I saw this stupid propaganda on Slashdot:
[Slashdot] Tech Allows Stable Integration of Wind In the Power Grid
One of the most frequently raised arguments against renewable power sources is that they can only supply a low percentage of the total power because their unpredictability can destabilize the grid. Spain seems to have disproved this assertion. In the last three days, the wind power generation records with respect to the total demand were beaten twice (in special conditions: a very windy weekend, at night): 45% on November 5 and almost 54% last night (Google translation; Spanish original). There was no instability. These milestones were accomplished with the help of a control center that processes meteorologic data from the whole country and predicts, with high certainty, the wind and solar power that will be generated, allowing a stable integration of all the renewable power. You can see a graphic of the record here.
First off, by most definitions Spainish wind is only a small percentage of total electricity: 9%.
[IEA] Monthly Electricity Statistics
In 2008, just 27 GWh out of a total of 287 GWh generated were wind/solar/geothermal combined. The only numbers appearing the Slashdot are peak power figures - where for a few hours is wind power five times above annual average. This is what they are pointing to - November 8 2008:
Image credit Red Eléctrica de España
[Red Eléctrica de España] Seguimiento de la demanda de energía eléctrica [requires Flash/SWF player]
(I cut off the axes because I shrunk the image and the text is too small. See the original: the y-axis range is 35 GWe, and the x-axis is a 26-hour time period).
For perspective, compare this to last week - take October 31:
Image credit Red Eléctrica de España
(30-hour time range). Here wind power is down to 1/10th of last night's peak - the figure that actually makes it into the news. And the difference, as you'd naturally expect, is entirely made up of natural gas.
Googling, "resto reg. esp." seems to be co-generation & solar power. The weirdness at the bottom of the graph is a mix of transferring energy via international interconnects (mostly negative), and hydro (occasionally negative when charging pumped storage).
ReplyDeleteInteresting to see that the shortest timescale fluctuations in demand are mostly met by the international interconnects and hydro. So much for their stable smart grid, but hooray for international energy markets.
By eye, hour to hour fluctuations are shared roughly 2:2:1 between combined cycle gas : hydro (including pumped storage) : and the interconnects, while variations over days and weeks are met by combined cycle gas.
Nuclear output looks constant.
Also interesting that spain exports power even when the wind isn't blowing. Are they more economically efficient generators than their neighbours, is it a symptom of having to allow for the variable sources, or just a transitional effect of having invested in transforming their power grid?
Spain is building a new power line to France. This allows excess wind to be exported out of Spain as well as importing more power into Spain when the renewables are deficient. This clearly shows a link between adding renewable generation with its rather fickle output power characteristics and the need for more transmission. To fully convert to wind and solar will require ever more and more amounts of new transmission lines. How many new transmission lines can you stomach or even pay for (California)? And where is England and Hawaii going to build their lines to? They aren't. Thus wind can only play a minor role in England and Hawaii. England recognized this limitaiton and has approved the rapid construction of ten new nucelar plants to address both the global warming issues as well as the problem with importing oil and gasoline for transportation. Thus England now joins France, Korea, Japan, India, and even China in their rapid growth of nuclear programs.
ReplyDeleteEngland already has an interconnect with France, is planning to increase its capacity, build interconnects to Denmark, and maybe Iceland. The new nukes will cover the decommissioning of existing nukes and dirty coal about to reach the end of their lives. We are also (sluggishly) planning to build a lot more wind, as we need a lot more electricity to decarbonise the economy.
ReplyDeleteTransmission over weather-system sized distances, or to neighbours with lots of hydro (Denmark to Norway) makes wind more viable. Doesn't solve the fluctuation problem completely but it definitely helps.
Yeah, talk to the Danes about how great their system works with their interconnect to Norway. Before they used to dump a lot of their wind-generated electricity for free to Norway. But now there's a new rate—negative! So it'll be like garbage, you'll need to pay a tipping fee to dump your excess electricity. Check out this article.
ReplyDeleteThomas, the reason for Spain being a electricity exporter is quite simple. Spain is an energetic island where the external dependence on primary energy is about 80%, but both Portugal and Morocco have even worst numbers and quite limited generation capacity, so we can say that Spain provides energy to their neighbours (except France) by burning additional natural gas bought to Algeria. It could be funny but the truth is that is really sad. I'm a spanish nuclear engineer I know what I say.
ReplyDelete