"I only know that I know nothing", Socrates.
This week I am exploring questions that I have about greentech. Some questions may have a simple answer and some may be just rhetorical questions. Perhaps by next week you (the reader) will provide some answers and shine some light into this darkness. So here it is:
When I heard the debate last week, as well as in previous debates, the subject about alternative energy was present. Both candidates agree that new sources of energy are needed (I don't want to start a political discussion, so let's focus on the big picture) with some differences here and there. Both candidates talk about Nuclear power, but NEITHER CANDIDATE ADDRESSES THE DANGERS of this kind of energy source.
It is my understanding that the biggest problem with Nuclear power is the use and disposal of the radioactive fuel. I have heard (and here is my first question) that nuclear plants use less than 5% of the radioactive material power, is this true? And then, we are left with highly dangerous waste that takes over 10,000 years to become safe? To make things more complicated I have also heard that if we increase the percentage of world power generated by nuclear plants we will have no space left to safely store this radioactive material, could this be?
Why is Belgium, a country that generates 54% of its electricity through Nuclear plants, trying to stop construction of new plants and setting additional tax to existing nuclear power generation. Belgium, as well as Germany, the Netherlands and Sweden have all pledged to phase out existing plants. Why?
I would very much like to know the answers to these questions before we embark on a journey that may lead us into a global disaster!
Let's forget about Nuclear power for a second, let’s focus on a wider subject. How are we going to find a way to generate energy without draining the resources that we have in Planet Earth and without polluting our environment?
I guess most of us agree that the current way we generate energy and dispose our waste is dangerous for our future (please note I said: "most of us". "Why is this so?" is a question I will not ask here, for now).
In order to search for an answer on energy efficiency we need to look at the laws of thermodynamics. The first law states that "Energy can neither be created nor destroyed. It can only change forms". Therefore, we will be better off if we try to use energy that comes from outside our planet: Solar energy. Right?
Well Solar energy is the direct consequence of the power of the sun that enters the earth. But waves, wind and tides (I'm not sure about geothermal) are also partly or wholly a consequence of the sun's effect. So, if we choose wind over solar power, are we selecting an indirect source of power and therefore sacrificing efficiency?
In evaluating an energy source we need to look at two factors: (1) how much energy can we "capture"? And (2) How much energy are we going to waste in the conversion process to its "final destination". And finally compare these numbers to the associated costs in order to find the best solution.
(1) Energy "capture": Solar energy is hard to capture, current solar cells can only attain around 8% efficiency. Other cells are able to convert up to over 40% of the sun’s power, but the cost of the materials used in such cells is prohibitive. Never mind that solar cells depend on the exposure to the sun and therefore are useless at night or with minimum light conditions. Why can’t we have both efficiency and low cost? Is 40% the best we can do?
Wind power has a theoretical limit of 59%. This means that the best wind and the best turbine in the world can only obtain 59% of the energy contained in wind (which already is a factor of the energy coming from the sun!). Can we have wind as our main source of energy with a ceiling of 59% efficiency?
(2) Conversion process: It's not enough that solar cells are inefficient within themselves, the process to convert direct current (DC) obtained with the cells into alternative current (AC) requires inverters which eat up between 5 and 50% of the electricity generated. Wind has a similar problem; the rotation generated by the wind has to be converted into a faster rotation speed to match the frequency on the electricity in the grid. This conversion lowers the efficiency of the turbine. Can we find a system that minimizes the loss of power in the conversion process?
Cost: No alternative energy source up to date has an associated cost that can compete with fossil fuels. Right? These sources depend on government subsidies; the idea is to promote economies of scale until they become competitive. Is there ever going to come a day when alternative, sustainable energy is less expensive than coal?
Wind and sun are variable sources; storage needs to be added to the system to make it work. Supposedly one of the most efficient ways to store energy is by pumping water into a high level storage, and later using the water's falling energy to regain the stored energy (this system achieves about 75% efficiency). Can we use such a system in a large scale alternative power generator?
As for Wave and Tide power generation technologies we have yet a long way to go, those areas are far behind wind and solar. Are we doomed to use fossil fuels until they run out?
In the alternative fuel vehicle arena, the argument of many proponents includes the following statement: "We use less than 25% of the gas in the car to generate forward motion" (the rest of the fuel is spent on noise, electric gadgets, pollution, etc). Can this be?
If the efficiency of current vehicles is so low, how come we have not been able to create a more efficient car in a shorter timeframe?
Finally (I am running out of space), I have trouble understanding the logic behind Hydrogen. Why are some people proposing hydrogen as a fuel? Supposedly hydrogen is a great storage media for electricity. The simplified principle is as follows: add electricity to water and you get hydrogen; turn the system around and release the electricity and obtain water back. Well, using the second law of thermodynamics the amount of electricity released from the hydrogen can only be the as much as the electricity injected in the water. This is power storage not fuel!?
I know that many of you will disagree with some of the ideas explained above, please give me your point of view! I also know that some concepts are explained superfluously, unfortunately I have limited time for this blog, and if I get enough requests I may write a book in the future (just kidding!).
Before leaving, I have to announce this week’s big news: I am father of a baby girl, Dana! (my third child).
Until next week: SHALOM!
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3 comments:
Hey,
I find yr Note very interesting.
