Thus, no matter how hard we try, electricity systems will continue to rely mostly on supply side adjustments. Today, this is manageable, because most sources are either providing steady power flows (such as coal, nuclear or run-of-river hydro power plants) or then they are mostly controllable (such as gas fired power plants or hydropower from dammed water pools). With that mix of inputs, electricity on demand becomes possible for most advanced economies. Additions of wind and solar power over the last decade introduced renewable electricity generation technologies into the grid. Those two sources have none of the above qualities: they neither provide steady flows, nor are they controllable. “No wind” means "no power", so does “no sunshine”, and even sharing across long-distances using high voltage DC (HVDC) transmission lines won’t change that fact, due to the stochastic nature of the inputs. Potentially crippling power outages will happen regularly in societies that rely on large percentages of these technologies to meet their electricity demand. With that, the current system of just-in-time electricity delivery would be replaced by one with irregular service interruptions. And yet there are plans made worldwide suggesting that we can produce 20, 30 or 50% of our future electricity consumption from those two sources. This is self-deception at best, and a lie at worst, as it is simply impossible to manage delivery systems where both inputs and outputs are largely uncontrollable, irrespective of other features added.
What is important here: we’re not talking about a future where renewable energies supplement fossil fuel based electricity systems like they do today. Given sufficient backup generation systems powered by fossil fuels, a larger penetration of renewable electricity is definitely possible, and might reduce carbon dioxide production and other externalities, albeit at a horribly high cost. However, these types of add-in systems fail to break our dependence on fossil fuels and don’t prove that we can deliver stable electricity in a world where renewable sources supply a majority of inputs into electricity grids. If that was the objective, we should be honest and just build some wind turbines and match them with gas fired generation capacity for low-wind times, instead of talking about long distance transmission, smart grids, and other technologies that despite their cost don't have the potential to secure the basic objective: stable power at any time.
Someone in the renewable electricity world would probably argue that this is where storage can play an important role. Unfortunately, again, this is more self-deception. Right now, storage that balances renewable sources comes from the flexibility of other stock-based supplies, such as natural gas and hydropower. They can be turned off when the wind blows, and turned on when it stops. The reason why this works is because renewables have such a small market share and often use much larger backup systems. Denmark for example operates its heavily wind-based electricity system with the backing of comparably huge hydro power plants in Norway and Sweden, an approach which unfortunately isn't scalable globally. Not many countries have neighbors with flexible energy generation capacity ten times their own, and that is about what is needed to buffer the huge long-term variability of renewable electricity generation.
Fig 5: Annualized gaps and surpluses from wind (UK simulation)
So let’s for a minute assume that the United Kingdom - one of the world's "best" places to generate electricity from wind - runs on 20% wind power as planned in the least ambitious scenarios currently promoted, and that standby natural gas power plants become no longer available to bridge supply gaps. Some say that ELVs (electric cars) could provide the necessary storage capacity. We did the maths: the total annual output from wind in a 20% scenario for England and Wales would amount to approximately 64 TWh (20% of total current demand). After modeling a nationwide wind turbine network using the best 50 locations (we even included Scotland), we calculated the necessary storage to bridge the largest possible supply gap (e.g. when the wind doesn’t blow for a number of days) and found that Britain in 2009 would have needed 96.5 million battery operated electric cars with 40 kWh batteries each fully available for storage, e.g. no longer ready to be driven. For comparison: 28.5 million private vehicles are currently registered in the UK. The problem here is that wind patterns don't just include short term ups and downs, but instead do involve long periods with very little wind, and then long periods with a lot. Unfortunately, this pattern isn't even predictable year-over-year. Buffering those resources is not something that can be managed with storage, no matter how large. Another fake fireman.
The truth about electricity is simple, surprising and daunting: with the most promising renewable technologies - wind and solar - irrespective of expensive supplements being added, electricity systems as we know them today will not be able to operate. But instead of putting efforts towards finding real solutions, we are spending billions, likely even trillions, of dollars and Euros on technologies that cannot and will not work in the way we expect them to. Again, as a reminder: this is not an argument to defend the way we currently produce electricity, but a strong encouragement to research how we might get reliable power to our ubiquitous sockets without fossil fuels providing the major part. And for those who now suggest to go for a nuclear option: irrespective of any argument about long-term risk, this technology too has a number of downsides, among them the inability to control output according to demand, relatively high cost, and a high dependence on fossil fuels both for the construction of plants and the mining of uranium. And last, but not least, the fact that uranium too, is a non-renewable resources, subject to the fact that we will eventually arrive at the limits of meaningfully extractable material (e.g. the ones offering an attractive RREI) - particularly if we plan on scaling up nuclear power to replace other fuels.
Rispondi quotando
E poi scusa non è vero che importiamo energia da altri paesi? Importiamone un po' meno e facciamo girare un po' più le nostre centrali così da renderle più produttive e quindi più redditizie. Il problema sai qual è. E' che Enel deve aumentare il fatturato anno dopo anno perché questo vuole il mercato. Quindi o aumentano i consumi (e così non è) o si inventano qualcosa per aumentare il prezzo del kwh.
