The Duck Curve

In my business, this graph is known as “the duck curve,” and it’s a sort-of paradox. Home solar installations generate power when no one is home to use it, but then everyone goes home and suddenly needs power.

Where does the unused daytime energy go? Back into the grid in most cases, but then utilities must decrease output to match what solar customers are pumping into it. The other alternative is battery storage – either via things like Tesla’s “PowerWall” or by charging electric vehicles.

What most people don’t understand about the grid is that its total power must remain stable at all times. Even if the utilities are fully supportive of home power generation, the duck curve presents a challenge for them, because the more homes you have dumping power onto the grid, the more the utility must decrease its power generation to keep the total power precisely stable. And when everyone comes home in the evening, and solar generation decreases, the opposite must happen. All of this must happen in real time. Large fluctuations are harder to handle than small fluctuations, so more solar means means the challenge gets harder.

Because output fluctuates, renewable energy generation and battery storage go together like peanut butter and jelly – they must become tightly coupled. Now we just need cheap/light batteries to make it feasible everywhere. And so we can finally replace jet fuel with electric airplanes.

PG&E Home Energy Stats

Our energy provider is PG&E, though we opt-in to the MCE Deep Green program to ensure that 100% of the energy we use is sourced from wind and solar (it’s like having solar panels without having to own your own inverters). Went looking on PG&E’s web site last night to see how owning an EV has changed our electricity consumption over the past 1.5 years and was blown away by the quality of the data access and visualizations they provide. You can download billing and consumption data in CSV or XML for any date range, for import into spreadsheets or so you can build your own web app. But why bother? They offer a huge range of ways to view your usage data over time, to compare your usage to similar homes, to view electric, gas, or combined. They overlay weather data and plot-lines to help explain usage spikes. Super well done. You can fine-tune your home’s characteristics for better reporting accuracy.

The answer to my original question? Pretty much zero. Driving an EV has had negligible impact on our electricity consumption, which means I’m basically driving for free (though granted I sometimes take advantage of the charger in the work parking garage). Shown: How our natural gas usage increases in the winter months.

A Nation-Sized Battery

If you want to power your home entirely on renewables, the general recommendation is to include enough battery storage to keep things running for 3-4 days without any input (no sun, no wind). This fascinating blog post looks at a hypothetical scenario where we wanted to scale this pattern up to supply the entire United States with enough battery to back up a 100% renewable grid.

He does the math, and comes up with a battery size of approximately one cubic mile. Size is not a problem (it would be distributed), but the cost would be around $25 trillion – more than the annual U.S. GDP. And we know of no source in the world capable of supplying enough lead (he uses lead batteries in the though experiment because they’re 85% efficient and are the cheapest form of battery). So there’s some problem solving to do there, and there are problems with the hypothetical – for example the whole nation would never experience a lack of sun or wind for four days, and we could share extra juice around on a well-distributed grid, eliminating the need for this much battery storage. Or we could come to a fantastic battery breakthrough that changes everything. Or … Good read.

A Nation-Sized Battery

Fireside chat: Tim O’Reilly with Jason Calacanis

Loose notes from SXSW 2011 session: Fireside chat with Tim O’Reilly with Jason Calacanis

Jason Calacanis, Founder,
Tim O’Reilly, Founder/CEO, O’Reilly Media Inc

Wonderful way to open a week of stimulating sessions that challenge preconceived notions of technology, politics, and journalism in unexpected ways. O’Reilly was an intellectual silver bullet, as always, but really nice to catch him in an unscripted conversation rather than in one of his more “formal” talks.
Continue reading “Fireside chat: Tim O’Reilly with Jason Calacanis”

Waste Stats

Some really amazing figures on solid waste, via the Clean Air Council, including:

Only about one-tenth of all solid garbage in the United States gets recycled.

In the U.S., 4.39 pounds of trash per day and up to 56 tons of trash per year are created by the average person. [Since this is garbage night and this stat got me curious, I actually weighed our garbage tonight before taking it to the curb – a total of 2.5 lbs for a family of 3 – the rest was recycled or composted.]

Diapers: An average child will use between 8,000 -10,000 disposable diapers ($2,000 worth) before being potty trained. Each year, parents and babysitters dispose of about 18 billion of these items. In the United States alone these single-use items consume nearly 100,000 tons of plastic and 800,000 tons of tree pulp. We will pay an average of $350 million annually to deal with their disposal and, to top it off, these diapers will still be in the landfill 300 years from now. Americans throw away 570 diapers per second. That’s 49 million diapers per day.

Throwing away one aluminum can wastes as much energy as if that can were 1/2 full of gasoline.

Americans receive almost 4 million tons of junk mail every year. Most of it winds up in landfills.

As of 1992, 14 billion pounds of trash were dumped into ocean annually around the world.

Forty-three thousand tons of food is thrown out in the United States each day.

Each American exerts three times as much pressure on the natural environment as the global average.

