Two Weeks After Lift-Off

After a little delay our photovoltaic generator went online – we had been waiting for the delivery of this sophisticated addition to our office decoration:

Office Decoration

People on G+ had very cool suggestions, such as a rotating alien-fighting device throwing darts. Closest to the truth were: fuse box and fire alarm.

The box containing two knobs (actually this large box does not contain a lot):

Box with switches for PV DC cable

Two switches that are connected to that big red button downstairs, positioned next to the inverter for our PV panels:


We have two strings of modules, oriented perpendicular to each other; so irradiation on these is different. I add an overlay to a screenshot from Google Maps:

Plan of our house with PV modules.

Solar panels subject to different irradiance are connected in different strings – serial connections of modules; otherwise output power would suffer. The inverter has two inputs for two such strings and two MPP trackers that try to find the Maximum Power Point for each generator, by constantly probing each string’s current versus voltage curve.

Each string is connected to one of the little red knobs, which are part of yet another safety mechanism. The inverter converts DC current from the panels to standard 3-phase AC output voltage (230 V each phase). It has surge protection (another grey boy, but downstairs) and can shut off power at its DC and AC connectors – but then there is still a voltage drop across the DC cable from the roof to the inverter.

DC voltages supplied by our PV generators are about 400V, but generally they can be close to 1000V. This is a risk for firefighters connecting themselves to the circuit via a jet of water. You ‘cannot turn the panels off’ as long as there is sunlight! In order to make sure that the voltage drops to zero as close as possible to the panels, those switches are installed.

That ‘firefighters’ switch is semi-mandatory here. Lightning protection is not mandatory too, but we decided we should finally have one. Since safety standards and costs of such protection have grown exponentially in recent years, we can brag with a Faraday cage with tighter meshes and taller antenna-style tips than all our neighbours.

Alien EMP Protection

I am sure it protects us not only from lightning but also from alien attacks (see image below) and EMP guns – and the wiring goes well with the surface-mounted aluminium tube for the DC and AC cables for the PV generator.

Alien EMP Protection

The big red button is in the tech gadget closet on the left side of the driveway.

Firefighters will pull or push the red button in case of a fire. We decided for the pull option as you are less likely to pull than push something accidentally.

What we did not know before installation: The switch will also be activated automatically in case of a power outage – this means: about every 2 years for a few minutes. But when the big red button has been activated you need to switch power on again upstairs in the roof, too!

Normally, the switch box would be tucked away in an attic, above a dropped ceiling. We have no attic anymore – this is all office space, 3,5 high in the center. We could have squeezed the box into the insulation. But then after every power outage we would have needed to climb up there, remove roof tiles and switch on power again. So we spontaneously decided to have it installed on the ceiling, above the Chief Engineer’s desktop:

Office Decoration

Last Monday The Metering Guy from the utility finally installed a smart meter, capable of metering both consumption and feed-in to the grid. He had to disconnect from the grid to do so. We switched on the inverter in bright daylight – and there was no power! Panic – what happened? I fetched the laptop and the inverter’s manual, ready for troubleshooting – until The Chief Engineer walked by, carrying a ladder, and grinning mischievously:

Have you perhaps triggered the firefighters’ switch when disconnecting from the grid?

I had forgotten about the switch only about 15 minutes after I putting big signs for firemen! But at least we knew it worked!

After one more controlled test of a power outage we were finally online. This is what power generation looks like on a nearly perfect sunny day now (2015-05-11).

PV Power over Time, 2015-05-11

Since May 5 we have consumed 11kWh / day on average; about 55% of this have been provided directly by the solar panels. Daily energy generation was about 23kWh; we used 27% of the power generated.

“An Unprecedented Test for Europe’s Electricity System”

And we will not be able to contribute – by a hair. We have just ordered our photovoltaic generator, and installation is planned for April.

It is the (partial) Solar Eclipse on March 20 that made Europe’s Transmission System Operators (TSOs) release an announcement:

Under a clear morning sky on 20 March 2015, some 35000 MW of solar energy, which is the equivalent of nearly 80 medium size conventional generation units, will gradually fade from Europe’s electrical system before being gradually re-injected: all in the space of two hours.

