The Vale Energy System

About The Vale

The Vale is a 170 Acre farm in the NorthWest of Tasmania. It is located in a river valley in the shadow of Mount Roland.

Various crops are grown on the property along with the running of sheep and cattle. The property also features a large private runway.

We wanted to future-proof the property in terms of electrical energy self-sufficiency by building a large renewable energy system.

Here is what we built…

System Components

  • Three phase grid feed via a 500KVA transformer (configured for up to 200kWp export)
  • 100 Kilowatt Peak (kWp) ground-mounted solar array using 266 x LG 375W panels on Clenergy ground mount systems into 4 x 25kWp Fronius Symo AC Inverters
  • An additional 100kWp solar array (for a total of 200kWp) is currently under construction
  • Provision for future on-site generator
  • 144 kW / 180 KVA Victron Energy Inverter/Charger array (12 x Victron Quattro 48/15000)
  • 280 kWh of Flow Battery energy storage (28 x 10kWh Redflow ZBM2 zinc-bromide energy storage modules)
  • Victron Cerbo GX system controller interfaced to 3 x Redflow Battery Management System units
  • Underground sub-main distribution system servicing multiple houses, farm buildings and an aircraft hangar across the entire farm
  • Underground site-wide single-mode optical fibre network serving site-wide indoor and outdoor WiFi access points and networked access control and building management systems

A shout-out to DMS Energy in Spreyton, Tasmania. I designed the system with them, and they built it all extremely well. The installation looks great and it works brilliantly.

Here is a gallery of images from the energy system

Flow Batteries

The system stores surplus energy in Redflow Zinc-Bromide flow batteries. These are a product that I have had a lot to do with over a long period (including as an investor in the company and as the the architect of the Redflow Battery Management System).

These batteries have a lot of advantages, compared to using Lithium batteries, for stationary energy storage applications such as this one.

You can read more about them on the Redflow site and also in various other blog posts here.

System Performance and Future Plans

Tasmania is interesting as a solar power deployment area, because it has the distinction (due to being a long way south!) of being the best place in Australia for solar production in summer, and the worst place in the country for solar production in winter!

This was a key driver for the decision to deploy a relatively large solar array, with the aim of obtaining adequate overall performance in the winter months.

The large solar array is also a renewable transport fuel station!

We already run one Tesla Model S sedan, a Polaris ‘Ranger’ electric ATV, and an electric aircraft on the property.

Our plan is to progressively eliminate the use of diesel on the property entirely, by running electric 4WD vehicles, electric tractors, and electric excavators as they become available on the Australian market. The beauty of the large on-site solar array is that all of these vehicles can be charging directly from on-site solar generation when they are not being driven.

During this winter, we’ve observed that we typically manage to half-fill the battery array, and that it then lasts about half the night before grid energy is required.

That’s why we are now in the midst of doubling the size of the solar array. Once we have done so, we will have a system that (even in mid winter) can supply all of the on-site energy demands of the property on most days, without drawing any grid energy at all.

Of course, in summer, we’ll be exporting plenty of energy (and being paid to do so). Even with the relatively small feed-in tariff offered in Tasmania, the system generates a reasonable commercial return on the solar array investment in non-winter months.

Here are some (summer time) screen shots from the on-site control system and from the outstanding Victron VRM site data logging portal.

On the image from the on-site Cerbo GX controller, you can see a point in time where the solar array was producing more than 90W, the battery array was mostly full and starting to roll back its charging rate, and plenty of that solar energy was also being exported to the grid.

The ‘System Overview’ and ‘Consumption’ charts show the outcome of all that sunshine…with the battery ending the day pretty much full, the site ran all night on ‘time shifted sunshine’ and started the following day half full, ready to be filled up once more.

We exported plenty of green energy to our neighbours and we used practically no inward grid energy at all.

Once we have doubled up the solar array size, we are looking forward to achieving a similar outcome on most winter days, not just during summer, along with exporting even more surplus green energy into the grid.

Once we have transitioned all the on-site vehicles to electric, our total export energy will diminish somewhat, but it will be more than offset by a $0.00 diesel fuel bill (and by zero CO2 and Diesel particulate emission from our on-site activities).

On-site Energy Efficiency

One thing that matters a great deal is to do the best you can in terms of energy consumption, not just energy generation and storage. To state the obvious: The less energy you need to use, the longer your battery lasts overnight.

All the houses on the farm are heated/cooled using heat pumps.

This is the most efficient way to do it, by far. It is often poorly understood just how much more efficient a heat pump is, compared to any other way to cool or heat something.

That’s simply because a heap pump doesn’t create the heat – rather, it moves heat energy in the outside environment into the house (or vice versa, to cool it). Typical values for the Coefficient of Performance (COP) – the ‘multiplier effect’ between kilowatts to run a heat pump and kilowatts of heat energy that can be moved – are of the order of 3-4 times. That literally means that 3-4 times as many kilowatts of heating or cooling are created than the number of kilowatts of energy put into the device to do it. By contrast, heating using an electrical ‘element’ has a COP of 1, meaning there is literally no multiplier effect at all.

