Fixing a Power Crisis with a Battery

Mira Loma battery facility, California

Last week the energy products VP of Tesla (supported by CEO Elon Musk) proposed the installation of 100 to 300 megawatt hours (MWh) centralised battery capacity in South Australia, consisting of banks of PowerWall 2 lithium batteries.

Based on figures from SolarQuotes, this represents a rough maximum of 37 to 111 megawatts (MW) of output for about 2 hours and 40 minutes. The amount of MWhs and MWs are very different quantities, routinely confused in commentary and the news; some articles have reported “100 MW”, and GetUp has appropriated the excitement in support of its questionable 100% national renewable energy ambitions:

Elon Musk has pledged to help fix South Australia’s power crisis by installing a 100 megawatt battery system in 100 days, or it’s free!

Exactly how it will fix a state’s power crisis hasn’t been quantified. The example cited in California, the recent Mira Loma facility (20 MW, 80 MWh):

will charge using electricity from the grid during off-peak hours, when demand is low, and then deliver electricity during peak hours to help maintain the reliability and lower SCE’s dependence on natural gas peaker plants.

Expert analysis of the broader Californian battery experience can be read about here.

While the excitement around the news was gripping social media on Friday, South Australian electricity demand looked like this:

The blue line is AEMO 30-minute demand data; the green line annotations simplify the day’s demand into an unseen bottom rectangle of baseload (1,200 MW for 24 hours: 28,800 MWh) and a peaky 7,200 MWh triangle corresponding to the normal daily demand fluctuation. Rooftop PV “behind the meter” consumption is added from APVI data, and is the estimated contribution from about 700 MW of total distributed capacity. The $/MWh price roughly follows this demand curve.

The advantages of battery storage are that it can be installed rapidly (regulations permitting) and can be switched on and off pretty much instantly. Based on the capabilities of a 100 MWh installation in South Australia, and the stated operation of the Californian example, no more than 37 MW could be suddenly supplied over the 2 hour 40 minutes of evening peak, as represented by the red line.

Does this look like it’s fixing a power crisis?

If this proceeds, the manner in which it will help keep state power prices from rising, or even begin to lower them, and how it will relieve the ever-growing reliance on South Australia’s interconnection with Victoria, must be primary considerations. As detailed in the SolarQuotes article, the 30% degradation in battery capacity from only 10 years of use and the limited operational lifespan thereafter needs to be highlighted: no other electricity grid infrastructure is expected to last such a short time. And perhaps most glaringly for many proponents, the potential environmental and social impacts from lithium production in other countries would never be tolerated here. If we’re were instead to pursue an Australian Made battery storage solution to our national power sector’s challenges, many vocal battery supporters need to work out why they prefer one massive foreign-owned hole gouged out of the earth to any other.

Greenbushes open cut lithium mine, Western Australia

 

Cooking the Comparisons

South Australia’s recent Nuclear Fuel Cycle Royal Commission examined many aspects of the complete fuel cycle, from mining to used fuel management and much in between. Considerable research was contracted to consulting firms. The task of comparing the economic viability of electricity generation in a mix of nuclear, gas and renewables was undertaken by DGA Consulting Carisway.

Sanmen AP1000 units in ChinaTwo nuclear options were included: a single AP1000 with a stated capacity of 1125 megawatts, and a six unit SMR plant rated at 285 MW (comprised of NuScale power modules of 47.5 MW each).

Various analyses were carried out to pit these nuclear options against gas and wind and solar, and the report’s details reveal the fundamental conceit utilised to shape the results: to ensure high value of wind and solar to the simulated scenarios, storage was assumed in unspecified but plentiful quantities which would smooth the output of these sources to whatever extent was required. Specifically, this was distributed batteries for rooftop solar (page 33), and grid storage paired exclusively with wind (page 34), justified only by the assertion that storage technology is advancing and will soon be economically feasible, alongside a reference to a newspaper article superficially covering laboratory work on graphene-based supercapacitors. The fact that one of the report’s authors is the chairman of a company connected to this graphene research – and an “international expert” in electricity grids based on high proportions of renewable energy and storage – is a minor detail compared to the absence of any accounting for the cost of this storage capacity.

