kugelfish

Switzerland has few natural resources besides mountains. In terms of energy this means a significant potential for electricity production from   hydro-power   including about  8.8 TWh   (ca. 15% of annual demand) of seasonal storage in the form of large artificial lakes behind large dams.  Contrary to pumped hydro storage (e.g the  Nant de Drance  or  Linth-Limmern  plants ) which is more typically associated with energy storage, conventional stored hydro power stations in the alps can typically accumulate water in an artificial lake from melting snow and rain during spring and summer and can delay generating electricity to whenever needed, typically in the winter. By extending the previous optimization model , we can see the impact of stored hydropower as a source of flexibility and dispatchable power generation on the cost-optimal system configuration: We are assuming a production cost of 70 Euro / MWh for up to 8.8 TWh per year at a namepl...

 The decarbonization of our energy usage might be one of the most important engineering challenge of our times. Over the last few years, I have been particularly interested in what it would take to build an electric power system primarily on the basis of wind and solar generation and how much it would cost.  Based on reading some papers on the topic and doing some back of the envelope calculations, these is a summary of some observations and conclusions I have come to: The most relevant metric to evaluate the cost efficiency electricity production is the weighted production cost of a combination of technologies which can satisfy a particular load profile at all times. We could call this average system unit production cost or as it has recently been coined in this paper : LCOLC (Levelized Cost of Load Coverage). While the traditional unit production costs (LCOE) can be simply added up, LCOLC requires the use of an LP-solver . For my own calculations, I have mostly assumed a cos...

When it comes to the design of a low-carbon grid on the basis of variable renewable generation plus storage, we have speculated  what on optimal all-inclusive system cost could be , based on today's technology cost. We have also estimated that in an optimal combination,  scaling up wind & solar alone could typically carry about 70% or more of the actual load for most European countries . In many parts of the world, we already see significant investments in wind and solar generation, increasingly complemented by batteries for grid stability and  intra-day arbitrage. However the assumed H2 based long duration storage remains at this time mostly in the domain of research. The reason is that fossil fuel plants powered by natural gas or coal are currently too cheap to be displaced from the role of fully dispatchable flexibility provider of last resort. What would it take to displace fossil fuels entirely from the grid? It is unlikely that low-carbon long-duration sto...

Among advocates of low-carbon energy production there are often competing views on how the power grid of the future should look like. Some countries like France have a strategy that is heavily based on nuclear power to decarbonize the energy system, while other countries like Germany or Switzerland have a strategy that explicitly excludes the construction of new nuclear plants focusing instead on a combination of variable renewable energy sources like wind, water and sun. Both require additional sources of flexible dispatchable power generation to exactly match supply and demand at any time. Assuming we were to build a new low carbon power grid to cover Germany's current electricity consumption, how much would the refusal to include nuclear generation in the mix actually cost? For this augment our p revious simulation/optimization scenario with a fictitious 100% capacity factor baseload generator, operating a different costs to see how the optimal mix would change: For the cost e...

Assuming we could build a power grid that is mostly powered by solar, wind and storage, how much would it cost and how much more would it cost if we did it in deliberately sub-optimal ways? To answer this question, we are using the configuration from a  previous system cost optimization , based on a combination of wind and solar generation, backed by a hybrid storage in order to cover 100% of the hourly load. The hybrid storage consists of Li-ion style batteries for fast and efficient short duration storage combined with inefficient but cheap hydrogen underground storage.  The goal of this new simulation is to see how much the system cost increases if any of the production and/or storage technologies are removed from the optimal mix. As an example, we are using current hourly load and Wind/PV generation forecast for the Germany bidding zone from the  ENTSO-E transparency platform . Then we use a linear program to scale up the current production levels and add storage conf...

I have mostly tried to avoid thinking much or having an opinion about nuclear power. This has been made easy by its minor and stagnating role in the global energy system. But the idea of a nuclear renaissance is now competing for attention and funding in the low carbon energy debate and is becoming harder to ignore. This post is an attempt at sorting my own thoughts on the topic in particular in anticipation of a heated political debate on he future role of nuclear power in Switzerland . Not being an expert in nuclear technology, my opinions are based on the application of general engineering principles and best practices as well as some experience in building high-availability systems. While nuclear reactors might be among the systems that are most obsessively engineered and operated for safety, nothing is ever 100% safe. Whoever promises otherwise is either lying or lacks imagination. There is a general rule in engineering -  that whatever can go wrong will eventually ...

Electricity generation from wind and sun is often criticized as somehow being unreliable. There is even an insult for this in the German political vocabulary: "Flatterstrom!" This is often put in contrast with the presumed reliability and stability of good old baseload power plants like coal or nuclear. These tend to produce largely the same amount  of electricity day in day out - as long as they don't have to be shut down for maintainance or due to adverse weather conditions .  Given that electricity demand is variable, how useful is constant production when the goal is for production to match load at all times? And how much worse would "Flatterstrom" be in comparison? Using again the thought experiment from this previous post , we consider the current hourly load over a year for Europe's two largest electricity markets, France and Germany. Then we assume two generation profiles which in total matches exactly the total yearly:  a fixed, constant production ...