As it happens renewables are actually less variable than nuclear or coal over the short term. The UK National Grid has done a lot of work in this area and concluded that renewables are more reliable. The simple fact is that if the wind is blowing at 20 km/h now it will only vary by 1-2 km/h over the next 15 minutes. If a turbine fails you lose a few megawatts. If a cloud passes over your solar PV output only drops slightly, unless it is a large cloud front which is also easily predictable. Compare that to say nuclear where if a turbine goes down you like lose 500MW or more instantly and without any warning, meaning you need much more spare capacity on-line all the time.
The controller itself has a published price of about a dollar. So maybe it's $.50 in volume. Add a $.50 MOSFET and do that for each of the 36+ cells on a typical panel and you have one very expensive solar panel. I'm still betting that the bypass diodes are done on a string basis of approximately 15-18 cells per "diode" - ideal or actual.
Dave, any reference for the claim that 50% of Germany's electricity supply comes from solar?
There are loads of references for the fact that 50.6% of Germany's electricity supply came from solar during a one hour period on the 9th of June this year. It was an exceptional figure, since it was a very sunny day and a national holiday, with unusually low demand.
Journalists being journalists, there are plenty of headlines with more extravagant claims, and I guess Dave may have seen one of these.
In the first quarter of 2014, renewable energy sources met a record 27 percent of the country’s electricity demand, thanks to additional installations and favorable weather. “Renewable generators produced 40.2 billion kilowatt-hours of electricity, up from 35.7 billion kilowatt-hours in the same period last year,” Bloomberg reported. Much of the country’s renewable energy growth has occurred in the past decade and, as a point of comparison, Germany’s 27 percent is double the approximately 13 percent of U.S. electricity supply powered by renewables as of November 2013.
Germany is looking to reduce CO2 output by 40% by the mid 2020s. They are on target for that, reducing the number of coal plants and replacing old ones with new cleaner ones.
What are currently termed clean coal and clean coal boilers put out slightly more CO2 than other coal systems. They are considered clean because they only produce CO2 instead of a nasty cocktail of things.
They are using carbon capture for the CO2, and eventually even those plants will be run down. As it is they don't think that the new ones will ever make any money. I think they will probably be nationalized at some point, or at least the operators will go from making a profit on the output to being paid to keep them running as backup for renewables that supply the majority of energy. Public ownership of the grid has already begun to happen.
Do you have any information on that? I thought there had only been pilot projects for CO2 sequestration, either abandoned before completion or after some experimental operation. I've been Googling and I can still only find one abandoned German project.
http://en.wikipedia.org/wiki/Carbon_capture_and_storage#Example_CCS_projects
It's a multi-billion dollar industry.
This is a coal power station that currently emits zero CO2.
http://www.eskom.co.za/Whatweredoing/ElectricityGeneration/PowerStations/Pages/Majuba_Power_Station.aspx
The news headline..
http://www.timeslive.co.za/local/2014/11/06/majuba-power-station-increases-capacity-eskom?PageSpeed=noscript
A loss of 10% of a nation's generation capacity due to a single fault is pretty lousy design.Which is why they need distributed renewables.
A loss of 10% of a nation's generation capacity due to a single fault is pretty lousy design.
Which is why they need distributed renewables.
Renewables actually work quite well off grid when you know their limitations and there really is no other viable alternative. For the rest of mankind, living in the developed world they are a solution espoused by the vocal blinkered few that IMHO will end up with the economies of entire countries and continents collapsing in their desire 'to save the planet' That governments have forced consumers in many countries to subsidise their deployment is IMHO obscene.
After reading through this thread and seeing how many people have misunderstood Dave's point. Here's another way of putting it. In economics one of the most rudimentary things to understand is opportunity cost. Opportunity cost is the reasoning Dave is using here. For example, lets say that you start an engineering contracting company and you're able to take home a salary of $50,000. Anyone in their right mind would say that this business is viable and that you are successful. But say that if you were to not have that business you would work for an established company as an engineer and be able to make $70,000. It no longer makes any economical sense to keep your business as your opportunity cost of owning that business is $70,000 giving you a profit of -$20,000. The opportunity cost of running that business is your next best source of income which is in this case GREATER than what you're currently making leaving you with a negative profit. To apply this to solar roadways, it does not matter how efficient solar panels get or if a solar roadway is able to make a positive profit, the opportunity cost of building these solar roadways will always be huge as these panels could generate 5x the output in their intended orientation. Even if a solar road is able to make a $500 profit each year, it's opportunity cost will be $2500 which gives us a NEGATIVE profit of $2000 when using solar panels as a road. Now say a new solar panel comes out that can make $1000 a year as a road, great! But you could still be making $5000 using these in their most efficient orientation. The opportunity cost of using them as roads is $4000.
Thanks for the videos and math Dave. Keep 'em coming
Some on-grid renewables make excellent sense, because they have natural compatibility with people's needs. For example in Texas there is considerable wind. It is predominantly a nightime event, and that's when people's cars are available for charging. So, if a culture of electric cars can be developed, and those cars support rapid load shedding commands, you could have a pretty good renewable energy scheme. Of course, there will be times when customers are becalmed long enough to feel like the tall ship crews of old, but at least there is a natural cure for the short term storage problem, because the loads have appropriate flexibility.