Battery storage connected to rooftop solar has enjoyed spectacular coverage in Australia. As of the end of 2016, the closest thing to a guesstimate of current capacity is from page 34 of Solar & Storage Magazine – 31,000 installations, markedly lower than celebrated predictions of 100,000 from Morgan Stanley. But how much is this? If each installation is typified by the Tesla Powerwall, with a rated output of 2 kW and capacity of 6.4 kWh, then present distributed battery capacity in Australia might be about 62 MW and 200 MWh. It would take almost 5,000 times as much as this to fulfil the storage requirements in WattClarity’s 62 hour thought experiment.

In addition, the DGA report invokes an unspecified amount of vehicle-to-grid electric vehicle battery discharge to meet demand. This is now largely moot considering how complex and economically unviable it is understood to be.

oki07Recent thorough experience in california with proven battery storage technology at a larger scale – 2 MW, 14 MWh from sodium sulfur batteries – failed to demonstrate financial viability and anything close to the performance of the scheduled energy sources it is habitually touted to replace. Whatever the authors imagine to be coupled with wind in their models is even less proven. There are alternatives to battery storage of course, and seawater pumped hydro is often suggested, however the preeminent example – the distinctively octagonal Yanbaru plant on Okinawa – was this year decommissioned as uneconomical.

These criticisms are not intended to detract from the capabilities of battery storage technologies and their future roles. Storage should simply be respected instead of over-promised.

And why not allow nuclear output to charge these batteries in any of the modelling? The parallel analysis from Parsons Brinckerhoff also made reference to storage, and on page 19 observed:

…it should be realised that storage cost vs. benefit may well be more favourable for storage in a nuclear generation based systems than a renewable based system…

Without investigating the specific characteristics of South Australia, it is probable that the demand variability is more predictable than the supply variability. Since a nuclear-based system requires storage only to address demand variability, it is likely that the storage requirements to supplement a nuclear-based system and minimise the utilisation of fossil fuel-based assets is less than in a system that is highly renewable dependent.

The fundamental problems with the DGA report’s assumptions render it of limited usefulness, yet its ultimate shortcoming lies not in what it tried to achieve, but rather in what it intentionally didn’t. The modelled net present value of building and operating nuclear power stations was established as negative – unprofitable – when various market discount rates were assumed and applied to their costs. This isn’t surprising – reactors are up-front capital heavy, accruing expensive interest on associated loans, which nobody denies. When a lower social discount rate was applied (under direction from the royal commision) these projects abruptly flipped to profitable in all models (page 88). This lower rate is typical of government loan guarantees, public-private partnerships and straight-out public ownerships, which the authors surmise may be relevant if nuclear plants “were believed” to represent benefits for climate change action and the like which markets may not properly value.

There is no belief required here: it is simple scientific knowledge that nuclear energy is climate friendly. This fact has even been specifically supported in energy sector legislation in New York and Illinois this year. Unfortunately, the authors did not pursue the ramifications of finance-supported profitable nuclear capacity in their models and were content to let their chosen conclusions stand.

Yet, clearly this result should be the basis for further careful analysis of the economics of large modern reactors and small modular reactors in Australia, assuming that the recognition of societal benefits start promptly with the amendment of unjustified federal and state prohibitions. The current top-level review of Australia’s electricity sector can’t be excused from acknowledging the potential of using our uranium, not just exporting it, and where ultra-low emissions energy sources are to receive government support, this can be extended to nuclear with precisely the same justification. Indeed, on-going collaborative research by US National Lab experts in energy supply integration is revealing the benefits of supporting renewable and nuclear energy on the same grid.

nuclear-1_0

With the urgency that serious climate action and electricity sector reform deserves, evidence-led inclusive analysis should begin as soon as possible to enable Australia to imagine, transition to and enjoy a clean, modern energy supply.

 


Note 1: This critique is also not intended to detract from the commendable work of the Nuclear Fuel Cycle Royal Commission, which can be examined here.
Note 2: Quotes and table reproductions from the DGA Consulting Carrisway report itself have been avoided due to the disclaimer at the foot of page 2.

