T&D World Magazine
High-Flying Testimonial

High-Flying Testimonial

Solar Impulse is proving as it flies across the globe that microgrids are functional and reliable for extended periods.

As a long time electric utility veteran, I have always been attracted to power generation technology. I have followed the development during my lifetime of everything from high-efficiency turbines to various renewable technologies.  Renewables are particularly fascinating to me because they have a potentially limitless fuel supply, which is free.  Ignoring initial capital cost, renewables have great allure, with one (big) catch.  The fuel is not controllable in terms of when it is available.  Hence, the keen, almost dogmatic interest regarding the development and demonstration of cost-effective energy storage technologies.  Most industry executives interviewed today will say that energy storage is going to absolutely revolutionize the power industry.

I’m still mulling that over because we are still seeing storage projects of all kinds, including the historic storage workhorse of our industry, pumped hydro, failing for economic reasons.  That will be a discourse for another day.  Right now, as a renewables advocate for the right applications, and a technology nerd all the time, I have to say one would be hard-pressed to find a cooler proof of reliable 24-7 renewables operation than the Si2 Solar Impulse aircraft.  You may have seen press clips about this plane and Grid Ops has obtained and run a clip on the Solar Impulse partnership with ABB, which is available here:  http://tdworld.com/generation-renewables/solar-impulse-plane-shows-feasibility-100-renewables-certain-apps

The story is amazing.  This plane, powered exclusively with solar power, has already flown halfway around the world and intends to complete its journey circling the world this year.  The plane has broken records for solar flight duration and distance as well as pilot firsts with its one-man crew.  It has four electric motors (17.4 HP each) powered by 17,248 (66 Kwh peak) solar cells and four 41Kwh Lithium ion batteries.  According to Wikipedia, its wingspan of 236 feet is just short of an Airbus A380.  It takes off, flies and lands on its own power.

ABB, which has partnered with the Solar Impulse team in its quest to circumnavigate the globe to stimulate interest in renewable energy, likens the aircraft to an advanced, self-contained, mobile microgrid.  That works for me…so cool.  Solar Impulse is proving as it flies across the globe that microgrids are functional and reliable for extended periods. Conveniently, the Solar Impulse application also perfectly matches my perception of most microgrids today.  It is a uniquely designed package of generation, storage and control systems with a unique operation and maintenance scenario.  This microgrid is designed to be “islanded”, but many microgrids are designed for grid connection with islanding as a short-term option during specific circumstances such as grid disruption or maintenance.

While many of the microgrids we see domestically are fairly unique, the rationale for installing them usually falls in one of several categories:  achieving greater reliability or cost reduction.  Here too, the situations may be relatively unique; i.e., not something that will apply for the masses or at least not yet.  Another exciting example is where microgrid and renewable or other geographically unique resources can be used to bring power to remote locations. Solar Impulse Si2, true islands and areas of the globe not currently served with electricity are examples.

So how do we get from microgrids in relatively unique situations to a microgrid in every neighborhood and should we?  Undoubtedly, having microgrids connected to our distribution network is more complex than simply connecting distributed energy resources (DERs).  Microgrids may be a distribution planning challenge for utilities, but some would argue offer the prospect for greater system stability and predictability in the long run compared to DERs on a stand-alone basis.  Regulatory and business model challenges may also affect the propagation of microgrid applications.  However, at the end of the day, economics is likely to be the key factor.  While we are seeing great strides in cost reduction and technology improvements for renewables, DER and storage technologies, it remains difficult to provide service more economically than provided by most utilities, except in unique situations.  When that changes, it may be beneficial to have a microgrid providing some level of service in every neighborhood.

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