Managing this event on the world’s largest interconnected grid is an unprecedented challenge for European TSOs. Solar eclipses have happened before but with the increase of installed photovoltaic energy generation, the risk of an incident could be serious without appropriate countermeasures

This paper shows the grid operators’ model and calculations.  20 GW would already correspond to a shift in frequency of 1 Hz – which is huge (from this German article on control mechanisms in the EU power grid). The TSOs’ benchmark is the speed of the  sunrise / sunset, and the solar eclipse’s shadow is faster.

I mentioned before on this blog that I think the power grid is a remarkable and most underestimated achievement in engineering as well as in the design of associated financial markets. In every single instant supply and demand of power have to be balanced exactly – so turning on and off an appliance immediately has to trigger a change in power provided by generators.

Grid operators today emerged from the split of monolithic power companies that integrated both power generation and distribution. Monopolies run by government, allegedly privileged and maybe as ‘popular’ as the stereotype ancient evil telephone company, emerged into a set of distinct players – operators of power plants and operators of the grid. They are now part of a complex market comprising also consumers, different kinds of traders, and agencies. Regulators needs to make sure that there is both fair competition and safe supply of electrical power to anyone in the long run.

For decades the grid had to deal with centralized, large generators only, and both the physical infrastructure  and the smartness of control systems needs to be continuously adapted to deal with a huge number of small, dispersed generators whose output is volatile. Commentators stated that unbundling of grid operations and power generation  caused players in the market to focus on their individual goals whereas ‘thinking holistic systems’ in not fostered anymore.

So TSOs might be concerned about the rapid increase of the number of generators of renewable energies as they are not the ones profiting most from energy sold anymore (their fees are regulated), but they need to care for safe and reliable distribution nonetheless. The development of the smart grid had been called the largest global IT infrastructure project ever – and this is perhaps not even doing the electrical engineering part justice. In Europe nearly all homes need to be equipped with smart meters until 2020 – which is a challenge given restrictive data protection laws and logistics.

It is  impressive that German TSOs can handle this today in such a reliable fashion:

Electrical power from different sources in Germany.At noon more than one third of power generated – about 20 GW  –  can come from photovoltaic generators, and some of that has to be exported to other countries. But this has to be compared to energy generated, that is power integrated over time: About 6% of all energy generated in a year is from solar generators – 32,8 TWh (Solar power in Germany, data for 2014).

Since a year has 8.760 hours, the average power is thus

32.800 GWh / 8.760 hours = 3,74 GW.

So the average solar power is only a fraction of peak solar power. And this is, unfortunately, why we should not over-hype record powers in solar energy generation. The challenge of the near future is storing, intelligent re-distribution, and management of consumption of electrical energy.

Personal Risk Assessment

We all do risk management intuitively – when we decide on uploading our data to the cloud where the NSA may spy on us. Or when we install heating systems that depend on electrical energy. The previous post triggered an interesting discussion about the risk of a power outage.

Is it more risky to pick a heat pump – compared to other systems?

In Austria, nearly all private homes use central heating systems and thus rely on circulation pumps – no matter if you run a natural gas boiler, a wood pellet burner, or a heat pump. Heat is distributed via hot water, powering floor loops or radiators. Heating circuits powered by gravity only are hardly installed today. So a heat pump system does not score worse in case of a power outage. It might hurt even more if you have a cellar full of wood pellets or a tank full of fuel oil – but you cannot get the fuel or the heat to the place where you need it.

You might also compare heaters of the same level of convenience – heat pumps would compete with natural gas boilers that don’t require storage facilities for fuel but access to a grid. I am concerned about gas pipelines traversing countries that make headlines periodically because of the next political gas crisis. But I am less concerned about electrical power – this is the view from our office:

Wind turbines seen from the office

In Austria the average power outage per utility customer and year is less than 1 hour. We had an outage of about half an hour every few years. There are no issues with cable nibbling squirrels, and we worry more about hackers attacking the grid than about breakdowns.

But experts in disaster management tell us that we rely too much on highly available power. This is called the Vulnerability Paradox: The more dependable a service is, the less prepared you are for outages. According to a recent study anarchy will reign a few days after a large-scale blackout in Germany: Police would not be able to refuel their cars as modern gasoline pumps don’t work without power. Sewage systems and toilets would not work.

The impact of ‘just’ not being able to heat might be less dramatic. The lowest average daily ambient temperature here, in Eastern Austrian lowlands, is -12°C. We have encountered it on 4 days in 20 years; the lowest minimum was -17,8°C. If power would be cut off for a day in winter the temperature will fall by a few degrees only. It might irk me more if our internet connection is down for this period of time.

