A note from Solar Choice:
Dr Larry Fingleton was one of solar power’s early adopters installing a 10kW ground-mount solar system back in 2009. Over a decade later he has now paired the system with a battery storage solution.
The below article is Dr Fingleton’s story and lessons he learnt from installing solar at his farm in NSW.
A solar and battery journey by Dr Larry Fingleton
The first thing to decide is how far you want to go. Assuming your house is already connected to the Grid, you have to decide how far you want to go to reduce the cost of electricity via that Grid Connection. It generally is based on an economic decision – the cost of the panels and batteries, plus installation and maintenance, versus your electricity bill. But the time to recuperate the costs is just as important. For some people, the minimisation of greenhouse gas emissions they are responsible for is a major factor, or the joy of putting into practice all your knowledge and interests.
The easiest way, and the most cost effective way, to reduce your electricity bill is to install solar panels. The number of solar panels you need depends on the amount of sunlight that falls on those panels, and how much you want to use your own power or the Grid’s power. The best economy seems to be to work on 4.5 hrs of generation (sunlight on panels)/ day for the year on average (summer and winter). Panels that move to face the sun versus stationary panels only need to be considered if the space for the erection of the panels is limited. It is a very expensive exercise, requiring long term high maintenance, compared to adding a few more stationary panels to meet the required generation. Roof mounting will usually allow enough space for sufficient stationary panels (all you can put on the roof anyway) and ground mounting (a definite consideration for a medium to large number of panels) always suffices.
Remember, nearly all electricity used at home occurs between 6am and 10pm and it’s a very simple matter to get a breakdown of your daily use via your Retailer’s Account eg. Origin Energy. Generally most power is consumed in the mornings with the sun up, and in the evenings with the sun down. With panels alone, you can get most of your power consumption into the daylight hours with some modification in your lifestyle, but winter heating and summer cooling at night will still be expensive. Hence the need for battery storage, hence the need for more solar panels to fill the batteries during the day. In the last few years it has become economically sensible to move this way and I will explain that with hard data (figures of costs etc.) shortly. But first there is one more consideration to mention – the reduction of energy needs.
It’s probably too late to have any second thoughts about the design, placement or orientation of the home building itself. However, insulation is vital – walls and ceiling (extra cladding), glass (double glazing), windows (proper fitting curtains), doors (sealed against air leaks), chimneys (closed in summer), isolation of disused rooms, and anything else you can think of. Type of Cooking (gas vs electricity – thermal or induction), Heating (passive vs active – wood, gas or electricity – various types available to be investigated by yourself if indicated), Cooling (passive – shading/ awnings vs active – fans or evaporative), Hot Water heater (gas vs electricity – conventional or heat pump) and Air Conditioning (standard electrical or combined Reverse Cycle heat pump/air con.). One very easy and cost effective means to reduce your energy usage is to change all the light bulbs to LED’s – they use much less electricity and last a hell of a lot longer. It is an easy way to get brighter lighting if required as well. We recently changed over our house from bottled gas (Elgas delivered to the farm house, with 5 large 45kg fixed cylinders, costing $2,000 a year) – running 2 hot water heaters, 2 free-standing stoves and a large lounge room gas (doubled flued, for sure) heater – to 2 heat pump hot water heaters, 2 Induction free-standing stoves and a large Reverse Cycle heater/ air con.). It wasn’t a cheap exercise but should be cost effective in 15 years, with savings on the Elgas and assuming electricity is neutral ( reduction with LED’s vs increased consumption of our “free” solar produced electricity). Even consider turning off as many “Standby” appliances as possible – said to be responsible for up to 8% of your electricity bill!
From your electricity Bills, averaged over 12 months, you will be able to calculate your own Average kWh/day. For example, a reasonable average usage would be 25 kWh/day. If we are saying there is an average of 4.5 hrs of sunlight/ generation per day, for the year (see paragraph 2), then we would need 25/4.5 = ~5.5 kW of solar panels – say 6kW. Remember, 6 kW of panels will give you a lot more than 25 kW on a summer’s day and give you nothing on an overcast winter’s day – and nothing at night obviously. Now, panels are being produced to give 350 W so to get your 6 kW you need 6000/350 = ~17 panels. Ground installation is best done in rows of 4 panels, so 20 panels will give you an extended range into shorter cloudy days. Panels now being produced are monocrystalline, compared to cheaper polycrystalline, which are much more efficient in low light and light falling at an angle onto the panel. All electricity produced by the panels is low voltage (< 10 volts) and DC. It needs to be converted to 240 volts/ AC by “Inverters”. Some panels can be purchased with Mini- Inverters on the back of them, at a premium cost, of course, so generally a Main-Inverter is placed back at the Battery Shed (if needed) or in a weather-proof box behind the panels.
