CASE STUDY Our client farms which specialises in slow grown Longhorn Beef. Site owner identified that is is far more commercially viable to sell to the public. The challenge following a grid connection offer of 162,000.00 with a 12-18 month time scale meant his Farm Shop project was unviable. The site rural location with no electricity connection. The shop design energy efficient with modern freezers, fridges and LED lighting keeping the load to around 45amps peak single phase. The shop open Monday to Friday approximately 8-5 daily. Not occupied between 5pm Friday evening to 7.30am Monday morning.
LOAD PROFILE Single phase 45 amps peak Monday to Friday 15 amps peak 5pm Friday to 8am Monday morning 63 hours CRITICAL LOADS Freezers Security system Fire Alarm
SOLUTION 18Kva Single phase diesel generator with noise attenuation with a built in by pass function. 48v, 10,000VA dual input inverter with a built in 100amp battery charger 5 banks in parallel of 4 x 12v 150ah LEAD ACID AGM batteries ( C10 750ah total). Battery rack Cables and accessories Installation and commissioning At the point of design Solar PV was not an option and small Wind turbines had proved unreliable.
INDICATIVE COSTS EXCLUDING OPERATIONAL COSTS. Generator 7,400.00 Inverter 3,100.00 Battery 3,040.00 Battery rack 160.00 Accessories 75.00 Installation and commissioning 600.00 Total 14,375.00 net NOTE: Be spoke Lithium battery solution 26,040.00 net Modified domestic solution multiple strings 31,500.00 net
THE FORGOTTEN BATTERY, LEAD ACID AGM cycle life at 75% DOD 300 Gel cycle life at 75% DOD 420 In this instance a long duration battery was required with approximately 50 discharges per year. If the client decide to use the battery on more discharges i.e. nightly ( only 12 hour discharge) therefore avoiding the use of the generator even further then the diesel cost saving per year would justify replacing the batteries yearly. Lithium Ion cycle life at 75% DOD > 6000 Excellent cycle life capability but as the capacity market submissions have shown, Lithium lends itself to much shorter discharges 2-3 hour batteries maximum. Multiple cycles of short duration more aimed at balancing services such as EFR and FFR
THE FORGOTTEN BATTERY, LEAD ACID Battery life Lead Acid In this instance battery design life of 10 years is unrealistic as the battery would fail on number of cycles. Life would be up to 5 years. Life of the battery will be dependent on operating temperature. The site average ambient is 25 deg C and will not impact on this design. Occasional spikes in temperature do not impact on life. Battery life Lithium Ion Design life is quoted at 15 years and with the load profile would last well in excess of this. Many Lithium chemistries will experience degradation without regular cycles. Deviation from the manufacturers recommended operating temperatures does impact on cycle life and overall performance significantly.
Recycling Lead acid Fully recyclable Chemical materials can be disposed of safely without any special equipment or containers Manufacturers have a cradle to grave responsibility for the product Upon disposal a scrap payment may be found Recycling Lithium Must adhere to specific recycling requirements when available. Currently all products committed to landfill Cost of disposal currently 4-8 per KG
Safety concerns: Li-ion battery may explode when overheated or overcharged. Overheating or internal short circuit can also ignite the electrolyte and cause fire. This risk also subjects li-ion batteries to transportation restrictions, especially when shipped in larger quantities.
Protection required: lithium ion cells and batteries are not as robust as some other rechargeable technologies. They require protection from being over charged and discharged too far. In addition to this, they need to have the current maintained within safe limits. Accordingly one lithium ion battery disadvantage is that they require protection circuitry incorporated to ensure they are kept within their safe operating limits.
Sensitivity to high temperature: Li-ion battery is susceptible to the downside of too much heat caused by overheating of the device or overcharging. Heat causes the cells or packs of this battery to degrade faster than they normally would.
Aging effect: Li-ion battery will naturally degrade as soon as they leave the factory. This means that it is not completely durable despite longer charge-discharge lifecycle because of this normal degradation that transpires whether consumers use them or not. Storage in a cool place at 40 percent charge reduces the aging effect. Deep discharge: Li-ion battery has low self-discharge. The general integrity of this battery remains intact even if partially discharged. However, deep discharge or when the voltage of a lithium ion cell drops below a certain level, it becomes unusable.
Immature technology: Lithium ion battery technology is a developing area. This can be a disadvantage in terms of the fact that the technology does not remain constant. However as new lithium ion technologies are being developed all the time, it can also be an advantage as better solutions are coming available.
Smaller and lighter: Li-ion battery is lighter than other rechargeable batteries in consideration of battery capacity. This makes it more practical in portable consumer electronic devices in which physical specifications such as weight and form factor are considered important selling points. High energy density: Li-ion battery has higher energy density than other rechargeable batteries. This means having high power capacity without being too bulky. This is suitable for use in power-hungry devices such as laptops and smartphones. Advancements in technology open potential for higher capacities.
Low self-discharge: Li-ion battery also has a low self-discharge rate of about 1.5 percent per month. This means that the battery has a longer shelf life when not in used because it discharges slowly than other rechargeable batteries. Take note that nickel-metal hydride battery has a selfdischarge of 20 percent per month. Zero to low memory effect: Li-ion battery has zero to minimal memory effect. Take note that memory effect is a phenomenon observed in rechargeable batteries in which they lose their maximum energy capacity when repeatedly recharged after being only partially discharged. This memory effect is common in nickel-metal hydride rechargeable batteries such as NiCd and NiMH.
Quick charging: Li-ion battery is quicker to charge than other rechargeable batteries. It actually takes a fraction of time to charge when compared to counterparts. High open-circuit voltage: Li-ion battery has a chemistry that results in higher open-circuit voltage than other aqueous batteries such as lead acid, nickel-metal hydride, and nickel-cadmium. Longer lifespan: Li-ion battery can typically handle hundreds of charge-discharge cycles. Some lithium ion batteries loose 30 percent of their capacity after 1000 cycles while more advanced lithium ion batteries still have better capacity only after 5000 cycles.
Disadvantages of lead acid batteries v Lithium Shorter design life Lower cycle life Lower energy density Larger by at four times Heavier Longer recharge
In this instance Space was not a limitation Long duration battery was required, 50 hours plus Safety, site left unattended for long periods. Initial cost was a greater driver than lifetime costs. Lead acid batteries range from 0.8ah to 3000ah and can be paralleled with multiple banks allowing for a wide range of robust solutions. The modular solution we adopt means that multiple technologies can be included. Longer cycle life batteries are available using GEL Tubular Gel Lithium
WHAT'S NEXT? The site will now benefit from the installation of 4200 watts of solar. A bigger battery is being considered with improved chemistry A more robust wind turbine is being considered Remote monitoring will be added Continued monitoring of loads to ensure an optimum solution and clearly sized for the application and not what the market has available.
ALPHA HOUSE BATTERY SOLUTIONS 2V, 6V AND 12V AGM 5 Year design life 10 Year design life 2V, 6V and 12V GEL 6v and 12v Deep cycle AGM 6v and 12 v Deep cycle Gel High rate AGM UPS battery OPZV/OPZS range Long life block 15 years plus Battery Chargers Be spoke solutions for battery storage including Lithium and lead acid