And many Austrian home owners have a backup strategy that blends with aesthetic preferences. Artisanal tiled stoves are popular here:

GrundKachelofenLocal building code demanded us to have an emergency chimney – so we installed the Free Flow Bullerjan stove shown below. I learned now from the company history that it had been invented in Vermont and built in Canada before it became a viral hit in Europe. It can heat our 110m2 open space second storey just fine:

Bullerjan stove

Now why not using a traditional stove for each room as the only heating system – to be independent from the grid all the time? If nobody is at home for several days to put wood on the fire the house will cool off. This is not only a risk, but it will happen with 100% probability, e.g. if you travel for business often.

What happens if power is cut off for several days – and we are traveling? I think the probability would be lower than the likelihood of a tractor crashing into the wall of our house – which is actually a risk listed in our home insurance contract.


Heating 2003 to 2012 by fuels used and heating system (in Austria). Less than 15% of (primary) heating systems are stoves, and they have been on a decline in the last decade. (Link got broken, fixed with new link: 2015-06-04)

Greatest Innovation Ever

I like silly Top Something Lists. In a more serious state of mind I wondered what a list of the top inventions or top innovations of humankind might comprise.

Random googling yields list items such as The Internet, Money, Plumbing, and The Power of Story.

This list contains what my biased mind was searching for: Electricity, Water Power, The Light Bulb, The Steam Engine, The Electromagnet, The ElectronSemiconductors, The Transistor, and of course again The Internet. I argue the greatest innovation uses all these and is as important as Plumbing – actually our toilets and water supply would not work without it today: I nominate …

The Power Grid

(If this were TV, you would now see this.)

You might say that I am cheating because the power grid is not a singular invention but rather a conglomerate of diverse inventions, held together by the glue of standardization, politics, and committees. I picked the grid for that very reason.

The more I learned about the power grid the more I wondered that it works at all – at that amazing level of availability. In Austria the average downtime per customer is about 45 minutes per year, that is electric power is available 99,99% of the time. Experts state that this even has a negative impact of our ability to cope with sudden blackouts. This is called the paradox of vulnerability: the less vulnerable you are as per statistics, the less you care about very improbably but disastrous events.

At every moment the consumption of electrical energy needs to be balanced with the demand. This sounds trivial but it means that if you turn on your oven, somewhere in your country (actually: in your control area) a gas turbine needs to spin a bit faster. In Austria the gates at a pumped-storage hydropower plant will open a bit more.

If you turn on your computer or other electronic device the compensation needs to be more sophisticated as modern devices distort the nice sine function that alternate current used to be in the old times.

Kölnbreinsperre from Arlhöhe

Storage lake, Malta power plants in Carinthia, southern Austria. Maximum power is 1,3 GW which is more than 10% of Austria’s peak power. (Wikimedia)

If consumption rises faster than demand the frequency of AC power decreases. All generators rotate in sync – most of continental Europe is one large synchronous area. The energy ‘stored’ in rotation is proportional to the square of the frequency. If the energy is not consumed the rotating masses can’t get rid of it. Since the factor of proportionality is the moment of inertia you can compensate for changes in demand by tweaking the generator, e.g. by controlling the flow of water. The grid codes agreed upon by all countries in a control area state that the operators of generators need to respond within seconds.

If something goes badly wrong the synchronous area would split into regions where generators spin with different frequencies – preventing to flow energy between these areas. This had happened in a blackout in 2006 in Europe, which was triggered by a – planned – disconnect of power lines in Germany: allowing for a ship to pass.

UCTE area split at 4 11 2006

Europe’s synchronous area split into three regions in November 2006 (Wikimedia)

What amazes me even more is that the system does still work so well, even after introducing feedback loops governed by a ‘capitalist’ market. I consider the power grid a combination of at least three networks: the network of electrical power, the communications network (stuff for cybersecurity nightmares), and a market of suppliers and customers. We can expect many new types of participants in this market as the producing consumer – the prosumer – and intermediaries aggregating demand and supply.

I am sometimes worried about the consequences of adding more smartness, intelligence and automation for technical and, above all, for commercial reasons. I am not that concerned about hackers changing the frequency of generators, but about perfectly well-controlled computers running mad at the electricity stock exchange (or by some harmless test command wreaking havoc – as described at the bottom of this post.).

