spinning reserve: as much as 700 MW (the difference between 400 MW maximum charging rate and 300 MW maximum discharging rate).
Amortizing $8.3 billion over 20 years at 7% interest costs $772 million/year; divided over 1129 average MW at 0.9 capacity factor, I get 8.7¢/kWh. Selling off-peak power at 5¢, mid-demand at 9¢ and peaking power at 15¢ I calculate $913 million annual revenue vs. $772 million annual amortization (salaries and fuel not included). Even at the extreme first-of-a-kind price of $8 billion for the nuclear unit, this is clearly affordable. After 20 years the bonds are paid off and the system becomes a cash cow for likely 4 more decades or longer.
The value added by the battery is the difference in purchase (or opportunity) cost of the off-peak power and the sales price of the peaking power. At the same 0.9 capacity factor I see $49.3 million annual gross revenue from the battery, paying off in just over 8 years. Plainly the battery is pulling its fiscal weight! But it will also cut the supply of off-peak power (shifted to charging), so off-peak prices may increase. This would further improve the economics of the system as a whole.
The impact on unreliables
Would the EOS battery make the dream of an all-renewable grid possible? That's very doubtful, given the need to tide the system over lulls adding up to days of average output. 48 hours of storage would itself cost $8000/kW, or around 16¢/kWh even if it was cycled continuously (50% capacity factor). That's over and above the cost of the power to charge it, which is hardly cheap at feed-in tariff rates. What would people do, looking at that pricetag to go "green"? They'd go the way of Germany and Poland, and burn coal. If stored energy comes at caviar prices, we should not be surprised if people decide to eat energy "junk food" instead.
The impact of a carbon tax
Suppose for a moment that the current system of production and investment tax credits is replaced by a simple, non-discriminatory figure of merit: a straight-up carbon tax. Let's set this carbon tax at $40/ton of CO2, which matches the 2.2¢/kWh PTC for a gas-fired generator emitting 550 gCO2/kWh. Coal plants will be assumed to emit 900 gCO2/kWh, with coal at 15 million BTU and $100/ton delivered (average bituminous and sub-bituminous). Also, with the North American shale-gas investment bubble about to collapse and multiple LNG export terminals ready to push prices up to world levels, wholesale NG delivered to major markets costs $15/mmBTU.
This was worth working through in detail, so I posted the spreadsheet in both text and downloadable file at ergosphere.wordpress.com. This spreadsheet assumes a grid capable of delivering 600 GW average, to allow expansion for electrification of transport etc. I used a 20-year amortization for all RE generation (wind farm lifespan appears to be shorter than that), 30 years for nuclear (licenses are now being extended to 60 years), 7% interest rate, and highly decentralized and interconnected networks for both wind and solar generation. Without storage the RE must be consumed at the time of generation, so transmission capacity must equal peak generating capacity. I assumed cost of $2 million per mile for a ±1.2 megavolt, 1000 A (2.4 GW) dual-circuit HVDC line with an average of 1800 miles length between generation and market. That's enough to get Dakota wind power to the coasts, and Arizona and New Mexico solar power to both Seattle and Georgia. I also rolled in a $40/tCO2 carbon tax for the fossil-backed options, with emissions of 550 g/kWh for gas and 900 g/kWh for coal. In the all-RE case, some 2.3 million miles of HVDC line are required. Some of these may be able to share rights-of-way; some may not. This many times the total mileage of the Interstate highway system. I assumed for the sake of simplicity that fossil-backed RE could use DSM to use peak generation productively and would require neither storage nor spillage.
The cost figures for the RE options are all dismal. Gas-backed is cheapest at $114/MWh (11.4¢/kWh), with coal not far behind. The gas option emits 122 gCO2/kWh, which is at least twice what we can tolerate in the long term. Getting this down using storage is staggeringly expensive. Using the EOS zinc-air system at $167/kWh, total cost soars by a factor of almost 10 and power rises to a prohibitive 90¢/kWh.