Some on-grid renewables make excellent sense, because they have natural compatibility with people's needs. For example in Texas there is considerable wind. It is predominantly a nightime event, and that's when people's cars are available for charging. So, if a culture of electric cars can be developed, and those cars support rapid load shedding commands, you could have a pretty good renewable energy scheme. Of course, there will be times when customers are becalmed long enough to feel like the tall ship crews of old, but at least there is a natural cure for the short term storage problem, because the loads have appropriate flexibility.
So it's windy at night, but it's not windy every night, nor all the year round. For the nights when it isn't windy all these vehicles become immovable objects next day, or you have to run 'conventional' generation to charge the batteries, or watch your economy collapse when people can't go to work. Lets just plug some figures in. Car population in the USA is roughly 0.8 per capita, or for 26 million persons in Texas around 20 million vehicles. Assume 25% market penetration of electric vehicles of a similar type to the current Tesla S, whose batteries are 85kWh giving a storage potential of 425GWh, a big number, sounds impressive, but what happens when the wind doesn't blow, assume 15% top charge up required every day, and an 8 hour 'slow' charge. Roughly 9GW of generation is required.
Cost of 9GW of generation sits around doing nothing on the off chance the wind doesn't blow, or blows too hard, around 9 billion dollars (for CCGT Gas) and that is just the capital cost, not the fuel. 500 million dollars in interest payments alone at around 5% the shareholders will demand.
Wind turbines meanwhile operate at a real world capacity factor of around 20%, so to meet that 9GW demand it requires 45GW of wind turbine capacity. Cost of that is around 1.6 million dollars per MW capacity (3MW turbine Vestas / Siemens or 4.8 million dollars per turbine) 45GW requires 15000 wind turbines or 72 billion dollars, 3.6 billion dollars in interest payments alone at 5%
A total of 81 billion dollars capital invetsment required to support a population of 5 million vehicles. 16000 dollars per vehicle.
Lots of figures, all roughly in the right ballpark but one thing that keeps cropping up time and time again. Why pay for two sources of energy when just one will do. Mines a nuke. Sits there for months on end just doing the job round the clock. Lasts half a century or more, the entire 'waste' of a 1GW station fits in less space than an olympic swimming pool or can be recycled many times (although digging for new ore and processing it is cheaper) Meanwhile the horizon is unspoilt, there is no noise, the lights stay on.
Grid connected wind turbines are truly horrible things, IMHO only ever fit for the bin.
I think that in general wind power is a stupid idea, unless you come up with some seriously effective storage scheme, which can get you over really long periods of low energy input to the system, and can smooth out the short term highs and lows.
That's a really bizarre argument. Here is a load of clean energy, you just need to make some up-front investment to harvest it and get a massive pay-off. But nah, let's ignore it because it isn't quite as easy as building another coal plant, or because it won't help the power company get richer fast enough.
A more sensible argument would be that we need to improve the grid and our stand-by sources to take advantage of this, and keep building more storage.
After reading through this thread and seeing how many people have misunderstood Dave's point. Here's another way of putting it. In economics one of the most rudimentary things to understand is opportunity cost. Opportunity cost is the reasoning Dave is using here. .......
Germany is looking to reduce CO2 output by 40% by the mid 2020s. They are on target for that, reducing the number of coal plants and replacing old ones with new cleaner ones.
Pray, tell us how? If you can really crack the storage problem its pretty straightforward to move to 100% renewable energy.
Pray, tell us how? If you can really crack the storage problem its pretty straightforward to move to 100% renewable energy.
Oh, I see your mistake now. You are assuming 100% renewables is the only option. Most people expect there to be a mixture for the foreseeable future.
Pray, tell us how? If you can really crack the storage problem its pretty straightforward to move to 100% renewable energy.
Last I looked into it, this mob had a pretty compelling and well researched plan:
http://bze.org.au/
Now you are being a troll.Sorry, in future I'll try only to say things that you agree with and avoid poking holes in your arguments.
They seem to be proposing a mixture of fossil fuels with carbon sequestering, and molten salt storage to even out the renewables. The success record to date with both those is not exactly inspiring.
Neither is the success record of coal or nuclear... Fortunately we don't just give up when there are engineering challenges.
That's one of the biggest mistakes that brownies make. They expect everything to work perfectly first time and be a drop-in replacement for existing dirty energy sources. They seem to forget that it took time and money to perfect other energy sources, and would rather just keep polluting and making other people pay the real costs than actually try to improve the environment they share.
After reading through this thread and seeing how many people have misunderstood Dave's point. Here's another way of putting it. In economics one of the most rudimentary things to understand is opportunity cost. Opportunity cost is the reasoning Dave is using here.
*snip*If that is what Dave really meant than all right, true and true.
But the problem was that he deliberately went out of the way to explain that the whole concept is to put solar panels to the most hostile environment possible and because of that it will never be sustainable.