Renewable energy sources account for 11% of the world’s electricity generation, while solar energy accounts for a quarter of this share. But solar energy has vast potential to power the world. Energy scientists say that sunshine for one hour can power the globe for a year. The biggest hurdle in adopting renewable energy has been intermittency. Solar power generation is generated in waves; strong when sunshine is bright and low when there is no sunshine.
Energy Storage Solutions
The remedy to intermittency is a reliable energy storage solution. The best example is coupling a solar panel with a battery. When the solar panel is generating peak energy, it is directed to the battery for storage. When sunshine is weak or absent, the battery generates power.
Energy storage solutions are of different types:
- Batteries – They are the most common energy storage for personal, residential and small industry. They operate on electrolysis, where chemical interactions produce electric energy. There are non-rechargeable and rechargeable batteries. They are popular because they are cheap, come in varying sizes, and are portable.
- Pumped hydro- Water is stored in reservoirs and released to turn turbines that generate electricity. It is the most widely used large energy storage solution
- Thermal energy storage – Energy is stored as heat. The heat is released to heat water that runs electric turbines. Ice-based cooling systems work in reverse. Electricity is used to form ice. When cooling is needed, the ice absorbs heat.
- Compressed air – Electric compressors are used to pack air under very high pressure in underground containers. This compressed air can then be released to generate electricity using expansion turbines.
- Flywheels – This device stores energy as rotational kinetic energy. It spins at very high speeds up to 50,000 rpm to generate electricity.
Battery storage is preferred for coupling with renewable energy systems because it is easy to install and comes in customizable capacities. Energy output is instantaneous when needed. Batteries also come in varying sizes, which makes them suitable for powering up different devices. They can power small devices such as smartphones to large systems like electric vehicles.
Energy Storage Systems
The push to shift away from non-renewable fuel energy is getting stronger as more people realize the risks that come with climate change that has sped up because of fossil fuel emissions.
Today’s main renewable energy storage systems are;
- Hydropower systems – Water stored in reservoirs is released to run turbines for power
- Wind power systems – Moving wind is used to turn wind fans that rotate turbines to generate power
- Geothermal systems – Heated steam from deep underground is used to turn electric turbines for power
- Solar energy – Solar panels use photovoltaic cells to convert sunshine into electricity.
Why is Solar Energy Growing as the Fastest Renewable Energy?
Solar power is the fastest growing renewable energy storage system. In Singapore, the government has committed to growing installed solar capacity to 2 gigawatt-peak (GWp) by 2021. There is massive untapped potential for generating solar energy. For example, Singapore could tap 3.58 GW if solar panels were installed on 20,000 buildings. This untapped power is 10 times more than the current installed solar capacity. This power would be enough to power 75% of the residential homes.
There are several reasons solar energy systems are powering up more homes and businesses:
Solar Panels Have Become Cheaper
Solar panel costs have dropped drastically since the 1970s when the cost was about $35 per peak watt. By 2006 the price was around $3.5/W. The entry of multicrystalline silicon modules pushed the drop further to around $0.40/W. Solar experts expect this price to drop even further to $0.20/W.
Solar Panels have Become Better at Producing Power
Solar photovoltaic cell efficiency measures the ability of a PV cell to convert sunshine into electric energy. PV efficiency has risen from 8% in the 1950s to 14% in the 1960s, 20% in the 2000s to the current 20-25%. Photovoltaic efficiency has become a big research subject because 30% has been identified as a hard barrier to overcome.
Solar Panel Technology Has Become Easier to Install
Solar panels have become less bulky. Smaller panels with higher efficiency take less space, making them easier to install in crowded urban spaces. Crystal technology is the dominant material in solar panel construction, which has limited the efficiency of these types of solar panels.
Energy scientists are working with newer materials that are more flexible, thinner and of higher efficiency. For example, Perovskites have a thickness in terms of micrometers. They are thin enough to be painted on buildings.
Can Better Battery Technology Offer a Long-term Solution?
Bigger battery capacity is part of the answer to having a long-term energy storage solution. There are new battery technologies that are promising to provide batteries that can discharge for days or months.
A lithium-Sulphur (Li-S) is promising to deliver a performance that can power a vehicle for 1,000 km or power a smartphone for 5 days.
Silicon Anode Lithium-Ion Batteries
Scientists are looking to a li-ion battery that uses a silicone anode instead of a graphite anode. The anode will be made of hybrid measures silicon microparticles and carbon nanotubes. Silicon improves the energy density by up to 10 times more.
Cobalt Free Li-ion Battery
Cobalt is the cathode in many of the current batteries. It is expensive and damaging for the environment. A battery with a hybrid manganese and aluminum cathode promises higher energy density and longevity.
Why Do Better Energy Storage Solutions Matter?
Clean energy storage systems have a big role to play in powering up the world sustainably. They will produce energy at a more affordable cost while causing less environmental damage. There are many secondary benefits that will come from using clean energy.
Clean energy is part of the solution to mitigating the effects of climate change and the disastrous extreme weather events that are happening because of it. Elimination of fossil fuels also translates to cleaner air.
But the benefits of clean energy storage systems can only be realized if there are efficient and reliable energy storage solutions. Li-ion batteries are becoming longer lasting, while other battery technologies promise the same performance if not better.
Solar power systems with long-lasting batteries are the solution that has been around for a long time, but which have massive potential with the right research and funding. These two technologies will be essential in energy provision in the future, if their current adoption rate remains on the same trajectory.