Solar Impulse – the airplane created by Piccard and André Borschberg – already boasts eight world aviation records, including being the first and the only aircraft able to fly day and night without a single drop of fuel.
This seemingly impossible feat is achieved thanks to the 17,000 solar cells, covering 269.5 square metres of the plane's surface, which produce the electricity that propels Solar Impulse during the day. At night, however, it is the powerful lithium polymer batteries that keep the plane moving, driving Piccard closer to another record.
The most recent leg of Piccard's and Borschberg's solar journey comes after their quest had been put on hold for nine months last July, following the overheating of Solar Impulse's batteries during yet another record-breaking flight from Japan to Hawaii. Thus, the pilots were reminded of the greatest challenge in the realm of solar power – storing energy for a round-the-clock electricity generation. Determined to complete the mission, the Solar Impulse team shipped new batteries in and the quest continues with full speed.
In May this year, world environmental ministers will gather in Nairobi for the second session of the United Nations Environment Assembly (UNEA2) – the world's de facto "Parliament for the Environment" – to discuss ways of achieving the climate goals of the Paris Agreement and the 2030 Agenda for Sustainable Development. Finding ways of promoting innovation and technology transfer to address challenges such as energy storage, will be high on their agenda.
It is the exponential technological progress of the last decades that has led to a dramatic drop in the price of renewable energy. This has prompted governments to invest in clean energies and further research. For example, according to the recent Frankfurt School and UNEP Global Trends in Renewable Energy Investment 2016 report, India has invested $10.2 billion in renewable energy in 2015 – a 22 per cent increase from the year before.
In April, India's Minister of State with Independent Charge for Power, Coal, New and Renewable Energy, Piyush Goyal, acknowledged that solar power is now cheaper than fossil fuels. "I think a new coal plant would give you costlier power than a solar plant," he said.
Cognizant that the greatest challenge of using solar power is the capacity to generate electricity at night when demand for it is highest, the Indian Government is investing in innovative technologies to overcome such obstacles.
Innovative technologies such as the concentrated solar power plants under construction in Ouarzazate, Morocco which use solar power to heat liquid to fuel turbines that can produce electricity at night are just one of the many available options.
Another example, is the American Crescent Dunes power plant, which will open later this year. This facility uses more than 10,000 tracking mirrors to concentrate sunlight on a central tower where molten salt is used to store the heat, thus generating electricity around the clock.
In 2011, Nissan unveiled a system that enables storing electricity in lithium-ion batteries installed in their LEAF electric vehicles. Acting as a home battery, the car has enough capacity to run an average household in a developed country for more than a day. Still in the testing phase, the system has great potential for scaling up, as LEAFs are the world's most popular electric vehicles, with more than 200,000 sold as of December 2015.
Last May Tesla Motors unveiled their ambitious goal of changing the way we use energy. Similar to Solar Impulse, Tesla's battery is designed to store energy from renewable sources during the day and release it at night, when demand is highest. By reducing costs of its renewable energy products, Tesla is hoping to mainstream both its technology and the use electric vehicles.
Storing solar energy is just one side of the renewable energy coin. The intermittent nature of solar power, issues with power quality, voltage, frequency variations, power fluctuations and system stability all pose challenges to integrating renewables in national power grids.
Current electricity systems are designed to have more generation capacity than needed so that they can provide for spikes and to regulate the power frequency. This ‘spinning reserve’ requires keeping a number of turbine generators running on standby so that they can be brought on-line within minutes.
Meeting the peak in demand as described above can be very expensive. However, grid operators claim this is needed to compensate for the intermittent nature of wind and solar renewable energy sources.
A number of other companies are starting to challenge this paradigm, including the Berlin-based Younicos, whose company motto is "Let the fossils rest in peace." In September 2014, Younicos connected Europe’s largest commercial battery power plant to the grid for WEMAG, a supplier of electricity based in the northern German city of Schwerin, where it provides 80 per cent of electricity from renewable sources.
The commissioning of the company’s fully automated five-megawatt unit is the first time that a stand-alone battery is put to use in Europe to stabilize grid frequency, while safely integrating wind and solar energy.
According to Younicos, most power grids in Germany and other countries are stabilized by fossil fuel-burning power plants. This means that the grid can only use a fraction of its output to control power which in turn forces wind and solar generation to be taken offline.
In addressing the fluctuations in matter of milliseconds, the innovative Younicos battery system is a faster and more precise option than spinning reserve from a thermal power station. The company says its five-megawatt battery in Schwerin provides the same level of power for spikes control as a conventional 50-megawatt turbine.
All these remarkable innovative technologies are paving the way to make renewable energy more affordable and to effectively address the challenges posed by climate change. When the world's environment ministers gather for the second session of the United Nations Environment Assembly from23-27 May 2016, high on their agenda will be ways to scale up such innovations and transfer technologies to fight global warming.