Diverse Renewable Energy Sources Is The Best Option
16 Jan, 2007 11:28 am
Dr. Daniel Kammen is the director of the Renewable and Appropriate Energy Laboratory at the University of California, Berkeley. Answering our questions on future energies, Dr. Kammen introduces us to some types of renewable energy sources and calls for a diverse mix as a solution.
All of these have a lot of opportunity. Solar photovoltaic is one of the most expensive of the renewables, about 25 cents per kilowatt hour. It doesn't have moving parts and can become part of buildings; when it becomes a part of buildings, as we're starting to see in the U.S. and Germany, it can become a real large part of our supply. They work in a simple way; it's just a semi-conductor and a piece of metal that conducts electricity and the sunlight moves the electrons around. We're discovering how to make photovoltaics out of organic materials and plastic. These organic materials can repair themselves, so if they get chipped or damaged, they can actually heal. Wind power is very exciting as well, we could generate very large amounts of energy from wind power; the U.S. could be powered by the wind available in just some Midwestern states. China has a similar situation. Biofuels have all kinds of opportunities, from making ethanol to burning the biofuel directly to run power plants, to gasifying it to make it into a natural gas. Many of these renewables have very large potentials.
Would it be possible for different countries to specialize alternative energies, depending on their respective needs and resources, in order to produce them locally?
Certainly every country has different range of renewable resources they could use. It would be a very unusual circumstance for a country to rely on one renewable resource for power; although it may be very windy, providing an excellent wind source in the Midwest of the U.S., Germany, and western China, you would not want the country to say, ďIím going to become dependent on this energy source,Ē even if itís renewable and good for the environment. You want that diversity b/c the ability for a group to manipulate prices is not a question of fossil fuel resources, but a function of market power. What you want, ideally, is a good mix. Fortunately, the availability of renewable fuel sources tend to be available in different amounts, thereís a good mix of all of them.
Geothermal energy holds great potential as an energy source. What are some methods through which we harness it? Why isnít it being implemented on a wider scale?
I donít think itís that great of a resource. In some locations, it can do quite well; in California, they get 5% of their energy from geothermal power and New Zealand gets well over 50%. But these are locations where you are near hot lava underground. The deep-drilling sort, the geothermal that everyone has, is the kind you need to drill several miles underground to access it, where you essentially have a pipe that goes down to a hot rock. That is not an energy source from which you can produce easy, large amounts of energy from. Itís not likely to become a dominant source unless the technology for extracting heat from underground becomes very very efficient. Itís very likely to be one among the mix, but not a dominant one. The ones that have shown so far, to be a large part of the mixes is solar, wind, biofuels, and the one that Ďs just emerging now, and may become a significant power, but of which we donít know yet, is tidal and wave power.
Can we store solar energy?
We can store it now, certainly. We can store it in batteries, we can store it by pumping water uphill in places like California and Norway, who have networks of pumped hydro. The issue is except for pumped storage of water, itís expensive. The cost of the storage mechanisms, whether itís batteries, fly wheels, or ultra capacitors, the prices need to come down. In fact, they need to come down quite a bit. When you have a choice between producing a lot of energy and storing it, if itís storage isnít quite inexpensive, itís better to have the ability to generate more. Whether itís generating more with renewables; for example, California has a very good wind source, but itís on primarily at night. Storage needs to come down. When the price of batteries comes down, a lot of interesting opportunities open up. We could run our vehicles the reverse of how we do it now; our vehicles could run primarily off of a plug-in battery source and whatís in your liquid gas tank acts a reserve, whether itís ethanol or gasoline. This next generation of plug-in hybrids are being talked about very seriously. There are plans to introduce large numbers of them to certain places, but that would depend on battery prices coming down considerably.
What is your opinion on the international ITER program, whose goal is to show that energy production using atomic fusion is scientifically possible on fusion power?
The ITER project is very important. Itís a real shame that the U.S. has dropped outónot because the other countries wonít do a good job, but because one would like all the major countries to be players in it. The ITER project really has the potential to move fusion along. Weíve been under-investing in fusion for too long. If we properly invest in fusion, we will no longer have this joke that fusion is 50 years away from being commercially ready and it has been like this for 50 years. This is only true because we have been under-investing for 50 years.
How available are these alternative energy sources to developing and/or poor nations?
Some of these countries are way ahead of us. A lot of these countries are only building their national grid systems now, because they have a chance to do it right; they have less invested in the old way of doing things. In East Africa and in Kenya, more people get their electricity from solar as new customers each year. More people, as a percentage of the population, get their energy from solar than any country on Earth. There are places like that, like inner Mongolia, where more than half of the rural population gets its power from wind. Renewables are actually ahead of where they are in developed countries by quite a bit. The issue is there is an overall lack of power in these countries, so you need to build up the overall supply, but biofuels are available around the world. In fact, many poorer countries have better solar and wind resources than others do.
In your opinion, how long will developed nations take to make this transition to future energies?
Developed nations are moving too slowly. But I will say, a few leaders are doing it now: Germany and Japan have become remarkable leaders in this. California, acting as its own country, is doing a significant job in changing things. Spain is becoming a big leader in wind power. Even though things are moving slowly, they are moving. The real important thing is that we have the ability to build up from this.
Interview by: Thanh-Tam Candice Vu