Storing The Future

Safe and reliable energy storage is a desirable goal for the PV and solar consumer and industry alike but despite technological progress in the field there has been issues around the cost and reliability of batteries for energy storage. Recent problems with batteries in Boeing airliners has done little to alleviate concerns. Clear Focus, based in Gloucestershire have announced new sustainable solar energy products specifically targeted to solar applications and believe they have solutions that will address consumer and industry fears. They are pioneers in the use of lithium phosphate technology in accordance. 

PV Plus, the solar energy backup and storage system from Clear Focus, stores power generated by the PV solar panels and captures it for later use. The technology presents the PV user with an opportunity to safely establish energy independence by providing a source of energy independent from the public grid. The lithium phosphate battery technology gained prominence in powering electric cars, as opposed to the more volatile lithium ion option, Ian Murray, technical director of Clear Focus, is a  pioneer in the use of lithium phosphate technology specifically for PV systems. 

"From planes to mobile phones, there has been increasing attention in the media on unsafe energy storage and the potential catastrophic results for both businesses and consumers." Ian commented. "At Clear Focus we develop solar energy solutions and we believe this product captures and retains excess power generated by almost any installed PV system of any size. It's our understanding that we have developed the first solar energy storage solution based on lithium phosphate technology."

"We have designed PV Plus for use with both commercial and domestic applications. From small to medium business of up to 35KW 3 phase to large domestic homes, the battery systems are available in sizes to cater for all purposes. The main benefit of this system is seamlessness of the automatic transition from grid operation to backup power, allowing systems to keep running with no power shortage."

PV installations reduce electricity bills after the initial installation electricity costs and FiT schemes allow businesses to be paid for the electricity that is generated. The government's feed-In tariffs pay the consumer for the electricity produced, even if it is used. Businesses can sell electricity back to the grid if the system is producing more electricity than is required, and now more importantly, PV Plus allows businesses to capture and reuse energy when needed, while also enabling any surplus to be sold back to the grid. PV also cuts the carbon footprint of any business: solar electricity is a green, renewable energy and does not release any harmful carbon dioxide or other pollutants. An average commercial solar PV system saves approximately 4 tonnes of carbon dioxide per year. More than 100 tonnes in its lifetime.

The lithium battery solar charge technology development and the PV Plus technology have run in parallel over the last 18 months. PV Plus is the solar storage unit which provides independent power and seamless automatic transition between the grid and the independent storage unit in the face of powercuts and shortages etc. Combining this with the lithium phosphate technology provides a premium, safe storage alternative to standard sealed lead acid batteries "“ providing a wealth of benefits including safety, stability, robustness in the face of damage and extreme temperature, longer life and green credentials.

Solar UK asked Murray to elaborate on some of the key elements of the new technology.

A: PV Plus provides an independent storage unit which stores power not consumed during the day and makes it available for use during night time.  It can be programmed to disconnect the building from the national grid and utilise its own independent power storage instead. It will also immediately disconnect the property from the grid if there are any power disturbances  "“ meaning no interruption to the power supply. This will enable almost every machine and electronic device to continue to function with no disturbance resulting in no downtime, data loss or inconvenience. Some existing storage devices either use a manual change over system or are not fully compliant with the UK's G59 standards and the local DNO's requirements.  PV Plus conforms and achieves the change over operation automatically meaning the user can sit back and not have to worry about turning switches or checking battery level. The automatic disconnect switch, safely removes the circuit from the national grid which has awarded us permission from Western Power Distribution.

A:The main challenge is creating intelligence that can manage and optimise the systems functionality automatically.  Understanding when the solar system is generating less or more power than the buildings demand and switching to use stored energy or not at the optimal times is the key. We are currently trialling existing systems which link to online weather forecasts in combination with the existing PV Plus system.  This is to test if increased online intelligence can improve the efficiency and economical benefits.  In addition, downsides in existing AGM lead acid based battery technology has shown during certain installations and in our opinion is the weak link in the systems long term reliability.  

Lithium based battery technology is where the development should focus. Our lithium phosphate option is also safer in many way, which include, no battery gassing during charging, a known problem using the existing technology, less effect to environmental change and longer lasting.  The down sides to lithium phosphate are cost and difficulties associated with changing from solar.  

A:Yes, very much so. The industry is highly regulated and  Electrical Safety is paramount in all developments Clear Focus undertake.  Gaining permission for a system design from the local DNO is a difficult and lengthy process. Solar PV and battery based backup systems are still a developing technology in the UK with increased understanding, for example with earthing, being gained year on year.  The metering of backup systems is also important to satisfy the utility companies as they will not allow the generation meter to be installed on 

the off grid side of the system. Essentially this means that  any off grid running time does not attract a FIT. This does not mean however that during grid connected times the Fit contracted is affected. 

A: Back up and energy storage is an increasing market within the UK, due to the Government predicted scheduled power shortages from 2016. It's crucial for the public to have power they can rely on. In addition, The more installed grid connected PV systems, the greater the strain on the local grid during periods of high generation. Germany has had experienced this very problem where increased grid voltages cause unwanted inverters disconnections, sometimes on a regular basis.  We anticipate this could become a problem within our network, PV plus can help reduce downtime. And allowing your system to run even if the grid supply is outside tolerance.  

Small Off grid power applications in developing countries are another area of investment and development which we have been working on. We take a national grid and easy power access for granted, but there is a need to develop remote systems for areas where power is a rare commodity.  Our brand new small lithium phosphate charge controller is designed for such an application.  It incorporates MPPT and an electrical circuit which will disconnect if for any reason the battery does become unstable was well as several independent outputs. It's a premium, cutting edge product that we hope will pave the way to a new standard in existing small off grid applications improving longevity and reliability. 

A: I predict a huge improvement in the intelligence of systems, sensing both the weather and patterns in the buildings load cycle, allowing optimisation of the system as a whole. I also think there is a lot of room for improvement in battery reliability and safety, which is why we have been endeavouring to develop our lithium phosphate technology. This is hugely superior to standard lead acid batteries and I'd love to see this become mainstream over the coming years as a viable green cost effective battery option.

A: There are so many benefits to using lithium phosphate batteries for any application and it's been a real triumph for us to have converted it into an option for solar storage. It is so much more stable and inherently safer "“ it's robust, it can withstand varying temperatures without performance being affected, it offers 90-100% usage of the battery capacity as opposed to 

50-60% with lead batteries so you only need to specify what you actually need. 

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