The Role of Flow Batteries in Dispatchable Renewable Energy Grids

At the Australian Energy Storage conference held in Adelaide, South Australia on May 23-24 2018, I delivered this keynote address about the role of flow batteries and other energy storage technologies in the context of building an energy grid with renewable energy in the majority and with “Baseload” generation on the wane.

The core thematic question I posed was this: Is a future grid with large amounts of renewable energy storage necessarily using Lithium-Ion (or other, otherwise conventional) battery systems for the majority of that large scale energy storage – or are there better ways?

A specific underlying aspect of that conversation is about environmental impact – around the notion of ‘environmentally friendly’ energy generation and storage being a notion that must factor in the ultimate environmental impact for each storage technology and not just its up-front cost.

The video below is a recording of my address synchronised to the slide deck that I used.

The standalone slide deck is also available here: Hackett-Keynote-Redflow-AES2018

The Base64 Redflow Energy System

The Base64 energy system has been a fantastic learning experience for us in general and me in particular.

The system is built around a large Redflow ZBM2 battery array. We call these configurations an “LSB” (Large Scale Battery). It is charged with solar energy harvested from a large solar array (most of which is ‘floating’ above the staff carpark).

We deployed it first some time ago now, prior to having got so deeply experienced with using Victron Energy inverter/charger systems. At the time we (Base64) purchased a big custom industrial AC inverter that didn’t come with any sort of monitoring or logging system and no control system to drive it to interact properly with on-site solar.

All of the necessary energy system control, management and data logging technology comes ‘out of the box’ with the Victron Energy CCGX controller unit in a Victron installation,  so I imagined ‘everyone’ provided such things. Well, I was wrong about that.

The big industrial unit we bought came with nothing but a MODBUS programming manual and created a lot of head-scratching along the lines of… ‘now what?’. For some reason industrial scale systems are in the dark ages in terms of the stuff that Victron Energy have ‘nailed’ for the residential/SOHO battery market – they supply great, easy to use, easy to understand, effective and powerful out-of-the-box energy system control software and hardware (entered around their CCGX/Venus system). It also comes with an excellent (no extra cost) web-accessible portal for remote data logging, analysis and remote site system control.

Meantime, we were exercising our large battery ‘manually’ – charging and discharging it happily on a timed basis to prove it worked – but we were unable to run it in a manner that properly integrated it with the building energy use, for the lack of that control system in the inverter we had at the time. We didn’t want to write one from scratch just for us – that’d be a bit mad. We also didn’t want to pay someone else thousands of dollars to set up a third party control system and make it work – a major consulting project – just to do what the Victron Energy CCGX does on a plug-and-play basis at very low cost.

In parallel, and importantly – we also took ages to actually get substantial on-site solar operating at Base64 – and there wasn’t much point in driving the LSB in production until we did have a decent amount of on-site solar to sustainably charge it with.

To the latter point – we are in an massively renovated and reworked heritage listed building and I was unable to get permission to mount solar on the massive north-facing roof of the main building.

Instead we commissioned a rather innovative mounting system that has (at last) let us complete the installation of a big solar array that literally ‘floats’ above our staff car park on four big mount poles supporting what we call ‘trees’ – suspended metal arrays holding the solar panels up.

That system was commissioned and imported from a company called P2P Perpetual Power in California to suit our site. There are lower cost systems – but (by comparison) they’re ugly. We wanted it to be beautiful, as well as functional – because Base64 in all other respects is…both of those things.

It was worth the wait.

The result is (in my humble opinion) quite spectacular. We (at last) have a total of around 70kWp of solar on the site, though now I’m casting about to find some more ‘hidden’ roof spaces on the main complex where we might squeeze in just a bit more – you can’t have too much solar 🙂

In parallel, we pulled the LSB apart and rebuilt it using Victron Energy products and control systems, so that we could get a fantastic operational result and have optimal use of the solar energy to drive the building, charge the batteries, and support the building load at night – the very same stuff we do in houses with our batteries, just on a big scale – without facing a one-off software development exercise for the old proprietary inverter system we had been using.

Swapping the Victron Energy gear in has turned out far cheaper and far better than the bespoke software exercise would have ever been. It has also created a signature example of a large scale Victron Energy deployment running a decently sized multiple building site. I hope that this, in turn, may inspire more of the global Victron Energy installation community to consider the use Redflow battery technology at this sort of scale.

At the time of writing (January 2018), we have had 15 x ZBM2 batteries installed and running (150kWh total) for a few months now, with another 30 x ZBM2 units slated for delivery into the container later (its all wired up and ready for them). When installed, we will have a grand total storage capacity of 45 x ZBM2 = 450kWh.

There is 72kW of Victron inverters installed right into the container as well. We could have gone larger, but these have been ‘right-sized’ to the building demand at Base64, with demand peaks normally around 60kW and typical draw around the 30-40kW level when the building complex is in daytime operation.

Its all linked to a 70kW distributed solar array connected via multiple Fronius AC solar inverters. The main 50kW array is ‘floating’ above the staff carpark and the battery and the rest is distributed on other small, non-heritage, rooftop areas around the campus.

I’m thrilled with how well the system is working – its a monument to the last year or two of the Redflow BMS development work that the whole thing – at this scale – really is ‘plug and play’ with the Victron CCGX energy system controller and the associated inverter/charger equipment.

