by Jerome a Paris
Wed Jun 8th, 2011 at 09:35:12 AM EST
| GDF Suez pas enthousiasmé par l'éolien Le PDG de GDF Suez, Gérard Mestrallet, a mis en garde mardi à Montréal contre la séduction excessive qu'exercent sur l'opinion publique les énergies renouvelables, en soulignant notamment le prix élevé de l'éolien.
"Ce sont des énergies intermittentes qui vont nécessiter de grandes capacités de réserve, qui vont reposer sur le gaz naturel en raison de la facilité d'utilisation des turbines à gaz", a-t-il expliqué au Forum économique international des Amériques. | | GDF Suez not enthusiastic about wind power GDF Suez's CEO, Gérard Mestrallet, spoke in Montreal against the excessive enthusiasm by the public for renewable energy, underlining among others the high cost of wind power. "These are intermitten energy sources which will require massive backup, which will be provided by gas-fiored power plants given the flexibility of gas turbines" he stated at the Americas International Economic Forum. |
| Il a illustré son propos par l'exemple d'une île ayant besoin de 1.000 mégawatts pour ses habitants et ses industries. "L'île veut être verte. Donc elle construit 1.000 mégawatts d'éoliennes. C'est très bien, surtout quand il y a du vent, c'est à dire 30% du temps. Mais comme les consommateurs veulent de l'électricité tout le temps, il faut construire à côte de ces éoliennes 1.000 mégawatts de turbines à gaz qu'on peut mettre en route comme des mobylettes quand il n'y a pas de vent et les éteindre quand il y a du vent". "Résultat des courses: on va payer trois fois. D'abord parce qu'il faut construire deux systèmes, 2.000 mégawatts, alors que l'île n'a besoin que de 1.000. Deuxièmement il faudra subventionner les éoliennes et troisièmement, les turbines à gaz vont fonctionner seulement 70% du temps et donc le coût en capital du mégawattheure va être augmenté à due concurrence". "Donc je pense qu'il faut bien réfléchir avant de vouloir s'engager trop massivement dans des productions intermittentes de renouvelables", a conclu Gérard Mestrallet. | | He used an exemple to illustrate his statement: that of an island requiring 1,000 MW for its industrial and residential use. "The island wants to be green, so it builds 1,000 MW of wind power. That's nice, when there is wind, ie 30% of the time. But as consumers want electricity all the time, you need to build alongside these wind turbines another 1,000 MW of gas-fired power plants which can be switched on easily when there is no wind, and off when there is." "The result is that one pays 3 times. First, because we need to build two systems, 2,000 MW, when the island only needs 1,000 MW. Secondly, wind turbines will need to be subsidized, and third, gas turbines will be used only 70% of the time and thus their capital costs will be amortised over less production and their MWh will thus be more expensive. "Thus I think we should be careful before committing too massively to massive intermitten renewable energy," he concluded. |
Okay, let's take these in turn. Follow me below the fold.
He used an exemple to illustrate his statement: that of an island requiring 1,000 MW for its industrial and residential use.
While it's understandable to use a simple system to explain issues, in this case it immediately influences things: the smaller the system, the harder it is to fully run it on renewables. Intermittent production sources can more easily be integrated in a larger system, and the limits to their penetration are farther when you have a complex system than when you have a small, simple system. So, starting with that exemple is already a sign of bias.
"The island wants to be green, so it builds 1,000 MW of wind power. That's nice, when there is wind, ie 30% of the time. But as consumers want electricity all the time, you need to build alongside these wind turbines another 1,000 MW of gas-fired power plants which can be switched on easily when there is no wind, and off when there is."
The second fallacy is to say that the only option that should be considered when discussing renewables is whether then can provide 100% of the electricity. Given that we're starting from almost zero, how about discussing penetrations of 10%, 20%, 40% before worrying about the 100% situation?
The other fallacy here is that full production by renewables is driven by capacity (MW) and not by actual production (MWh). If you want a "green island" you should not go for 1,000 MW of wind, you should go for 5,000 GWh or so of electricity per year, in which case (using the 30% capacity factor Mr Mestrallet uses), you'd work on an assumption of 2,000 MW of wind rather than 1,000 MW and adapt all calculations accordingly.
"The result is that one pays 3 times. First, because we need to build two systems, 2,000 MW, when the island only needs 1,000 MW. Secondly, wind turbines will need to be subsidized, and third, gas turbines will be used only 70% of the time and thus their capital costs will be amortised over less production and their MWh will thus be more expensive.
This is wrong on many levels.
1) As noted above, you'd need 2,000 MW of wind to have a real "system" - in which case, the gas backup only represents an additional 50% of the basics system;
2) then comes the fact that a gas-fired MW costs significantly less than a wind MW - roughly half the price. So the cost of backup, in terms of initial investment, represents only a quarter of the investment in a wind system, which is not quite like building two systems.
3) third comes the unsusbtantiated assertion that wind turbines need to be subsidised. Sources as serious as the IEA or ExxonMobil (hardly natural green-eyed wind supporters) suggest that wind generated MWhs are as cheap as, or cheaper than, gas-fired generated MWh (and that of course takes into account the initially higher cost of the MW). Wind power does not need to be subsidized, it needs long term price predictability to amortise high upfront investments, which is not the same thing!
4) the argument about the cost of gas-fired MWh being increased by relatively low use of the gas-fired plants is disingenuous. In a market system, use of an asset is driven by the marginal cost of production, and the marginal cost of production of gas is typically the highest around (which is why it is the price-making generator), which has as an obvious consequence that gas-fired power plants are very rarely used at full capacity. Data shows that the average capacity factor of gas-fired plants is consistently around 40% in the US and in Germany - so not that much higher than wind turbines. A 70% capacity use, as suggested for Mestrallet Island, would actually be significantly higher than reality and thus make for even cheaper MWhs than what gas-fired power plants provide today...
5) more generally, the exemple does away with the natural complexity of electricity consumption, which is not a flat number: it is higher in the day than at night, in the morning and evening than at midday, and it will have seasonal patterns (which depend on where you are - in the US summer consumption tends to be higher - all that AC - whereas in Europe winter consumption is typically higher). So you'd need to compare the actual output from wind at any time to the actual demand to know how much gas-fired back up is actually needed - and if you have 2,000 MW of wind for a 5,000 GWh/y and 1,000 MW peak system, you probably would not need to start your gas-fired plants that often.
6) of course, these arguments completely ignore that we're not building wind power or other renewable energy sources from scratch, but adding them to a system which already exists, and which already has significant backup capacity (because that's a standard requirements of any electricity system, even a fully gas-fired based one). Reality has proven that a lot more wind can be integrated painlessly into existing systems than has been "predicted" by the skeptics (who, like Mr Mestrallet, have a vested interest in the status quo) - and given the incremental nature of new additions to the system, adjustments to backup, when needed, can be planned and implemented over time as part of the normal 'life' of the system.
7) finally, all this discourse about the pure cost of MW or MWh completely ignores the cost of externalities. Each MWh of wind power means one MWh less coming from the combustion of fossil-fuels and thus less CO2 in the atmosphere. We know we don't have the right tools to assess the value of that, but the sciences overwhelmingly points towards that value being rather high (ie the costs of not getting rid of fossil fuel power plants are potentially massive) and this is ignored because an exact number cannot be provided by the "markets" (or by regulation, which the fossil-fuel burning industries naturally oppose).
"Thus I think we should be careful before committing too massively to massive intermittent renewable energy," he concluded.
It is sad to still hear such ignorant or fear-mongering discourse today.