People who change their own oil improperly dump the equivalent of 16 Exxon Valdez spills into the nation’s sewers and landfills every year.

… more at the site.

The Groaning Power Grid

Amid the din of conversations about how South Dakota alone gets enough wind to power a quarter of the country, or the huge efficiency gains of nuclear power, or how harnessing the movement of the tides could provide 20% of Britain’s energy needs, one important fact gets lost: The power grid in the U.S. has barely been upgraded in 20 years, and is nowhere near ready to move vast amounts of power across long distances. As energy demand rises and we start to look at large centralized installations (wind, hydro, nuclear, other), we overlook a politically inconvenient truth – without vast investments in the power grid itself, all that new energy isn’t going anywhere. The grid is already full-to-bursting, and moving lots of energy across long distances is a giant headache.

When the builders of the Maple Ridge Wind farm spent $320 million to put nearly 200 wind turbines in upstate New York, the idea was to get paid for producing electricity. But at times, regional electric lines have been so congested that Maple Ridge has been forced to shut down even with a brisk wind blowing.

“We need an interstate transmission superhighway system,” said Suedeen G. Kelly, a member of the Federal Energy Regulatory Commission.

Music: Rail Band :: Balakononifing

ServInt Goes Climate-Positive

Worldopener-Small Several years ago, when Birdhouse Hosting was young, I was researching the market to find a reliable datacenter that was entirely powered by renewable energy sources. I did find a few, but none working at the scale I was looking for (some didn’t have 24×7 monitoring and support; others did, but didn’t provide cPanel licenses). I ended up going with ServInt, and have been extremely happy with their reliability and support.

Today got some exciting news: ServInt has just announced that their whole VPS operation has gone not just carbon-neutral, but climate positive:

ServInt’s commitment to climate-positive hosting applies to its entire line of Virtual Private Server (VPS) hosting services. Each of ServInt’s VPS services is backed by a commitment to offset the total carbon-footprint of the VPS by at least 110 percent. ServInt accomplishes its carbon-offsetting goals through large-scale reforestation campaigns operated by American Forests (

To ensure a truly climate-positive approach, ServInt calculates its reforestation commitment not only on the energy consumption of the host servers, but on its entire VPS infrastructure. That includes compensating for all core routing and switching equipment, for cooling and redundant power operations, and for an extensive back-LAN that provides customers with free backups and centralized update repositories.

Music: Elbow :: One Day Like This

Integrated Manure Utilization Systems

The idea behind the Discovery show Invention Nation is good: Send three hipster dudes around the country in a bio-diesel bus, looking for interesting technological environmental solutions. Unfortunately, the show is poorly produced and executed, but the ideas in it are interesting enough that it’s kept me watching.

Cool to see a piece recently on Integrated Manure Utilization Systems (IMUS). There’s a butt-load (sorry) of usable methane gas locked in the manure that gets discarded by the ton at dairies and stock yards around the world. An IMUS system involves strategically placed floor grates in cattle yards, into which manure can be pushed. From there, it’s chopped, mixed with water, and placed in large holding tanks. Bacteria go to work on the sludge and methane rises to the top, where it’s burned (cleanly) to create electricity.

How effective is the process? The dairy farm visited by the Invention Nation guys had 250 cattle, and was able to generate enough electricity not only to power itself, but 150 average-sized households as well. And the equipment investment pays off in 5-7 years.

The Canadian Cattlemen’s Association says the range of benefits from IMUS include:

  • Reduced manure handling costs
  • Protection of water resources
  • Odour reduction
  • Recycling of waste water
  • Reduced energy costs
  • Value-added revenue from the sale of energy and bio-based fertilizer
  • Strengthening agriculture’s reputation of environmentally sustainable resource management

Imagine if every dairy and cattle yard installed their own IMUS – the enviro benefits would be immense.

Music: Son House :: Empire State Express

Turbine Turbulence: How to Fix U.S. Wind Power

Why is U.S. wind power output two million times below its potential, accounting for just one half of one percent of our annual consumption? (For point of comparison, Denmark currently gets 20% of its electricity from wind). Popular Mechanics sums up some of the challenges and potential solutions.

– Inconsistency. If the wind is blowing at night, and the grid is too full to soak up the excess energy while the town sleeps, a lot of energy goes to waste. And there’s no quick fix for a windless day. Batteries are the answer of course, but batteries make more sense for individual homes than they do for entire cities.

– The biggest wind farms are deep in rural areas such as North Dakota and Kansas, but it takes big pipes to bring the electricity they generate back to city grids. At a cost of $1 million/mile, no one wants to foot the bill. But all power sources need feeds to home-base, so wind energy should be taken into account along with other power sources when planning grids.

– Though an estimated terrawatt exists up to 50 miles off-shore, deep-sea turbines present their own set of problems – oil rig style platforms have to be enhanced to withstand the horizontal shear of blades as big as football fields, and floating them around is more complex than it sounds.

More info.

Music: Mercury Rev :: Hudson Lines