It is very satisfying to run an office in the middle of a major city that typically uses very little grid energy, that is resilient to grid faults, and that even still exports solar energy to the grid as well.

A subsequent step will be to interface with a grid energy ‘virtual power plant’ operator in the future, so that we can sell battery energy back to the grid during times of high grid demand. Every battery system on an energy grid has the potential to also become a grid-supporting energy source during peak load periods. The missing links there are software, regulation, and attitude – the technology part is easy.

Here is a little gallery of photos of the system that we’ve installed – click through them for a little more information about the system.

 

How State Governments can save money and drive the battery revolution

There is a great opportunity for Australian state governments to offer home battery storage incentives to consumers and to funding this incentive by repurposing existing, committed government expenditure. The mechanism I’m talking about is a voluntary trade-in offer, built around the residual payment stream for existing (and often very generous) solar Feed-In Tariffs (FITs).

These solar Feed-In Tariffs have already achieved their goal of kickstarting solar panel adoption in Australia. Indeed Australia is now among the world leaders in its per capita deployment of PV solar panels.

From a public policy point of view, continuing to pay solar Feed-In Tariffs well beyond the point where the underlying consumer investment in their solar installation has been fully paid off represents a substantial forward liability that does not deliver improved public good outcomes. However, state governments are clearly sensitive to the political risk of simply cancelling these long-running tariff schemes, some of which hold liabilities to as far as 2028.

However, Governments have an attractive way out of that problem, which serves both a public policy and industry development agenda while removing these long term liabilities from the public purse.

This involves inviting consumers to voluntarily trade in the residual life of their FIT in exchange for funding to buy a home battery energy storage system. This would have the dual benefit of eliminating a long-term forward liability for governments while kickstarting a home energy storage industry in Australia.

The remaining forward liability for a given customer can be readily estimated based on past subsidy payment patterns for that customer.

Past subsidy payment patterns are also likely to underestimate the remaining forward liability from the FIT schemes to governments. Each time a consumer reduces their home energy usage during daytime hours (through buying new and more energy-efficient appliances, installing automatic energy optimising control systems, and also through government-funded incentives such as this LED lighting replacement scheme), their future FIT payments from the government are set to rise still further in the future.

Accordingly, it seems likely that governments can likely save money overall by offering such a voluntary trade-in, even if the trade-in offer funds the entire capital cost of a home battery energy system. That up-front payment now could well be below the net present value of the (rising) forward liability of the FIT payments to the customer concerned.

Over the past year, Australia has emerged as a global battery proving ground because of its widespread deployment of PV solar panels and high electricity costs. Home batteries based on Lithium battery chemistries have been launched here by companies including Tesla, Enphase and Panasonic.

Redflow, an Australian company of which I’m Executive Chairman and a major investor, has recently launched its ZCell home battery, which is based on Redflow’s unique ZBM2 flow battery. This is a different kind of battery entirely. We believe it is far better suited to the long term demands and the daily ‘deep cycling’ required to store daytime excess solar energy generation and to let you use it to power your home at night.

The solar FIT buyout concept note here has been widely discussed in the Australian renewables sector and is reportedly under consideration by the Queensland Government. It has the virtue of re-using funds previously committed to kickstarting the PV solar panel sector to encourage the new home energy storage sector – with associated jobs and business growth.

Its important to appreciate that in many areas, the solar installation industry is now starting to saturate – with installers starting to struggle to find new growth areas in what has become a highly competitive pricing realm. The big opportunity for renewal in this industry is (now) the installation of battery energy storage systems in the same homes that have previously installed solar – but the high cost of battery systems at this early stage of the battery industry cycle is getting in the way. This voluntary FIT trade-in scheme could be just the growth catalyst the industry needs.

Just as with solar PV incentives, it will prove politically popular with citizens who increasingly regard home energy storage as a way to increase their energy independence and reduce electricity costs.

Widespread energy storage will also benefit far-sighted electricity companies by reducing demand during peak power periods and providing them with the possibility of buying home-stored energy as a ‘virtual’ on-demand power source rather than relying on fossil-fuelled driven peaking gas generators.

At a national level, widespread energy storage, both at the consumer and the grid level, will help Australia achieve its international carbon reduction commitments by time-shifting renewable energy so it can be used 24/7, not just when the wind is blowing or when the sun is shining.

Swapping solar Feed-In Tariffs for home battery installations is not just a win-win: It’s the gift that keeps on giving.

New Net, New Grid – FiRe 2015

In October this year I had the pleasure of having an in depth conversation about how the new energy grid and the new Internet grid is starting to evolve – and about the interesting similarities and overlaps that are evolving between the two.

A key thrust of the conversation related to the way that scalable energy storage is the transformative physical component driving changes in how the energy grids of the world will work in the future.

That conversation was undertaken between myself and Larry Smarr.

Larry was the perfect partner for this conversation. He is someone I have had the pleasure to have known in various contexts for some years now, and (as you will see in the video), we share some similar views on the topics concerned. I had a great time riffing with him on these topics.

The video of this conversation is available for your viewing pleasure here.

It is a 15 minute video that was excerpted from a half hour session at the Future In Review conference held in Park City, Utah in October 2015.

The Future In Review conference is pretty amazing – I’ve been a part of it for many years. This year I was (of course) wearing my Redflow hat loudly and proudly at the event 🙂