Storage in the Cold Light of Day

battery-deadPeople want energy in modern society when they want it, and so you’ve go to have supply and demand matching. And, again, there’s a new delusion that’s spreading through the world at the moment which is, “oh yes, now solar is coming down in price, wind is coming down in price, and batteries are coming down in price as well.” People seem satisfied with these simple statements: the prices are coming down so it’s all going to be fine, but they haven’t done the numbers to think through actually how big the batteries would need to be if you wanted to do a solar-and-batteries-only solution.

A solar-plus-battery solution in a place like Las Vegas, I can definitely see playing a large role… Society still needs reliability, though… Society stops functioning if we don’t have a reliable electricity system going all the time, and so for a place like Las Vegas you’re still going to want other technologies in that mix as well. So, I’d advise Las Vegas to get a nuke, for example…

I’m delighted how the book has been helpful… but I’m also still irritated that these delusions about the easiness of getting by with a bit of renewables and a bit of batteries… I think there’s still a lot more to do.

~ Sir David MacKay

It was a relief to hear that sensible projections regarding the role of batteries in Australia’s near-term electricity supply challenge were authoritatively expressed at the meeting of energy ministers last month:

The AEMO told the recent COAG Energy Ministers meeting it may be 10-20 years until battery storage would be able to exert an influence on grid stability and support.

There’s understandable disappointment from some commentators. However AEMO’s sober assessment merely echoes that of the CSIRO.

csiro

AEMO itself expects approximately 6.6 gigwatt hours of battery storage distributed amoung rooftop solar capacity by 2035-2036, which sounds like a whole lot more than exists now.

Yet, to get a sense of perspective, 6.6 gigawatt hours would provide no more than 2/3 of one percent of the 62 hour becalmed period described by WattClarity (with a hypothetical ten-fold wind capacity connected to the present national market).

The COAG Energy Council and its independent review process must maintain this realism as it strives to “maintain the security, reliability, affordability and sustainability of the national electricity market” and integrate climate and energy policy. This should encompass a technology-neutral approach, and recognise that avoiding consideration of the future benefits of modern nuclear capacity – potentially available on a comparable timescale to batteries, but historically proven – serves only a diminishing, out-dated activism, when we really have a whole lot more to do.

 

Storaging Your Way Out

This week, the long-awaited UK government approval for the construction of Hinkley Point C was granted. This will be a pair of modern light water reactors of the French EPR type, will generate 3,260 megawatts at full power, and has a design life of 60 years. An exhaustive description of the costs, subsidies and national context for this huge piece of energy supply infrastructure is available from the World Nuclear Association.

taishan-1-460-cgn

Taishan unit 1 in China will be the first EPR commissioned, early in 2017. Other projects in France and Finland have faced substantial delays and cost problems.

Inevitably, many will wonder if the 25.5 billion kilowatt hours and 14 million avoided tons of greenhouse gas can be achieved some other way – maybe even cheaper. Indeed, solar has already been advanced as a prefered option… by the UK’s Solar Trade Association. Just as inevitably, 1) this is solar plus storage, and 2) the amount of necessary storage isn’t specified.

This has already been dissected over at Energy Matters where it was estimated to be 7 billion kilowatt hours of storage capacity when relying on solar alone – “roughly the equivalent of eight hundred more Dinorwigs”. Dinorwig is the largest pumped hydro storage facility in the UK. Ironically, it was originally intended to store nuclear power overnight. Alternatively, it would take over 87 thousand of the largest battery storage installations ever proposed.

dinorwig

The devil’s always in the details. Especially when the details aren’t provided.

To be clear, solar plus storage still won’t provide what huge reactors do. And EPRs can’t provide anything like the flexibility of distributed solar/storage combinations. They have fundamentally different profiles, different scales. Since they can’t substitute for each other, it’s perverse to feed the persistent nuclear vs renewables struggle with them.

The Battery of the Gaps

Source: Lyon InfrastructureEarly in 2015 respected Australian energy market blog WattClarity put some simple estimates of required battery storage capacity for the NEM on the back of an envelope. To summarise:

  • Actual demand and wind data was used
  • Wind was low, mainland NEM-wide, for 62 hours
  • Median demand was set at 21,000 megawatts
  • The necessary electric vehicle battery capacity to fill the gap was gigantic at 1,271,000 megawatt hours (MWh)
  •  It was 992,000 MWh if the wind fleet were 10 times its current size

Since those three days of relative calm, to say that the hyperbole around the imminent triumph of battery storage has only escalated is an understatement.