In February 2012 is was really cold in middle Europe for about two weeks, and basically all power plants were up and running – not much reserve left for controlling frequency and power. There had been rumors on speculations impacting the stability of the power grid in Germany: Since the stock exchange prices of electricity were high, the balancing group representatives were said to have tweaked their forecasts. As a result the power needed was not standard power to be purchased on a market designed for that but precious energy that should have been dedicated to providing stability. The German regulator explained later that these alleged speculations had not made sense in hindsight but it cannot be ruled out that representatives were tempted to do that beforehand.

The blackout in California in 2003 is often quoted as a textbook example of a software bug affecting infrastructure, as well as the market manipulations causing the Californian ‘electricity crisis’ have been considered an unintended side-effect of market liberalization.

This is all very interesting for the engineering, physics, and IT geek (even including the geek who indulges in applying physics-style differential equations to economics). But the consumer of electrical power in me simply concludes that at all odds you should try to make yourself as self-sufficient as possible.

Advertisement for Windmill Electric Power Generating system 1897

Advertisement for Windmill Electric Power Generating system 1897. “Harper’s New Monthly Magazine” New York (Wikimedia)


For German readers – and actually in order to keep track of that myself – I add some sources only available in German:

Statistics of disruptions by the Austrian regulator, incl. exact definitions for calculating the minutes of disruption quoted in the post.

Malta hydropower plants in Wikipedia.

Stability of the German power grid in February 2012:
Austrian newspaper article – translating to ‘Gambling until Blackout’, a bit sensationalist.
Evaluation by the German regulator, see page 61. They really use the term temptation.

Cyber Security Satire?

I am a science fiction fan. In particular, I am a fan of movies featuring Those Lonesome Nerds who are capable of controlling this planet’s critical infrastructure – from their gloomy basements.

But is it science fiction? In the year Die Hard 4.0 has been released a classified video – showing an electrical generator dying from a cyber attack. Fortunately, “Aurora” was just a test attack against a replica of a power plant.

Now some of you know that the Subversive El(k)ement calls herself a Dilettante Science Blogger on Twitter.

But here is an epic story to be unearthed, and it would take a novelist to do that. I can imagine the long-winded narrative unfolding – of people who cannot use their showers or toilets any more after the blackout. Of sinister hackers sending their evil commands into the command centers of the intricate blood circulation of our society we call The Power Grid. Of course they use smart meters to start their attack.

Unfortunately my feeble attempts of tipping my toes into novel writing have been crashed before I even got started: This novel does exist already – in German. I will inform you if is has been translated – either to a novel or directly into a Hollywood movie script.

As I am probably not capable of writing a serious thriller anyway I would rather go for dark satire.

Douglas Adams did cover so many technologies in The Hitchhiker’s Guide the Galaxy – existing and imagined ones – but he did not elaborate much on intergalactic power transmission. So here is room for satire.

What if our Most Critical Infrastructure would not be attacked by sinister hacker nerds but by our smart systems’ smartness dumbness? (Or their operators’ ?)

To all you silent readers and idea grabbers out there: Don’t underestimate the cyber technology I had built into that mostly harmless blog: I know all of you who are reading this and if you are going to exploit this idea on behalf of me I will time-travel back and forth and ruin your online reputation.

That being said I start crafting the plot:

As Adams probably drew his inspiration from encounters with corporations and bureaucracy when describing the Vogons and InfiniDim enterprises I will extrapolate my cyber security nightmare from an anecdote – one that actually happenend!

Consider a programmer – a geek – trying to test his code. Sorry for the gender stereotype. As a geekess I am allowed to do this. It could be female geek also!

The geek’s code should send messages to other computers in a Windows domain. “Domain” is a technical term, not some geeky reference to Dominion or the like.  He is using net send. Info for Generation Y-ers and other tablet and smartphone freak: This is like social media status message junk lacking images.

But our geek protagonist makes a small mistake: He does not send the test command to his test computer only – but to “EUROPE”. This does nearly refer to the whole continent, actually it addresses all computers in all European subsidiaries of a true Virtual Cyber Empire.

Fortunately modern IT networks are built on nearly AI powered devices called switches which make the cyber attack petering out at the borders of That Large City.

