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Sun Volt

Sun Volt Solar

earth, the final frontier

Clean Energy, Clean Environment

We are at a cross roads in human history, we can choose to continue on as we have been, or we can make a change to improve our future and quite possibly the future for several generations to come. We are here to promote energy independence, a better environment, a secure future and a higher return on investment for your hard earned dollar. It is what I believe in, it is why I am in the solar business.

Energy Storage

17 Feb 10 | General

One of the main problems with solar power is that of storing energy for non-solar periods.  On any given point on earth, there are an average of 12 hours of sunlight per day over the course of a year.  Unfortunately, it is the times when the sun is not shining that we need it’s power the most.

With grid connected systems, during sunny periods, excess power is dumped into the grid, for a credit to be used later.  The problem with this approach is first, the grid has to be present.  If the electric utility is out, then no power is being generated by the solar array.  In most parts of the US, at least right now, this happens only occasionally, so it is not a big concern.  The second consideration is with fossil fuel based grid generation, there is something called the spinning reserve.  That is to say, a generator running at one half it’s rated capacity has the other half in reserve.  With any fossil fuel based generator, as the output from the generator drops, the efficiency drops as well.  Therefore, saving 1 kWh of electricity does not automatically correspond to a 3,412 BTU reduction in fuel input (or 5,732 BTU if considering 32% grid efficiency).  It would be some fraction of that, which is one of the reasons why renewable energy is such an up hill battle.

The real answer is better batteries.  The lead acid battery technology we are currently using has not been improved in over 100 years.  There have been some strides with things like laptop batteries and cell phone batteries, but those are relatively small.  The main issue is power density, e.g. very heavy large batteries storing not enough electrons.  In order for renewable energy to really be meaningful, better energy storage needs to be developed.  This would also help out things like plug in electric vehicles (PEV).

Lawrence Berkeley National Laboratory is on it.  They are working on batteries for vehicles, but by extension, that technology could be applied to renewable energy as well.  This is one of the critical steps in solar development.  You can keep up on developments by following Venkat Srinivasan’s blog, This week in Batteries. He explains things much better than I ever could.

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17 Feb 10 | General | Comments (0)

Capture and store the energy from Lightning?

21 Mar 09 | Technology

A few years ago, I was having a conversation with my brother in law about wind mills and solar panels and he stated “Why can’t we just use the electricity in lightning?”  To which my answer was of course, there is no way to safely do that.  Then I thought about it.  Lightning has a large EMP (ElectroMagnetic Pulse) component that travels some distance away from the actual lightning strike.  In fact, most equipment damage cause by lightning is due to induced currents on power and telephone transmission lines, not direct strikes.

What if say, around tall metal structures like radio and TV transmitting towers, arrays of EMP capturing devices connected to banks of large capacitors were employed.  During a lightning strike the capacitors would become charged, then they could slowly discharge there stored energy to the electrical grid using grid tied inverters.  Of course, this would work best in an area where there is a lot of lightning to begin with, like Florida, for example.

The average lightning strike disipates about 1 Terawatt of power in about 20-40 microseconds.  The magnetic field generated from this event travels out uniformly from the strike point disipating exponentially as a function of distance.  Therefore, the closer to the stike point, the higher the field and the greater yield potential.  To store any meaningful amount of power, a massive capacitor bank, or capacitor bank and battery bank connected in parallel would be needed.

Perhaps some further research is in order.

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21 Mar 09 | Technology | Comments (0)