In this week’s solar news: Minigrids are key to resilience while, after a millennium of polluted air, London is finally breathing easier.

Microgrids are the next step in electricity efficiency

Once upon a time, we all got our energy from big coal-fired energy plants far away from where most of us lived. Our electricity came to us through high-voltage transmission lines strung over the landscape on the top of tall metal towers. We were all part of the same grid, and we didn’t have much to say about it.

Then the DERs arrived on the scene. No, DERs are not some dragon-like monsters. They are “distributed energy resources,” and they include technologies like solar panels, wind turbines, geothermal generators and energy storage tools like lithium-ion batteries. Sometimes, they are located much closer to end-users than large power plants. For solar customers, that can be as close as their rooftop.

As more residential and industrial developments build their own DERs, they also want to control the energy those DERs produce. Often, a microgrid is the result.

Solar energy and microgrids have a long history. One of the earliest projects is the Solar Settlement in Freiburg, a self-sufficient cluster of 59 residential buildings powered by solar panels which was named Germany’s most beautiful housing community in 2006.

Microgrids are just what they sound like—small versions of the huge infrastructure that utility companies own and maintain. They often include generation, storage, and transmission components and offer many advantages over just tying into a utility’s grid. They reduce the amount of energy lost in transmission, they allow for more efficient use of renewable energy, and they alleviate grid congestion.

Most of the time, a microgrid is connected to the local utility’s grid and exchanges energy throughout the day. But the biggest benefit is its ability to disconnect, which enhances resilience from outages. When an adverse weather event hits, a microgrid can disconnect from the larger grid and continue to operate.

Babcock Ranch, the Tampa area community that survived Hurricane Ian without an outage, has been in the news for its use of a huge solar array. But its other innovation—a microgrid—is just as important. Babcock Ranch’s solar panels produced energy, its batteries stored that energy, and its microgrid distributed it to residents while the surrounding area was blacked out. The community’s solar farm is attached to the larger grid—in fact, it is operated by Florida Power and Light. But when Hurricane Ian threatened the region’s grid, the microgrid disconnected and channeled its electricity through its buried cables to the community’s residents.

As is so often the case, California pioneered this technology in public ways. Jerry Brown advocated for microgrids during his inauguration speech as governor of California in 2015. He has since installed the next smallest thing, a nanogrid at his ranch north of Sacramento. As others in the state look to follow his lead, the state’s utility commission is currently is trying to settle on a regulatory structure for them moving forward.

America’s energy infrastructure was created with a much different power generation model than the one required for renewable energy. As smaller scale renewable energy sources become more prevalent, microgrids are just one more arrow in the quiver of engineers looking to create a more resilient energy structure.

London covered in fog pollution

London makes it too expensive to pollute

Sadiq Khan, was a finisher at the 2014 London Marathon just weeks before he was diagnosed with adult-onset asthma.

He blamed the city’s infamously bad air pollution for the disease.

Making London’s air breathable became a priority for Mayor Khan when he took office in 2016 and he even called air pollution was “the biggest public health emergency of a generation” In 2017.

London has long been known for its polluted air. The “London fog” made famous by Charles Dickens, Sherlock Holmes and a certain raincoat manufacturer has historically been pollution, not moisture. The city’s location in the basin of the Thames estuary means that pollution particles settle in its air and build up over time. In a five-day span in 1952, as many as 12,000 died from respiratory issues related to what is known as the “Great Smog.”

In 2019, the city implemented some of the toughest restrictions on polluting cars in the world. Now, London charges as much as $30 each day for diesel or gasoline powered cars to enter the city center. London had implemented a similar program in 2003 focused on urban congestion, but the fee was much lower and the restricted area much smaller. Mayor Khan’s policy focused on air quality and added a premium for gasoline-powered cars.

In the past three years, the number of electric vehicles in the city has skyrocketed. Internal combustion vehicles have become less common and NO2 levels, a key marker for air pollution, have fallen into the 1-2x range of World Health Organization guidelines.

One measure of the shift toward EVs in the taxi market. In 2019, Uber had just over 100 electric vehicles operating in London. Today, its fleet of 7,000 accounts for 15% of its trips in the city.

The area of the city that is subject to the restrictions is known as the Ultra-Low Emissions Zone, or ULEZ. In 2023, that area is set to expand to include more almost all of London’s 9.5 million residents.

The Weekly Sunsong

This week we are embracing Día de Muertos, or the Day of the Dead, a traditional Mexican holiday when families welcome back the spirits of their deceased relatives for joyful celebrations. Because we want that party to go all day and into the night, we’ve got more than a sun song, we’ve got a sun concert with Mariachi Sol De Mexico.