The nuclear option comes in best. Assuming $5000/kW average for a new-build fleet of nuclear reactors (roughly twice China's cost for a new AP1000), and 180 GW (1200 GWh) of EOS battery storage, total capital cost is about $3.3 trillion. No HVDC network is required. Amortization over 30 years at 7%/year is $270 million. Total amortization cost comes to 5.1¢/kWh. Carbon taxes are zero, so the only unknown is O&M at perhaps 2-3¢/kWh. CO2 emissions from operations are ZERO.
The nuclear system does not depend on natural energy flows, so it can be expanded when and where desired. For each new application electrified on this grid, all the carbon it formerly emitted is displaced. This appears to be a cost-effective way to de-carbonize entire national economies.
This would be anything but a small task. 632 GW of AP1000's is 575 units, not allowing for refueling and repair outages. Even so, building 30 a year the USA could finish the job in 20 years. The alternative is to build something like SMRs, where we'd be turning out several a week instead of one every couple of weeks. That looks doable too.
Conclusion
Trying to de-carbonize the US grid with enough excess to electrify transportation is a massive task. The cost of the all-renewable scenarios for doing it, with the requirements needed to provide a reliable supply to dark/calm parts of the country, is prohibitive. Nuclear energy and the energy stockpile of fissile metals eliminates both the long-distance interconnections and massive storage needed for reliance on fickle energy flows. If we want to go green, nuclear is the only real option we have.
Labels: alternate energy, analysis, batteries, CO2, energy substitution, nuclear power, petroleum dependence
¶ 11/30/2013 01:16:00 PM 0 comments
Is the tide turning?
One of the more radical dreams of the true environmentalists (as opposed
to the anti-humanists who use environmentalism as a cover) is to convert
the world economy to renewable energy. They will not be fulfilled
until homes, factories and transport are using no fossil, nuclear or
other unclean, depletable energy supplies.This is a tall order, one that humanity has not met since the discovery of the useful properties of coal. Yet it remains worthwhile to keep the goal in mind, if not for the environment, then for our political and economic defense in the war declared against us by the Islamofascists. Randall Parker sets forth a standard by which we can measure our progress in one sense: when the alternatives to oil are cheaper than oil, the economic power of the Middle East will be beaten. Technology is unlikely to retreat, while depleted oil fields will never be more full than they are today.
The ideal scheme has always been the most expensive: the solar-powered car versus the status quo. Photovoltaic cells are one of the most expensive means of capturing energy from renewable sources, albeit also one of the simplest and lowest-maintenance. If a car receiving power from solar PV cells can deliver transportation at a lower cost per mile than gasoline, the millennium will have arrived. But could the millennium have sneaked in while we weren't looking? Let's take a look at the figures.
The beauty of electric vehicles is that most of the required infrastructure is already in place; we need no filling stations for new fuels or new pipeline networks. The new vehicle designs are ready to hand: we already have plug-free hybrid cars which attain 60 MPG and upwards, and if we add bigger batteries to such a hybrid we can make a plug-in hybrid or CalCar. More batteries does not just mean better acceleration and more efficient regenerative braking, it also means some operation without the need for any energy besides the stored electricity. We can build these cars today; we could (and should) have been building them ten years ago (but the litany of the sins of the California Air Resources Board is a rant for another day).
Suppose for a moment that we built such cars with today's technology and tried to power them as much as possible with renewable energy. How much would they cost to run?
The two major costs of the electric portion of such a vehicle are electricity and battery degradation. Let's start with batteries.
The current price-leader technology for storage batteries is the old, reliable lead-acid chemistry. It wins no prizes for energy density or lifespan, but it can be made for substantial power density and it is certainly cheap. Lithium-ion or fuel cells may be the ultimate winner of the technology race forty years hence, but if we can make things work with lead-acid we can get started immediately. We needed to get started in 1990, so we have no time to lose.
Depending on the chemistry and technology, batteries are limited by both cycle life and calendar life. If we take 3 years as a reasonable period between battery replacements in a car and assume daily use, we need approximately 1100 cycles from the battery if it is charged once a day and 2200 cycles if it is charged twice a day (say, at home overnight and again at work). If we refer to the cycle life vs. depth of discharge curve below, we see that if we want 2200 cycles of life we can discharge that model of battery by roughly 40%; if we only need 1100 cycles we can discharge the battery by roughly 50%.