But the assurances are invariably unaccompanied by arithmetic, and WattClarity’s calculations, like its technology agnosticism, remain as rare, much-needed examples.

But how many?

The assumption by many and the party-line for some in particular is that batteries will take the place of coal and gas as solar and wind dominate the electricity supply, pushing out the antiquated power stations. WattClarity’s estimates provide the basis for answering the inevitably absent question of how many?

2015March282930

(Blue: demand; green: wind; yellow: rooftop PV. llustration only)

But first, would solar capacity make a substantial difference? APVI records for those three days (28th to 30th of March) are incomplete, but assuming a calculated average 51% of nameplate output (1,876 MW) at noon maximum for NSW, QLD, SA and VIC, and generation from 6:30 am till 5:30 pm, solar supplies 10,320 MWh in total. Let’s multiply this by 10, like was done for wind, which provides daily peaks exceeding the average residual demand (16,000 MW), and as such the remaining nightly gaps of demand are reduced to a rough total of 682,800 MWh.

But how much?

Lithium-based battery technology, by far the dominant form for the foreseeable future, has dropped in unit price very rapidly. The AFR article linked above suggests a cost of USD $600 per kWh will be possible soon – which would today be AUD $798,000 per MWh.

Thus the necessary batteries on the back of this envelope cost on the order of AUD $545 billion.

But for how long?

10 years. We can be sure of that much. ESCRI-SA provides details on the expected 10 year lifespan in its on-going storage study, and this is consistent with the already impressive chemistry involved in lithium batteries.

To paraphrase Sir David MacKay, “I’m not anti-batteries, I’m just pro-arithmetic.” The ESCRI-SA project is fascinating, as is the innovative AGL virtual power station, and projects like Kingfisher present the cutting edge of aligning solar power with demand. But we’ve got to appreciate the scale here. We don’t have ten times the wind and solar as used for these thought experiments, and getting anywhere near it will be very hard work. And no amount of enthusiasm can overcome the reality of hard physical chemical limits to which the materials in batteries are immutably constrained – a given density will yield a certain voltage for a particular period, with no real reason to hope for a “big leap forward“. We’ve got to ask hard questions when batteries are proposed as the panacea to our very imminent energy supply challenges. Maybe just as importantly, we need to look at who is proposing it. Let’s evaluate all the options, from that sensible fulcrum.

To that end, there are already notable examinations of the potential value of battery storage. Crucially, they are not shy about including nuclear capacity in the analysis:

There is no silver bullet to decarbonize the electricity sector: the least-cost generation mix includes a diverse mix of resources and wind, solar, and flexible nuclear technologies co-exist in the optimal low-carbon generation portfolio, regardless of the level of energy storage. Under an emissions limit of 100tCO2/GWh, nuclear’s contribution to total energy supply ranges from 18–40%, depending on the amount of energy storage installed, while solar and wind shares are in the 9–15% and 23–43% ranges, respectively. Likewise, flexible nuclear contributes 52–68% under a tighter 50 tCO2/GWh limit while solar contributes7–14% and wind 12–19%, depending on the storage capacity.

The optimal energy capacity of bulk electricity storag (BES) turns out to be small in general, even when we impose ∼70% emission reductions compared to business-as-usual. The mechanical storage fleet was sized to supply the average electric load for one full day on its own. This value sharply drops as the energy cost increases while the power cost simultaneously drops; i.e. moving to electrochemical systems. These relatively low energy capacities signal the unimportance of large-scale storage of electricity over long time horizons (e.g. seasonal storage) from an economic point of view. This is driven by the lower competitiveness of BES systems coupled with wind in comparison to low carbon and dispatchable generation facilities, like CCGT and DZC (nuclear or fossil with carbon-capture) modeled here.

There are cautions from industry leaders like Ibedrola and Tesla, which should be heeded. Where pilot projects – like GRID4EU and Yanbaru – have not performed, we must understand why. Notwithstanding their lifecycle carbon intensity, storage technologies need and deserve rigorous and impartial assessment alongside our future energy sources, not and the disrespect of ceaseless, motivated oversell.

Emotion-o-meter2

Source: WattClarity