How could we turn this into a story about an attack on the power grid, adding your typical ignorant non-tech sensationalist writer’s cliched ideas:

  1. A humanoid life-form (or flawed android that tests his emotions chip) is tinkering with sort of a Hello World! command – sent to The Whole World literally.
  2. The attack that is just a glitch, an unfortunate concatenation of events, that is been launched in an unrelated part of the cyber space. E.g. by a command displayed on a hacker’s screen in a Youtube video. Or it was launched from the gas grid.
  3. The Command of Death spreads pandemically over the continent, replicating itself more efficiently than cute cat videos on social networks.

I contacted my agent immediately.

Shattering my enthusiasm she told me:

This is not science-fiction – this is simply boring. Something like that happened recently in a small country in the middle of Europe.

According to this country’s news a major power blackout had barely been avoided in May 2013. Engineers needed to control the delicate balance of power supply and demand manually as the power grid’s control system has been flooded with gibberish – data that could not be interpreted.

The alleged originator of these commands was a gas transmission system operator in the neighboring country. This company tested a new control system and tried to poll all of its meters for a status update.  Somehow the command found its way from the gas grid to the European power grid and has been replicated.


Update –  Bonus material – making of: For the first time I felt the need to tell this story twice – in German and in English. This is not a translation, rather different versions in parallel universes. German-speaking readers – this is the German instance of the post.

My Google Searches Might Heat Your Home

Sorry, but this is not about Search Term Poetry!

Rather the contrary: Imagine your search terms could be utilized for something down-to-earth, for something useful.

Google states:

Energy consumption of Google internet searches

Energy consumption of Google internet searches (Google, Feb. 18, 2013)

See more comparisons for Google services here! (Though I am disappointed they did not convert to bath tubs!)

If Google’s computers run in their data centers in the middle of nowhere, this energy will be lost and contribute a bit to more carbon dioxide in the atmosphere.

What if Google would run their – virtual – data centers divided into millions tiny pieces, consisting of computers running in our homes?

This is an idea, that has been presented – though in a more serious and realistic fashion, and not focussed on Google, at the conference Hotcloud 11:

The Data Furnace: Heating Up with Cloud Computing

Cloud computing is hot, literally.

Computers can be placed directly into buildings to provide low latency cloud computing for its offices or residents, and the heat that is generated can be used to heat the building.

Thus in winter or during the night the provider of cloud services would offload / “send” more computing tasks to your heater-computer. Resembling the good old SETI screen saver searching for intelligent life in the universe (which was triggered by your being idle, not by your freezing).

I agree to all the caveats listed in the article, in particular the security related aspects. As a service provider you might not want to place your hardware in an insecure, uncontrolled environment. This is like Smart Meters, just worse. In addition, Google has a point here regarding the efficiency of scale of large data centers.

But it’s geeky nonetheless!

Google, by the way, had once really planned to enter the energy business directly, as MIT Technology Review has reported last year:

[In 2007 Google] posted jobs for engineers who could speed up design of renewable-energy projects and put a team to work improving the heliostat, a mirrored device that focuses the sun’s rays to make thermal energy.

They also ventured into something Smart-Meter-like:

… PowerMeter, another canceled project. The software was meant to help homeowners monitor their energy use. Energy entrepreneur Kurt Brown says it had a major flaw: “Their interface was for nerds. It was something mostly a smart Googler would be intrigued by.”

Probably I would have loved this interface!

And the conclusion is:

The cancelled plans show the hazards of believing that success in computing—where products can take days to prototype—can carry over to energy.

Yes – I got it, but it will not stop me!

Currently Google is a player in the energy business, as an investor in renewable energy technology and owner of  wind farms.

I have come across other speculations how Google might enter the energy business, such as: Google might sell electricity at a competitive price, and users would provide (even more) personal data to compensate for that, or Google might offer their “algorithmic power” to utilities or compete with them with respect to aggregating data. But I cannot trace this down to a real product or service offered by Google today (E.g. on Google’s energy website).

North American users – enlighten me if Google really sells electricity to end users!

Memmingen St Martin Turmstübchen Ofen

Stove (Wikimedia) that does not require nor produce electricity, and that does not search for aliens in its idle time. Makes you 100% autonomous (or only dependent on the coal industry) and neither Google, nor the NSA or your utility can track down what you are doing right now.