Because we’re in Tasmania, and it does get cold in winter, we have put in a wonderful indulgence in the form of a Spa pool. These obviously need a fair bit of energy to keep the pool water hot, and we have done two things to minimise that energy draw.

First, we have used a Spa heat pump to do the hot water heating, which accesses that fantastic multiplier effect mentioned above. It means we are heating the water by just moving heat energy out of the surrounding air and into that water.

Second, we have installed an optional monitoring and control device so we can access the Spa and remotely control it. We can turn the heating off when we are leaving home, and we can then remotely turn the heating back on when we are heading back, so it is nice and hot when we arrive.

We have a third heat pump at our home, the one that heats our hot water. We are using a Sanden Heat Pump based hot water system that (also) performs really well.

On-site Energy Monitoring and Control

The key to optimising energy usage is to be able to actually measure it.

The Victron Energy Cerbo GX at the heart of the energy system monitors all aspects of our renewable power plant in detail (and uploads them for easy review to the no-extra-cost Victron Energy VRM portal). This gives us fantastic (and super detailed) visibility into energy generation, storage, and consumption on site.

However, we have a lot of separate buildings on the farm, and the key to understanding and optimising energy draw is to get deeper insight into which buildings are using energy and when.

To that end, we have installed many Carlo Gavazzi EM24 ethernet interfaced energy meters all around the site-wide underground power network. At each delivery point into a building, there is an ethernet-attached meter installed, so that energy usage can be narrowed down to each of these buildings with ease.

I am currently working on the design of an appropriate monitoring system that will draw this data in and use it to provide me with detailed analytics of where our energy is going on a per-building basis (and when!).

In terms of control we have deployed KNX based sensor and control devices in a variety of places around the property, and we plan to deploy much more of it. Over time, we’ll be able to dynamically control and optimise energy consumption in a variety of useful ways.

KNX is a whole separate story, but – in brief – its an extremely good way to implement building automation using a 30+ year old standardised protocol with full backwards compatibility for older devices and with support from over 500 hardware manufacturers. It allows for the successful deployment of totally ‘mix and match’ multi-vendor collection of the best devices for each desired building automation monitoring or control task.

We are continuing to learn as we go.

With the upcoming enhancements in site monitoring and control, we expect to deepen our understanding of where energy is being used, to (in turn) allow us to further optimise that usage, using techniques as simple as moving various high energy demands to run ‘under the solar curve’ wherever possible. These are the times when on-site energy usage is essentially ‘free’ (avoiding the ‘energy round trip’ via the battery, and leaving more battery capacity for energy demands that cannot be time-shifted overnight)

Summary

Overall, this system is performing extremely well, and we are extremely pleased with it.

When we have added even more solar, it will do even better.

The #1 tip – even in Tasmania – is clear: Just Add More Solar ūüôā

The other big tip is to move your transport energy usage to electric.

The more electric vehicles we can deploy here over time (farm machinery as well as conventional cars), the better.

We’ll charge them (in the main) directly ‘under the solar curve’ and achieve a huge win-win in terms of both energy usage and carbon intensity.

As we keep learning and keep improving the monitoring and control systems… it will only get better from here.

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

Updated Feb 2019: System now operating at full battery capacity and with increased solar array size

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 – it also took ages to 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 50kWp 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.

Including that ‘floating’ 50kWp array, we have a total of 99kWp of solar on the site, though some of the rest of it is on ‘non-optimal’ roof directions, and so on a good day what we see around 80kW generated at peak in the high (solar) season.

That said, the advantage of some other parts of the solar system being on east and west facing rooftops is that our solar generation curve runs for more hours of the day. We get power made from earlier in the day (from the eastern array) and later into the evening (from the western one) – and that’s quite helpful in terms of providing a solar energy generation offset to local demand patterns.

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 bigger 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 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.

The battery array is built with 45 x ZBM2 = 450kWh of Redflow energy storage.

We have 72kWp of Victron inverters installed right into the container as well. We could have gone larger (in terms of peak inverter power), but these have been ‘right-sized’ to the building demand at Base64, with summer peaks normally around 60kW (75-80kW worst case) and typical draw around the 30-40kW level when the building complex is in daytime operation.

It is all linked to that 99kW distributed solar array using via multiple Fronius AC solar inverters.

I’m thrilled with how well the system is working – its a monument to all of our 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 programmable grid-supporting energy source during peak load periods. The missing links are software, regulation, and attitude – with the software part being the easiest of the three.

We can easily set up to proactively control over when the battery charges and discharges in response to, for instance, wholesale market price. The Victron control system makes that easy. ¬†What need to give that project legs is an innovative retailer who will work with us on that and a small amount of software ‘glue’ to make it happen on our local site.

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.

 

 

Why batteries will not cause mass defection from the grid

There’s a popular belief that the looming presence of batteries in people’s homes will lead to the widespread defection of those customers from the power grid.

In this view, living the dream means grid-independence where you harvest your own energy, one-finger salute the power companies and, when grid power fails for others in the street, your battery keeps the party going at your house.

While cutting the power cord sounds good in theory, in practice consumers gain many more advantages from staying connected to the grid.

Continue reading

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 Рand 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 ūüôā