Solar energy storage – getting the most out of the sun

Is solar energy storage possible? Energy from the sun has to be used as soon as it’s generated otherwise it is lost. However, if it is stored it can then be used when no energy is being produced – in the case of solar energy, this would be when the sun isn’t shining. Not only can solar energy storage systems enable users, whether residential or commercial, to get the most out of their solar panels – otherwise known as photovoltaic (PV) panels – but they can also cut costs, improve the efficiency of energy grids, and reduce carbon emissions and those of damaging greenhouse gases (GHGs).

Solar energy storage doesn’t just mean that surplus energy can be stored for later use when generation goes down and demand goes up. It also means that this energy can be used to smooth out any short-term disruption to energy supplies, such as outages, problems with generators or routine maintenance. A reliable solar energy storage system will enable users to keep their electrical systems running no matter what happens. 

This depends on the type of solar energy storage system that is used. Mechanical systems and batteries will often ‘leak’ energy when it’s being stored and released, so an accurate calculation is difficult. However, solar energy storage batteries can hold their charge for up to five days.

Essentially, there are three types of solar energy storage methods – thermal, mechanical, and battery.

Thermal energy storage systems use fluids, typically molten salt and water, to absorb and hold heat generated by the sun. The material sits in an insulated tank, and the energy is released when required – for heating, cooling or generating electricity (water is boiled by the heat, and the steam produced drives a turbine to create electrical power).

The goal of a mechanical energy storage system is to convert surplus electrical power into mechanical power and for this to be turned back into electricity when it is needed. One method uses a flywheel connected to a rotating shaft. The heavy flywheel is spun by surplus electricity and generates its own electricity for later use. Another mechanical method is pumped hydro, which pumps water upwards to a reservoir. The water then flows through turbines to produce electricity. A third mechanical energy storage option is to pump compressed air into huge containers and release that air to generate electricity.

Thermal energy storage systems can reduce CO₂ emissions and cut costs, but the energy can’t be stored or released at a constant temperature and a lot of energy can be used to convert solids into liquids. As for mechanical energy storage systems, flywheels can provide power quickly but can only store small amounts of energy, and pumped hydro requires access to large reservoirs which may involve building substantial dams and can be very costly to set up and operate.

By far the best of all solar energy storage methods are those that use batteries.

Solar power offers a sustainable way of delivering electricity to homes, offices, and factories for the future, but without solar energy storage systems, the full benefits of solar power can never be realised. As we know, there are many times during the day when solar production is at a low level but demand for energy is high. For example, in those dark evenings when energy is needed for lights or to power construction operations or events. In short, Lithium-ion energy storage systems enable powerful solar energy to be accessed when required rather than when it is generated. 

Photovoltaic panels can be expensive to acquire and install – actual costs depend on size of installation – so it is essential to draw out the maximum energy by connecting them to a solar energy storage system based on the very latest technology. This will ensure any photovoltaic installation operates as efficiently and cost-effectively as possible.