Monday, April 09, 2007

Solar Heat and Wind Power-Eliminating Energy Cost Increases and Green House Gas worries

I've said previously that solar heat and wind power technologies are the most viable alternative energy sources. These twin sources, working together, are ideally positioned to resolve many of today's worries. Pairing of these two is key, because energy demands can largely be divided into two spheres, heat/cooling and work/power. And solar heat is ideal for the former, wind energy for the ladder. For more on understanding the significant differences in the two types of energy, see my previous article explaining why electricity is inefficient in direct heat applications.

So, let's explore why I believe these two sources can eliminate future energy cost increases, and at the same time, eliminate today's worries about the Green House Gas (GHG) link to global warming(see previous article and associated comments on global warming for debate on this connection). First, the similarities... both are plentiful. Just a few hundred square miles of the earth's surface dedicated to each source can meet all the earth's energy needs for the foreseeable future. And, both are viable at today's energy prices.

But there are significant differences between the two, which explain why both are necessary for the practical solution. Both are variable, but they vary based on different, largely non-correlated cycles. Solar heat has regular night and day cycles. Wind varies based on fronts, high and low pressures. But, most of all, solar is ideal for heating and cooling applications. Wind is ideal for power/work applications. By looking more deeply into each source, I hope we can understand the future viability of each and how the synergies between the two mean they can virtually eliminate any worries about increasing energy costs and GHG related global warming.

Wind energy translates easily into the higher form of energy, the work/power sphere, usually in the form of electricity. Efficiencies can theoretically be over 50%. And costs are relatively low. The cost of generating electricity with wind power has come down approximately 85% since the 70's, when the last surge in wind generated electricity took place. It is competitive with conventional sources today, and in fact, has been marketed at rates lower than many conventional utilities in some areas within the past year or two. And, it has the potential for further improvements in cost. Venture capital firms are plowing funds into wind energy in levels never before seen.

Wind efficency improvements have been largely a function of scale and turbine efficiency to date, but I believe the biggest improvement is yet to come in the form of increasing altitudes. This potential is the result of two well known facts. One, wind speeds increase as a function of the height to the 0.15 power. And two, power increases as a function of wind speed cubed, or to the 3rd power. All this means that the wind energy available increases dramatically as height is increased. As an example, the power available at a height of 1500 feet is over 5 times that at 33 feet, the standard wind speed measuring location. For this reason, it is an axiom of wind energy that it makes sense to put your money into raising the turbine rather than increasing the size of the turbine. But, as we have learned in the offshore oil and gas field, fixed structures quickly become self limited in deeper water and the next level is flexible, or moored structures. I believe that the same revolution will take place in wind energy. Turbines will get away from fixed structures and will be moored, perhaps with a kite-like arrangement. This will allow significant increases in height of turbines at much reduced cost, leading to substantial increases in economic viability.

As I mentioned, wind energy is ideally suited to electricity generation. That means running such things as lighting and small motors. It also means potential to drive vehicles with either battery storage or by generation of hydrogen. If the widely expected hydrogen economy is to develop, it must have a source of hydrogen, which electricity can provide via electrolysis.

But, let's shift to solar heat, as distinct from more widely recognized solar electric panels. Solar electric panels are relatively expensive, and deliver efficiencies between 10-20%. Worse, storage of electricity is relatively difficult. Solar heat, on the other hand, can have efficiencies for heating applications well above 60%. Further, the materials of construction are relatively common. And, small scale heat storage is relatively easy with thermal mass using common materials such as water, concrete, rock or earth. And, I as described in my previous article on cooling with solar heat, translating heat to cooling is relatively easy and efficient as well. I am convinced that these technologies also are competitive with current sources, although I'm a bit baffled that I don't see the venture capital flows I would expect in this area. Perhaps the reason is that solar heat is more suitable to small, distributed applications rather than large commercial applications. If that is the case, it may offer each of us an opportunity for some lucrative venture capital application around our house. And for entreprenuer, the opportunity for developing and selling small scale systems.

The good news is that most energy applications can be efficiently satisfied by one of the two methods, and both essentially eliminate GHG from the equation. It is possible to cross over between the two, ie create heat and cooling with electricity or work/power/electricity with heat, but efficiencies for each would be lower. But, this crossover could help manage the variability in each source and peaks in the demand from each sphere.

So there you have it, the potential to solve two of the earth's most pressing worries. And, all with mininal damage to our current way of life. In fact, you could argue that these technologies could increase our prosperity, in contrast to the calls for sacrifice which usually dominate the approach to these two areas.

1 comment:

Universal Solar said...

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