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Eclipse Effect on Mesa PV System

This is a plot of PV system output on August 21, 2017 in Mesa, Arizona.  Note the morning dip caused by the partial eclipse. The red line is the calculated average for the date, based on historical data.

Sonnen Signs a Deal to Put Storage in New Arizona Housing Developments

There is a point at which it will make economic sense to defect from the electrical grid

More than 1 million US homes have solar systems installed on their rooftops. Batteries are set to join many of them, giving homeowners the ability to not only generate but also store their electricity on-site. And once that happens, customers can drastically reduce their reliance on the grid.

It's great news for those receiving utility bills. It's possible armageddon for utilities.

A new study by the consulting firm McKinsey modeled two scenarios: one in which homeowners leave the electrical grid entirely, and one in which they obtain most of their power through solar and battery storage but keep a backup connection to the grid.

Given the current costs of generating and storing power at home, even residents of sunny Arizona would not have much economic incentive to leave the electric-power system completely - full grid-defection, as McKinsey refers to it -until around 2028. But partial defection, where some homeowners generate and store 80% to 90% of their electricity on site and use the grid only as a backup, makes economic sense as early as 2020.

This scenario is already playing out in Australia and Hawaii, and has begun spreading to solar-friendly markets such as Arizona, California, Nevada, and New York. As batteries get cheaper and better, utilities are rattled at the prospect of losing a massive share of their revenue.

A self-reinforcing cycle is at work. As consumers make their own energy, rates must increase on those left to cover the system's fixed costs. This raises rates still further, making it even more advantageous for customers to leave the grid.

Instead of adapting to this dynamic, utilities have generally sought to stifle solar with time-of-use pricing, demand charges, or cutting compensation for electricity exported back to the grid.

But as daily needs for many are supplied instead by solar and batteries, McKinsey predicts the electrical grid will be repurposed as an enormous, sophisticated backup. Utilities would step up and supply power during the few days or weeks per year when distributed systems run out of juice. Our analysis helps show the grid is very valuable as a backup investment, says Amy Wagner, a co-author of the McKinsey report.

Only, the business models of utilities are not designed for this. Their revenue typically depends on selling kilowatt hours: more electricity equals more money for utilities. Power users don't respond quickly to daily price spikes in their power bill, so ratepayers absorb electricity costs. That goes away in a world where software managing a grid connection can automatically switch to batteries to avoid high charges. A new business model is needed.

The only way to pay for the grid is as a network, said McKinsey's David Frankel, a co-author of the report. "It's very counter to what the industry has seen." Instead of paying per kilowatt, he suggests, grid users could pay for access and reliability, with one fee covering the vast majority of usage. The model might resemble the fixed, monthly charges we're used to paying for cell phone data and calls.

At the moment, only a tiny fraction of utility customers have left the grid or installed batteries. But it's happening faster than was expected several years ago. Solar panels and battery prices are dropping fast - lithium-ion batteries have fallen from $1,000 to $230 per kilowatt-hour since 2010 - as massive new solar and battery factories come online in China and the US. By 2020, Greentech Media projects, homes and businesses will have more battery storage for energy (841 megawatts of capacity) than utilities themselves.

Utilities may find they need to retool their business models sooner than they think.

From

https://qz.com/1017457/there-is-a-point-at-which-it-will-make-economic-sense-to-defect-from-the-electrical-grid/

Almost Too Much Wind Power in Europe

It’s Been So Windy in Europe  (June 2017) That (Wholesale) Electricity Prices Have Turned Negative

But we can't always rely on bad weather.

Editor's Note by the Arizona Solar Center:

This is one of the technical problems with renewable energy, sometimes the local utility (or even regional inter-tie area) will end up with more renewable energy than anticipated or useful.  For many reasons local utilities do not generate all the energy their customers need.  In the USA and Europe there are wholesale energy markets in which utilities and independent power producers buy and sell energy under contracts. There can be minimum and maximum power levels for specific time periods.  System operators need to maintain a balance of generation vs. customer loads (not a simple task), and must consider the varying load characteristics of the various generation sources. As a result some suppliers may be told not to supply contracted power (and may receive compensation as a result), and adjoining utilities may be paid to accept some extra power. 


It's been very windy across Europe this week (June 5, 2017). So much so, in fact, that the high wind load on onshore and offshore wind turbines across much of the continent has helped set new wind power records.

For starters, renewables generated more than half of Britain's energy demand on Wednesday—for the first time ever.

In fact, with offshore wind supplying 10 percent of the total demand, energy prices were knocked into the negative for the longest period on record. The UK is home to the world's biggest wind farm, and the largest wind turbines, so it's no surprise that this was an important factor in the country's energy mix.

"Negative prices aren't frequently observed," Joël Meggelaars, who works at renewable energy trade body WindEurope, told Motherboard over the phone. "It means a high supply and low demand."

Indeed, there were a few periods in recent days during which Denmark's supply of wind energy alone exceeded local demand—as much as 137 percent  overnight when demand was lower.

In total, around two percent of Europe's total energy supply was being provided by offshore wind on Tuesday.

"That's a very high level," said Meggelaars.

Producing more energy than your country can use isn't always a bad thing. It often simply means that energy can be sold on to neighbors, as is frequently the case with Danish supplies to The Netherlands, Germany and Norway.

The news comes not long after it was revealed that, worldwide, renewables supplied a record 161 gigawatts of electricity in 2016—and at a price that was 23 percent cheaper than it would have been in 2015.

Of course, one of the main features of energy sources such as wind that is made clear by this recent news is just how variable, or perhaps unreliable, it is. As a result, most countries still rely on more predictable sources of energy such as gas, nuclear, or biomass to provide their "base load"—the minimum demand on the electricity grid over time.

Source 6-8-2017 https://motherboard.vice.com/en_us/article/its-been-so-windy-in-europe-that-electricity-prices-have-turned-negative