South Australians have embraced solar power systems with a fervor, with over 30 percent of all South Australian electricity produced by renewable energy sources and a target of 50 percent by the year 2025. As solar systems produce energy only while the solar panels receive sunlight, the obvious ‘drawbacks’ include:
1. Homes cannot be powered by solar power at night
2. If the solar system produces power in excess of the homes electrical consumption needs then that excess energy is sent back onto the power grid and the owner of the system is recompensed for it at a rate (the ‘feed in tariff’) that is significantly less than the price paid for grid supplied electricity.
Storing Solar Energy
One possible solution is to have efficient and cost effective ways to store solar energy, produced by a homes’ solar system, so that is can be drawn upon in the nighttime to power the house. This offers the potential for homes to become totally ‘off grid’ – meaning that no connection to the grid may be necessary, or at least that the vast majority of a homes’ electrical supply needs could be met from its own solar generating system. Battery technology has long been used for ‘off grid’ solar systems, but these batteries have traditionally been ‘wet cell’ batteries (similar to the commonly used ‘lead acid’ car batteries) or ‘gel’ lead acid battery technology – where the battery electrolyte is suspended in a gel making the batteries more efficient and easier to handle. These type of batteries have had relatively low ‘energy densities’. Energy density is a measure of how much electrical energy the batteries can store within a certain volume. Obviously the higher the energy density the better. The other important factor in battery storage technology is its working ‘life’. As solar storage batteries are relatively expensive it is critical that their operating life time be significant. Battery ‘life’ is typically expressed in number of charge and discharge cycles and their life expectancy in years.
Lithium Ion To The Rescue?
Lithium Ion battery technology has been available for around 10 years but has emerged in recent years as the battery of choice where high energy density is required. The technology is used in mobile phone batteries, industrial back up power systems and medical electronics. Companies like Samsung have now developed lithium Ion batteries specifically designed for solar system usage. They have 2 Kilowatt and 5 kilowatt systems with specifications of 6000 cycles – giving (in our opinion) a realistic ‘life expectancy’.
A Game Changer For Solar?
Solar storage technology, in our view, will become a ‘game changer’ for the way South Australian’s eventually employ solar power. As this technology ramps up, the pricing to be able to store and then re-use that solar energy at a later date will decrease exponentially. Just as a 5 kilowatt solar system in Adelaide might have cost over $20,000 15 years ago, the same (or most likely, a technically superior) system now costs between $5500 and $10,000, the price of solar storage systems will inevitably fall significantly. This leads to exciting possibilities – when home owners will have a very real opportunity to become totally self reliant in terms of their electricity needs. Being able to run the home at night time from the power produced by our solar panels in the daytime will make sense economically, environmentally and will make concerns of ‘impending’ electricity pricing increases a thing of the past.