“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.

Pumped Heat from the Tunnel

The idea to use a reservoir of water as a heat pump’s heat source is not new. But now and then somebody dares to do it again in a more spectacular way. Provided governmental agencies give you permit, lakes or underground aquifers could be used.

Today a (German) press release about a European research project called Sinfonia caught my attention. The cities of Innsbruck (AT) and Bolzano (IT) plan to reduce energy demands by 40-50% and increase the percentage of renewable energies used for heating and electrical power by 30%. The results should serve as best practices applicable to other cities.

Diverse activities are planned, such as improving insulation, installing solar thermal collectors or photovoltaic panels, and developing ways to renovate even buildings that are subject to monument protection. The latter is quite a challenge in European cities as laws do typically not allow for installing anything that impacts the view of historical rooftops or the structure of facades.

In a smart grid infrastructure, energy demands and supply should be managed, for example by cooling down refrigerators to -30°C if too much electrical energy is available – effectively storing energy in the ice.

My favorite: Heat pumps should utilize water from a very special source – drain water from the tunnel underneath Brenner pass (called tunnel water or mountain water in German).

This source would provide water flowing at 200-300 liters per second at a  temperature of 22°C, resulting in about 10 Megawatt of heating power.

I want to cross-check these numbers:

Assuming low-temperature floor heating loops, heat pumps would need to operate between 22°C ‘input’ temperature and about 40°C ‘output’ temperature.

The maximum theoretical efficiency is limited by principles of thermodynamics: This is Carnot’s Coefficient of Performance, which is:

Thot / (Thot – Tcold)

There are absolute temperatures in Kelvin, so 273 K needs to be added to the temperatures in °C.

Thus the COP is about:

COP = (40 + 273) / (40 + 273 – 22 – 273) = 313 / 18 ~ 17

Carnot’s perfect circular process does not include any phase change – as the evaporation and condensation in a real heat pump – and there are different sources of energy loss.

Thus a real-live heat pump shows a much lower COP. But there is a simple rule of thumb based on experience that is surprisingly accurate: Divide Carnot’s COP by 2 to calculate the realistic COP.

So these heat pumps would operate at a COP of 8,5 which is still very high. The temperature of the tunnel water is expected to be rather constant – as ground water – so COPs will also be high in winter.

Standard ‘geothermal’ brine-water heat pumps show COPs of about 4 – 4,5 when operating between the standard temperatures (values used in standardized tests) of 0°C brine temperature and 35° heating water temperature (B0/W35). As we discussed the meaning of ‘brine’ in the comments recently: In relation to heat pumps this term always refers to a solution of glycol-based frost protection in water.

Water-water heat pumps utilizing ground water with a temperature of about 10°C show a COP of 5,5 to 6 (W10/W35).

I have picked 40° rather than 35° in my estimate, accounting for losses in a district heating system attached to the gigantic heat pumps. Had I calculated with 35° my numbers for the tunnel water heat pumps would even be higher. So the whole exercise is more of an order-of-magnitude check.

The mass flow of about 300 kg (= 300 liters) per second can be converted into power retrieved by the heat pump: by multiplying it with the specific heat of water (4,19 kJ/kg) and with the temperature drop of the water caused by passing the heat pump’s evaporator unit.

The temperature difference in the brine circuit connecting the heat source to the heat pump is about 5 K for standard ‘small’ heat pumps. Water-water heat pumps might also use and additional brine circuit and thus an additional heat exchanger to transfer heat from the source water to the heat pump. I use those 5 K nonetheless as it is not a constant anyway – mentally insert error bars of several 10% here.

The drain water ‘carries’ approximately:

300 kg/s * 4,19 kJ/kgK * 5K ~ 6285 kJ/s = 6285 kW ~ 6,3 MW

The COP represents the factor the electrical energy feed into the heat pump is multiplied with to yield the heating power.

[Heating power] = COP * [Electrical power]

Given a COP of 8 an electrical power of 1 MW would result in 8 MW of heating power, delivered to floor heaters for example. However, the remaining 7 MW then need to be retrieved from the heat source, and the heat source really needs to be able to deliver them:

[Heating power] = [Power retrieved from source] + [Electrical power]

Thus:

[Power to be retrieved from source] = [Heating power] * (COP – 1)/COP

Aiming at 10 MW heating power output using a heat pump with a COP of 8, the drain water would need to deliver:

[Required power from drain water] = 10 MW * 7/8 = 8,8 MW

This is higher than the calculated power of 6,3 MW but the temperature drop I used was just an estimate and 7 K would also as well be OK – let alone all the other assumptions for operating temperatures and COP. So the numbers from the press release are self-consistent.

Brenner basetunnel portalBrenner base tunnel, portal in Austria. The tunnel has been subject to endless political debates and completion seems now to be scheduled for 2025 (Image by Wikimedia user B.Zsolt) I guess the drain water will be available earlier though.

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 has been recorded – 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 wordpress.com 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 his encounters with corporations and bureaucracy when describing the Vogons and InfiniDim enterprises I will extrapolate my cyber security nightmare from an anecdote:

Consider a programmer (a geek. Sorry for the redundant information!) 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. 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.
Circuit Breaker 115 kV

Any pop-sci article related to the power grid need to show-off some infrastructure like that (Circuit Breaker, Wikimedia)

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.