To fly a plane around the world on solar energy alone was considered almost impossible until Solar Impulse took to the skies last year, setting a new record for the longest non-stop flight*.
Claudio Facchin, President, ABB Power Grids division
The technologies that enable the plane to keep flying day and night have important applications on the ground, especially in places without grid connections or reliable electricity supplies.
Solar Impulse, which is resuming its round-the-world flight in 2016, is famous for having flown more than halfway round the world without consuming a drop of fossil fuel. What powers the plane is an on-board grid, which converts solar energy from the more than 17,000 solar photovoltaic cells that cover the plane’s wings and fuselage to power the plane. As long as the sun is shining brightly, the cells produce more than enough power to keep the aircraft flying, thanks to the plane’s exceptionally efficient electric motors. Excess power is routed to the plane’s batteries where it is stored for night flights. In this way, Solar Impulse can remain aloft 24 hours a day on solar power alone.
On the ground, self-contained power grids like Solar Impulse’s are known as microgrids, energy resources that are typically located at or near the place where energy is used and that operate in a controlled, coordinated way. They have the advantage of being quick to build and can operate either as stand-alone grids or be connected to the main power grid. In sunny or windy places, microgrids can be powered by renewable energy, such as a small-scale solar farm or local wind turbines.
Such microgrids lend themselves perfectly to island communities and remote villages and towns, which would otherwise have to wait years or even decades for a main-grid power connection. A notable example is the Azores island of Faial in the Atlantic, population 15,000, which has a self-contained microgrid powered by five wind turbines and six oil-fired generators. Others include the solar- and diesel-powered microgrids in the remote towns of Marble Bar and Nullagine in Western Australia. Thanks to grid stabilizing technology, which enables high solar-energy penetration, the towns now obtain close to 60 percent of their power from solar generation, saving approximately 400,000 liters of diesel and 1,100 tonnes of greenhouse gas emissions each year.
Microgrids have enormous potential in India and Africa, where more than 900 million people lack access to electricity. In sub-Saharan Africa, where two-thirds of the population – 620 million people – live without power, microgrids could dramatically speed up economic development. In India, they are likely to be the best solution for many of the 14,000 villages which the government has earmarked for electrification in the coming years under its “Power for all” initiative.
Microgrids also have important applications in industrial and commercial sites because they help to ensure power quality and availability. In cities affected by frequent power cuts, they are a clean and efficient alternative to diesel generators, which are highly polluting and expensive to run, pushing up the cost of doing business. In Kenya, for instance, 57 percent of businesses own generators. Microgrids that are connected to the main power grid also help to improve grid resiliency and reliability, for instance during extreme weather events.
Unlike Solar Impulse, which relies totally on solar energy, microgrids on the ground still depend on fossil fuels, such as diesel, for back-up power when the wind stops blowing or the sun goes down. However, thanks to advances in battery technology, it is now possible to store excess renewable energy, in much the same way as Solar Impulse does, further reducing the need for diesel.
For instance, a newly upgraded microgrid on Kodiak Island, off Alaska’s south coast, derives virtually all of its 28 megawatts (MW) of electricity capacity from hydropower and wind, supported by two 1.5 MW battery systems that take over as soon as the wind stops blowing. Similar solutions are being installed at two microgrids in Africa, one at ABB’s headquarters in Johannesburg, and another at a remote windfarm called Marsabit in northern Kenya, where the population of 5,000 relies exclusively on a wind- and diesel-powered microgrid.
As Solar Impulse and these examples demonstrate, the technology needed for the mass deployment of microgrids is now readily available. In addition, the cost of key technology components, such as solar photovoltaic and battery storage, will continue to decline as a result of the economies of scale and innovations in materials and manufacturing. Renewable energy is, in many cases, the most economical solution for electrification, with the levelized cost of electricity (LCOE) lower than diesel, provided the latter is not heavily subsidized.
Some countries have incentive-driven renewables programmes, but very often no framework specifically for microgrids. This is starting to change; the United States Department of Energy, for instance, is working to encourage the development and deployment of microgrids, and the Indian government is, under its “Power for all” initiative, promulgating federal and state policies to end regulatory uncertainty, which is in turn expected to unlock the level of investment required to scale up the industry.
With the right financing and business models that take account of the regulatory environment, microgrids could help to trigger development in rural areas, improving the lives of hundreds of millions of people, while helping to meet national and global emissions targets. We can run the world without consuming the earth.
*Solar Impulse pilot André Borschbergwas in the air for 117 hours, 52 minutes during his flight from Japan to Hawaii in 2015.
Claudio Facchin is the president of the Power Grids division of ABB Ltd., a $36 billion power and automation technology company specializing in power and automation technologies that enable utility and industry customers to improve performance while lowering environmental impact. The ABB Group of companies operates in around 100 countries and employs about 135,000 people.