Energy storage getting real

Now that renewable energy sources like solar and PV are cheaper than new coal-fired power stations in most jurisdictions (anywhere with either favorable conditions or a reasonable carbon price), the big remaining question is that of supply variability/intermittency. As I’ve argued before, this problem is greatly overstated by critics of renewables who assume that the constant 24/7 supply characteristic of coal is the ideal. In fact, this constant supply produces a mismatch with variable demand and current pricing structures are set up to deal with this. A system dominated by renewables would have different kinds of mismatch and require different pricing structures.

That said, for a system dominated by solar PV, meeting demand in the late afternoon and evening will clearly depend on a capacity to store energy in some form or another. There are lots of options, but it makes sense to look first at relatively mature technologies like lithium and lead-acid batteries. Renewable News is reporting a project in Vermont, which integrates solar PV and storage.

The 2.5-MW Stafford Hill solar project is being developed in conjunction with Dynapower and GroSolar and includes 4 MW of battery storage, both lithium ion and lead acid, to integrate the solar generation into the local grid, and to provide resilient power in case of a grid outage.

The project cost is stated at $10 million, or $4m/Mw of generation capacity.

Assuming this number is correct, let’s make some simplifying assumptions to get a rough idea of the cost of electricity and the workability of storage. If we cost capital and depreciation at 10 per cent, assume 1600 hours of full output per year and, ignoring operating costs, the cost of electricity is 25c/KwH. There would presumably be some distribution costs, given the need to connect to the grid. Still, given that Vermont consumers are currently paying 18c/Kwh, this doesn’t look too bad. A carbon tax at $75/tonne would make up the difference.

How would the storage work? I’m starting from scratch here, so I’ll be interested in suggestions and corrections. I assume that the storage is ample to deal with short-term (minute to minute or hour to hour) fluctuations, which are more of a problem for wind.

How about on a daily basis? It seems to me that the critical thing to look at is the point in the afternoon/evening at which consumption exceeds generation (As I mentioned, prices matter a lot here). This is the point at which we would like the batteries to be fully charged. The output assumption suggests an average of about 12 MWh generated per day. If we simplify by assuming that the cutoff time is 6pm and that output drops to zero after that, the system requires that 8MWh be used during the day and 4MWh at night. That wouldn’t match current demand patterns, but if you added in some grid connected power (say, from wind, which tends to blow more at night) and shifted the pricing peak to match the demand peak, it would probably be feasible.

As regards seasonal variability, this would be a problem in Vermont, where (I assume) the seasonal demand peak is in winter. But in places like Queensland, with a strong summer peak, a system with lots of solar power should do a good job in this respect.

What remains is the possibility of a long run of cloudy days, during which solar panels produce 50 per cent or less of their rated output. Dealing with such periods will require a combination of pricing (such periods can be predicted in advance, so it’s just a matter of passing the price signals on to consumers), load-shedding for industrial customers and dispatchable reserve sources (hydro being the most appealing candidate, given that potential energy can be stored for long periods, and turned on and off as needed).

To sum up, we aren’t quite at the point where PV+storage is a complete solution, but we’re not far off.

130 thoughts on “Energy storage getting real

  1. Fran Barlow,
    I sunburn easily so I wear hats on sunny days. People used to be quite sensible about the sun and wear long sleeved dresses and bonnets etc. The film and fashion industries caused young people in the early 20thc to feel unfashionable doing so and the fashions became less protective from sun damage. And oil companies encouraged people to lather oil on themselves and get tanned skin. Anyway, sunbathing only potentially causes harm to the sunbather not a great many other people as well for many generations into the future.

    For your other examples – I gave never heard of us intentionally causing pathogens, earthquakes, bushfires, floods or tsunamis – the latter will increase with climate change which we are causing so we should stop causing it. I do not support research into biological warfare. The dangers and potential harms caused by Radiation we create intentionally is our responsibility. No one here would like radiation to be stored in their garden or likely even their and their children’s neighbourhoods permanently . I’m not convinced nuclear proponents like Will Boisvert would be so brave as to enter Fukushima like the technicians have had to – and the poor homeless people who were sent in to clear up the area. privileged people get other less privileged people to incur the harms of the risks they propose as necessary, including future generations. People try to get more privileged so they won’t bear the environmental injustices themselves and can live in pleasant neighbourhoods away from environmental risks. This is a big problem and injustice.