Here is my comment -
All resources for the alternative energy should be commercially viable + socially acceptable.
The clean & one of the best alternative is Vegetable ( non-edible ) Oil as the source for Bio Diesel to generate Electricity & Fuel.
Jatropha and Pongamia are two such non edible Veg. that can grow on " semi-Waste Land " with minimum water consumption.
This does not effect the " food crop " and can be most competitive in price. ( unlike Corn, Olive, Palm & Sugarcane )
Countries like Brazil & India have been growing these for centuries but only the recent research has discovered it as the rich source of Oil > Fuel.
( SVO - Straight Vegetable Oil ) )
The plantation brings about more Green Cover, increase the Rain Table, Generate employment for rural communities, etc.
I promoted the Energy Company in India with Plantation of Jatropha with Pilot Project of Bio Diesel.
I will be happy to share more on my experience, should you / anyone like to know.
Cheers
Umesh Dhagat
Chairman
BioDzl Energy Farms Pvt.Ltd.
www.biodzlenergy.com
Umesh:
Interesting comment and interesting company. Thanks for sharing!
Sami Shiro
* Energy will be one of the key global hot buttons over the next 50 years. The U.S. has not been particularly good at putting together a comprehensive energy policy, let alone an alternative energy policy. The last real attempt was undertaken by Carter, whose administration touched on curbing demand, energy efficiency, diversification of the energy matrix (including nuclear and renewables), and QFs, which sowed the seeds for effective power sector deregulation, implemented first in Chile in the early 80s. Since that time nuclear has fallen into disfavor, due to some near accidents and inefficient early plant capacity, and is now back in favor. Even more efficient mini-nuclear technologies like PBR are being explored. For a better treatment of the subject look to France, Sweden, and Japan for case studies. Germany is trying to denuke, but let's wait and see what happens with Russian natural gas first. Obviously there are serious complications with nuclear energy that extend beyond radioactive half-lives, particularly today. But, because investment decisions have to be over long periods of time and you can't just let the back-end of the economy drop out, it shouldn't be a surprise that nuclear energy is on the radar and does have a place in energy matrices.
* Solar energy is often considered the silver bullet, but when and in what form? Actually, who cares about the form as long as it results in a net positive. The question is how to measure that. You can look at returns on investment and fully loaded costs of energy from cradle to grave. Solar PV, e.g., does not stack up so well today, and is heavily reliant on subsidies. Wind power can compete with marginal fossil fuel capacity in some energy matrices on an unsubsidized basis... but not so easily in the U.S. where wholesale power costs are quite low. Of course, you could argue that these wholesale costs currently understate the true cost of power. But who is going to effectively measure that true cost and revamp regulatory frameworks to take it into account? Now we have states squaring off against the Federal Government, which has rolled over on the issue completely under Bush rather than crafting a realistic, long term plan. It's funny seeing the Europeans implementing a traditionally American idea with the ETS, despite its flaws. Don't get me wrong, when it comes to energy issues, none of the relevant political parties in the U.S. has much chest-pounding to do. That's the problem with energy... it's too political.
* Solar is one alternative to ramp up in the energy matrix, whether it comes in the form of PV, heat, wind, or photosynthesis. Biofuels is an interesting use of solar to consider, despite some of the high profile, and often erroneus, food vs. fuel arguments popularized in the press. If we consider the consumption of gasoline, you realize that the process of extracting and bringing the gasoline to market consumes enough energy itself that you end up with only 85%-90% of the fuel's initial calorific value (in the form of crude oil). On the other hand, if you consider the biocarbon cycle that produces the same volume of ethanol from sugarcane or biodiesel from certain oilseeds, you realize that the process generates 8x + the energy than what was put into it. Now that's a relatively impressive use of solar and bang for your buck. Of course that does not work with every crop and you will have constraints related to the availability of water and arable land. But, clearly, there is still potential there to be exploited. When you consider that engines are < 25% as efficient as you pointed out, it's nice to have a process that gives you a net energy efficiency gain on energy before its consumption. Burning biomass in a boiler probably also shows some interesting potential, and there is significant technology upside in this space... technology that takes us beyond food crops.
* If wells-to-wheels efficiencies are < 25% and power grid efficiencies from fuel to socket are ~30%, energy efficiency should be a huge area of focus. Policy may be required to kick-start its implementation. For a curious story, look at what the EU is doing to the import of cheap energy efficient bulbs from China. It's no small wonder consumers are not rushing out to buy their bulbs.
* H2 is often referred to as an energy carrier as opposed to a fuel, and it came come from other sources other than electrolysis. The problem with H2 is that it likes to bind to everything. Separating it, storing it, compressing it, and transporting are considerable technical challenges. An H2 economy started sounding appealing because fuel cells, the passive electrochemical agents of the economy, have significantly higher energy conversion efficiencies than do traditional power generators or engines. Of course, as you have pointed out, if you lose energy content of the fuel, net-net, H2 can be a losing proposition. But, there are places where H2 can make sense, and there are high efficiency fuel sells that don't need to run on pure H2. How important these will every become in the future global energy matrix is a big question mark. What we do know is that any sort of mass production would be a long way off as evidenced by the drop in BLDP's market cap from the heady days of $14Bn to < $200Mn today. At least the H2 discussion has generated interest in upgrading existing battery and other storage technologies, which will be critical to our energy future.
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