There is some good news – the Government Solar Power Rebate. When you install a Solar System, a number of Renewable Energy Certificates are created. These Certificates (referred to as STC’s – or Small-scale Technology Certificates) are then purchased by Energy Companies as part of their Renewable Energy commitments. The value of these certificates can vary and either be deducted from the price of your system or sold (usually at a higher price) via the Clean Energy Regulator’s certificate Clearing House system. The system for trading and pricing STC’s for small systems is managed by the Small-scale Renewable Energy Scheme (SRES). Note: STC’s are also created if you purchase a Hot Water Electrical Heat Pump unit (see page 1). The current price on a STC is approximately $36, or roughly $600 per kW of Solar Panels eg. You get $7,560 rebate on a 12.6kW system. This reduces the cost of mounting 36 panels on the ground to about $30,000.
If you are lucky enough to live in the Hunter Region, there are some very interesting Interest Free Loans available for Solar PV and Battery Systems from the Government as well. Various T’s and C’s apply. Check all this information on energysaver.nsw.gov.au and energy.gov.au .
If you have an ABN for the farm business, and the business is run out of the house, AND you unfortunately have a large Tax Bill, you can claim up to $150,000 immediate tax deduction up to 31 Dec’20. It drops back to $30,000 pa after that time. Even with the batteries, you are only just over half way there! Secondly, if you are paying roughly $3,650 pa for electricity (25kW/day @ ~30cents/kW = $7.50/day, plus meter rental and standing charges of, say, $2.50/day, totals to $10/day = $3,650 pa.). In 20 years, you will have everything well and truly paid for, plus you will genuinely have free electricity and a very valuable asset (there all the time in those 20 years as well). Warranties on all the systems are:
Solar Panels………………….12 to 25 years
Inverters / Chargers…….5 to 10 years
Batteries……………………20 to 25 years
Figures I’ve been given, as a good way to look at the expense spread over 20 years, is…….. it costs 5c/kWh for Solar and 9c/kWh for batteries, giving 14c/kWh (including GST) compared to current cost of 30c ,or more, /kWh on the grid. If your electricity bill is greater than $3,650 pa, it won’t take the 20 years at all (and vise versa, of course). There are many assumptions and variables in these figures. Also, consider the situation of having $100,000 sitting in a bank account earning less than 2%pa. If you invert that in panels and batteries, you will get a saving of your electricity bill (say $3,650 minus standing charges to remain on the grid – about $600 pa), feed-in tariff (up to a few thousand dollars) and the asset itself (plus free electricity after all paid off).
Batteries in modern day usage, up to about 60 years ago, consisted of either car batteries (“lead acid” type) or torch batteries (zinc-carbon or alkali). Then came small electronic devices – watches and calculators initially – that needed better smaller batteries. These were developed from lithium – the lightest metal on the periodic table. This allows for the easy passage of a very small lithium ion through a lithium solution. Then an electrical current is applied to the positive (cathode) and negative (anode) electrodes – usually made out of graphite. Further developments changed the solution (the electrolyte) into a gel (or even a solid material lately), but they are all using the Lithium ion as the transporter of the electrical charge through a Lithium ion medium. Other changes were within the electrodes – the anode remained as graphite but the cathode was made/coated with all types of compounds (to improve the passage of the Lithium Ion onto the graphite). So, all Lithium Batteries are Lithium Ion Batteries – the passage of Lithium ions through a Lithium salt electrolyte.
Differentiation of the Lithium Batteries (with different performance, safety and cost characteristics) is due to the cathode – so we have Li Cobalt Oxide, Li Iron Phosphate, Lithium Manganese Oxide (LMO) and Li Nickel Manganese Cobalt Oxide (NMC). Most electric car batteries are NMC’s.
Relatively recently, a different approach has been adopted through extensive research. The anode is coated with Titanium Oxide instead of all other Li Ion Batteries (where the cathode is coated). This is still a Li Ion Batteries (LIB) – the electrolyte is a Lithium salt. To differentiate it from all other LIB’s, it is called an LTO (Lithium Titanium Oxide).
All batteries are made from a primary unit called a cell, which hare joined up electronically to form a battery. The cell is the base unit where all the chemistry comes together. All the cells are made in China. Nearly all are Panasonic, or their licensee, and most are owned to some extent by Warren Buffett. 99.9% of cells are made as “Lithium Ion Battery”- LIB. The other 0.1% of cells are made up of “Lithium Titanium Oxide”- LTO. These are the cells I have been involved with since their importation into Australia for my Batteries back in 2018. Our Company is called “Australian Titanium Power” and is the only importer of these cells. Nearly the whole world’s supply of lithium, and a lot of the world’s titanium, is mined in Australia. It is all shipped to China for refining and the production of cells for the electric car market.
