Saving Solar Energy For A ‘Rainy Day’
Because of the gradual reduction in the South Australian solar feed in tariff there is an increasing interest from prospective Adelaide solar customers for ways to maximise their return on the solar electricity that they produce from their solar systems. One area that is gaining increasing interest is in the area of solar energy storage systems. Because solar systems only produce their power during daylight hours, if a household does not use all of the electricity generated by the solar system, then the balance of the power (solar power produced minus the power used in the home) is ‘sold’ back to the electricity grid for a small sum, compared to the current price of electricity. Therefore being able to efficiently store excess generated solar electricity could be of great benefit to solar system owners. The other obvious benefit would be that the stored electricity can power all or at least part of the home during the night time (when the solar system produces zero electricity). Over the next few weeks we will take a look at current ways of storing solar electricity and new and emerging technologies
Solar Electricity Storage – Battery Technology
Traditionally, storage of solar electricity has been by way of battery banks. There are thousands of ‘off grid’ solar systems in South Australia, often in remote areas where grid supplied electricity is not available, or very expensive to establish, that employ solar panels in an off grid arrangement. An off grid solar system typically operated by wiring the solar panels into a charge controller which regulated the voltage from the solar panels to a constant voltage suitable for charging a battery bank. The battery bank then feeds into a suitable inverter which converts the 12 volts (or in some instances 24 volts) to 240 volts a.c. that is used in the home to power appliances.
Battery technology has come a long way and the traditional ‘wet cell’ lead acid battery has made way for gel electrolyte battery technologies that offer low maintenance, sealed encapsulation, meaning the risk of acid leaking or spilling is virtually non existent and these batteries offer relatively long life. The battery life is a critical factor in off grid solar system design as the cost of the batteries is relatively expensive and maximising the longevity from these battery systems is critical in ensuring maximum return on investment for the solar system as a whole. Factors like the design and quality of the battery charging circuitry and the ambient temperature that the batteries are stored at can have a very significant impact on the life expectancy of the batteries. Whilst battery systems have their place in solar energy storage there are new and exciting technologies emerging that could become a game changer for solar power in Adelaide. We will look at some of these technologies in the next update.