Current electric vehicles consume roughly 200 watt-hours per mile. This seems to be a reasonable figure for conventional vehicles as well. If the vehicle is required to operate for 30 miles on electricity alone, it will require 6 KWH of electricity. At 50% DoD the battery pack would have to store 12 KWH, or 15 KWH at 40% DoD.
A commercially-available deep-cycle battery storing a nominal 1.2 KWH costs approximately $70 US at retail. If we assume that a battery equivalent to the Yellow Top can be built at this price, plus bulk discounts for production and purchase, we might see that drop to $60 or about $50 per KWH. A 12 KWH battery would cost $600; a 15 KWH battery would cost $750. The cost of energy storage for 2200 cycles to 40% DoD would be ($750/2200*6) = 5.7 cents/KWH; for 1100 cycles to 50% DoD, the cost would be ($600/1100*6) = 9.1 cents/KWH. The corresponding per-mile costs are 1.1 cents/mile and 1.8 cents/mile.
That takes care of the battery costs. What about the electricity to charge them? Solar PV panels produce DC, so it seems reasonable to assume a very high potential efficiency if they are being used to charge batteries more or less directly. Assume the net efficiency of battery plus charger is 80%, which yields 250 WH of PV output per vehicle-mile of travel.
The actual price of solar PV depends on too many factors to account for in an analysis this simple; however, the figure of $.25/KWH seems to be reasonable for the day. If we assume values from $.30/KWH down to $.20/KWH and run numbers, we get this range of projections:
If we assume wind or hydro power may be available at $.10/KWH retail, the figures look even better:
- $.30/KWH and 1100 cycles/3 years: 9.3 cents/mile.
- $.30/KWH and 2200 cycles/3 years: 8.6 cents/mile.
- $.25/KWH and 1100 cycles/3 years: 8.1 cents/mile.
- $.25/KWH and 2200 cycles/3 years: 7.4 cents/mile.
- $.20/KWH and 1100 cycles/3 years: 6.8 cents/mile.
- $.20/KWH and 2200 cycles/3 years: 6.1 cents/mile.
At this writing the retail price of regular unleaded gasoline is pushing $2.20/gallon in California. If the competition is a conventional internal-combustion engine vehicle burning regular gas at that price, I get the following energy costs for various levels of economy:
- $.10/KWH and 1100 cycles/3 years: 4.3 cents/mile.
- $.10/KWH and 2200 cycles/3 years: 3.6 cents/mile.
From the look of it, solar PV feeding plug-in hybrid cars can already deliver transportation to Californians more cheaply than any ICE-powered vehicle getting less than 20 MPG. If solar PV costs 20 cents/KWH and the vehicle runs its batteries for 2200 cycles between replacements, the cost is already par with a 35-MPG economy car. And if you assume the availability of wind or hydro power at 10 cents/KWH for charging, the plug-in hybrid can push energy-cost parity with the Prius.
- 12 MPG (typical big SUV): 18.3 cents/mile
- 16 MPG (typical medium SUV): 13.8 cents/mile
- 20 MPG (typical small SUV): 11 cents/mile
- 27.5 MPG (CAFE limit for passenger cars): 8 cents/mile
- 35 MPG (economy car): 6.3 cents/mile
- 60 MPG (2004 Toyota Prius, city rating): 3.7 cents/mile
It looks like the millenium may already be here. It's time to wake up and smell the coffee.
Cycle life vs. depth-of-discharge diagram for Yellow Top batteries.
(Graphic courtesy Optima, via Commuter Cars Corp. Copyrights NOT mine.)
Links and acknowledgements:
Costs of Oil Dependence: A 2000 Update
EPRI study on plug-in hybrid vehicles
Many thanks to the Institute for Analysis of Global Security, who compiled many of these links and did a fine job of documenting much of what I've been thinking about for the last several years before I found out about them. Also thanks to Randall Parker, who brought them to my notice.
Labels: batteries, hybrids, PHEV
¶ 3/13/2004 11:19:00 PM 3 comments