The Lithium Ion Battery cells are tiny round cylinders approximately 18mm in diameter and 65mm long. Cylindrical because of ease of manufacture and also better power storage to weight ratio compared to prismatic ones. The various car manufacturers bundle these cells into flat batteries, requiring hundreds of connections as you can imagine, and these drive the electric cars. Once they fall to 80% efficiency, usually after 5 years, the battery is removed and a new one inserted – the power to weight ratio is no longer efficient for a motor vehicle. The old batteries are then broken down and the old cells are placed into battery boxes of numerous companies, and sold as Tesla Powerwalls, BYD Batteries or any other battery on the market (BYD is the best of this lot). Our LTO cells are also cylinders, but much bigger – 65mm in diameter and 165mm long. They are brand new when they are placed into our batteries.
- STORAGE CAPACITY AND CONNECTIONS
One LTO cell holds 40amps of electricity, compared to the LIB cell which holds only 4amps. So, 10 LIB cells need 20 connections to equal the same power storage capacity as one LTO cell – with just 2 connections.
This term means the number of times a battery is turned on/off. LIB cells cycle 10,000 times only, then stop working. If a car stops the engine and starts it again 5 times a day, after 5 years it’s almost useless (9,125 cycles). That’s a lot of stopping and starting but, if the cell has less than 3,650 cycles left when it is placed in a battery, its maximum life span at 1 cycle a day (turning on at night) is 10 years. You only get a 10 year warranty on a Tesla Powerwall/ BYD Battery. LTO cells cycle for 25,000 times – 68 years at the once a day rate!! And then it only reduces to 80% efficiency!! Hence a 20 year warranty.
Low minutes with LTO’s, hours with LIB’s. Temperature generation during charging: LIB’s get hot. LTO’s do not – however, due to such rapid charging, the Inverters may need to be cooled in summer.
Environmental temperatures have an enormous effect on the ability of these cells to take on charge. Both work well in the higher range, but at low temperatures there is a vast difference. LIB cells stop charging at 10 deg. centigrade (they have to be heated externally – mostly this is built into the battery or you would never get a car charged in Europe). LTO cells will still rapidly charge down to minus 20 deg centigrade. LIB cells are not heated in home storage batteries – hence not easily charged during most of winter. LTO cells do not need heating and so get fully charged in winter.
LIBs are flammable and somewhat unstable. These batteries must be erected on garage walls only (no habitable room wall can be used in a house) or else stand in an alone box, a meter away from the house in a fireproof container. They are responsible for horrific fires in car crashes. The LTO is non-flammable and can be chain sawed in half to prove its stability.
LIB cells/batteries are AC coupled, LTO is DC coupled. Apparently this means the technology needed to stabilize and monitor these cells is simpler in the LTO ones. Other technologies don’t really feature in this discussion talking domestic and small scale industrial applications. Flow Batteries are large scale and hydrogen has too many problems at this point in time – electrolysis doesn’t seem practical but hydrogen extraction from coal seems one to watch.
A LTO Battery is heavier than similar powered LIB battery. Hence there is a reluctance to take them up in cars – and what would you do with all the old LIB cells – and what cost to change over the Battery Production Line? LTO Batteries are used now in Chinese Buses. No overhead or rail electricity is needed. The buses are charged up when they pull into a Stop Station – a matter of only minutes. More and more, around the world now, the LTO cells are being used in all other forms of transport, solar storage and any other power production storage needed eg. small gas fired power stations in remote areas, temporary Military Bases, Mines, etc.
LIB Batteries have a 10 year Warranty, LTO Batteries have a 20 year & 25 year Warranty depending on the Model. Tesla, and I presume all LIB battery Manufacturers, have the ability to check on the usage of the battery over its lifetime. If at any stage, the battery is discharged to more than 60% capacity, your warranty is reduced to 5 years. If the discharge is greater than 80%, you have NO Warranty!! The ATP-LTO Batteries can be discharged down to zero without any problems, either to recharge back up or with the Warranty.
- FUTURE DEVELOPMENTS
There are 2 companies in China making LTO cells, almost identical as you can imagine. Further improvements have resulted in a 45amp cell (as opposed to the 40amp one we can source). However, China is keeping all those for itself and not exporting them (yet!). Any of these new cells testing at less than 45amps, eg. 44.9amps, is classed as a 40amp cell. So we should get some benefit there. Now, Tesla is all the talk at present. They are researching in America with an upgraded LIB cell that they are calling the “million mile” cell. There is no tech yet and very little detail, but the claim is, with these cells in their cars, they will be able to travel far greater distances between charges. Whether any of the other problems are also sorted out, we’ll have to wait and see. If they can produce this cell, they will then have to tool up in China for mass production. They will fill their cars first, so it will be many years away before it reaches the residential battery market. LTO technology are likely to advance as well.
When to jump in depends on what you want and how long you are prepared to wait – either for the technology or the returns!! I think batteries crossed over the line in the last few years to give a positive economic outlook, if you are prepared to take a long range view. Go for it!!