  2. Thinking about risk I began speculating as I began my journey home from work what would happen if we lived in societies that really did shape public policy according to risk. If Australia really were bothered by risks to human health one thing we would probably have done by about 1960 is phase out almost all private use of motor vehicles, at least in and between the major conurbations. The roads would be for the exclusive usage of people offering public transport, or who were using vehicles in the course of the provision of some service. These people would have to pass a character and competency test similar to that of pilots and they, or their employer, would have to pay very high fees for the use of the roads.

    It’s safe to say that in such a setting, road trauma and death would barely register in the stats. Our air would be damned near pristine, and respiratory disease would be a fraction of what it is today. Generations of kids would have grown up without lead poisoning and Australia’s CO2 emissions in transport would be utterly trivial.

    Our suburbs would not reach 50 km from our GPOs and public transport would be ubiquitous. Takeaway food would be an oddity and overweight and obesity would be unusual. Pretty much everyone would ride a bike to get around, and Australia would probably be a net exporter of petroleum. Australia would be winning awards in urban design and would probably be a leader in manufacturing public transport vehicles.

    Because the population would be living much more densely, we’d probably all have an NBN by now and without the burden of cars, all be a fair bit better off. Riding all those bikes, we’d probably have not found space to guzzle beer that much.

    And of course, if we’d simply prohibited smoking on the same grounds our health would have been better still.

    It’s an interesting counterfactual. πŸ˜‰

  3. @ZM

    I sunburn easily so I wear hats on sunny days. People used to be quite sensible about the sun and wear long sleeved dresses and bonnets etc. The film and fashion industries caused young people in the early 20thc to feel unfashionable doing so and the fashions became less protective from sun damage.

    It’s not only sunbathers who are at risk. Spend time outdoors and your risk goes up. Stay indoors and you risk Vitamin D deficiency.

    For your other examples – I gave never heard of us intentionally causing pathogens, earthquakes, bushfires, floods or tsunamis – the latter will increase with climate change which we are causing so we should stop causing it.

    I didn’t suggest we were causing the natural disasters, but that they seem less frightening because they are easy to process mentally, and people can imagine dodging them.

    Consider though: Hospitals use powerful chemicals to prevent spread of pathogens, but these chemicals are also toxic to humans. People clean their homes with chlorine to kill pathogens which are unlikely in practice to harm them anywhere near as much as the chlorine.

    Antibiotics are given to humans and farm animals which nurture antibiotic resistant pathogens. That’s rather perverse, don’t you think?

  4. I think natural seem quite frightening (except when I was young I always hoped it would flood – although we lived on a hilly area – so I could go boating in it – although we did not gave a boat). My community is not prone to earthquakes here, being inland and in the wrong part of the world also tsunamis are not a prospect. Occasional flooding is not too bad and mostly upsetting for reasons of property and infrastructure damage rather than danger to life because our creeks are not too big.

    But towns are surrounded by bush and people do worry quite a bit in summer, especially hot summers. There is quite a lot done to reduce brushfire danger, although the full recommendations from the royal commission are not being implemented by the government. Fires and flooding are to increase their frequency with climate change and I think a lot of people worry about this, since the fire season always is a concern. We also have a great many volunteer fire fighters and fire trucks and roads for fire truck access and water access for them. Brushfire preparedness certainly has room to improve, but people have definitely taken the risks seriously for a long while.

    I think doctors are meant to take care not to give out antibiotics unnecessarily. Hospitals have labour shortfalls, if they had more staff they could clean by sterilizing and scrubbing and so forth. They also waste more than they used to – a midwife friend told me maternity wards used to wash glass baby bottles, now they have plastic disposable ones. I do not really know much about how hospitals can be made more sustainable and keep safety and hygiene- someone would have to specialise in that area. Val might know more because she studies health promotion.

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