Recently I turned my attention to alternative energy including solar, wind and hydro.

I gave no hydro possibility, but still researched some of the offerings since many of the techniques apply to wind also.

This leaves solar and wind as possible sources of energy.

Solar can be further split into two categories: thermal and photovoltaic.

In this post I will summarize the findings applicable to my own situation.

SOLAR THERMAL

Description: Thermal solar uses energy absorbing black color materials to capture as much of the incident energy from the sun and transfer the resulting heat to a transfer medium to a thermal storage medium.

Benefits:

• Can be a the simplest way to harvest free energy from the sun
• Very easy to understand so DIY folks can and do contribute
• Heating domestic hot water is, perhaps, the easiest energy positive thing one can do

Issues:

• Professional installations have system pricing using a payback period valuation (Return on Investment – ROI) of sometimes up to ten years or more – ridiculous*
• Solar heat, while useful for some applications, is still “low-grade” heat limiting its use to domestic hot water pre-heating (and perhaps full time water heating if well thought out)
• Liquid heat transfer materials may freeze in winter

Summary:
Solar Thermal offers a simple way to offset the costs of heating your water. Fancier systems may offer more energy benefits, but with, I argue, diminishing returns.

SOLAR PHOTOVOLTAIC (PV)

Description: Photovoltaic systems offer a deceivingly simple method of converting radiant solar energy directly to electricity using the light sensitive properties of semi-conductor materials.

Benefits:

• No moving parts
• Long lifetime of components – some claim thirty years
• About as set it and forget it as they come

Issues:

• Generates DC power while household electrical devices use AC power
• Power Inverter required to convert DC to AC
• PV Arrays are more efficient when cold
• Energy payback** may from one to four years or more, but this is getting better as new processes and economies of scale come into play with a growing market
• Financial payback*** is non-existent as PV costs of $4 per watt and up are more expensive than purchasing power from the power company. However, this cost is within one order of magnitude more than energy costs so this parameter is well worth watching.

Summary:
Thus far PV Solar is not an economical solution for consumers with access to conventional sources of power. For the philanthropic or for folks who cannot or do not want to be tied to the grid, PV may be a logical addition to an alternative energy system.

WIND

Description: Wind energy systems absorb kinetic energy from moving air and convert it into a mechanical motion suitable for driving a load. Loads include water well pumps (classic western windmills) and generators for electricity generation.

Benefits:

• Wind is more prevalent than solar in most locations
• Electric Wind Turbines are commercially available, but kits and home-brew components are available for handy folks
• Extensive (and really quite impressive numbers of) DIY groups are all over the Internet providing plenty of real-world examples to follow
• Electric Wind Turbine Generators are available in a variety of power formats including DC, AC single-phase and AC three-phase
• The economics of DIY and some commercial Wind Turbine Systems seems to make good sense

Issues:

• Swinging blades can be noisy unless designed correctly
• Swinging blades can kill you if they strike you
• Many sources of information are woefully ignorant of the aerodynamic realities of turbine blade shapes
• Many sources of information are woefully ignorant about electricity
• Many sources of information don’t seem to know what “Power” really is and constantly talk about the “voltage” they get from their latest wind turbine generator

Summary:
A lot of bizarre information exists in the wind turbine world, but that seems to be a direct result from the sheer popularity of these systems; That is a good sign. The economics seems sound and even without professionally engineered systems, ROI may still be good enough to make Wind Power a practical way to supply my energy needs.

Conclusion:
When I started looking into Alternative Energy Systems I was leaning heavily towards the PV Solar approach. However, I am not in the financial position to displace a 12 cent kWh with a $1 kWh. Thermal solar is also interesting and, if built at home, makes economic sense. Wind Power has one me over as the initial technology to try for my Alternative Energy needs.

Over the next several months, I will be detailing the design steps towards a Wind Power system for my typical Single Family Home to including the following topics…

• Vertical or Horizontal Wind Turbine
• Energy Storage or Grid-Tie
• Two-Blades, three blades, four blades, more
• DC, AC Single-Phase, AC Three-Phase
• 100, 500, 1000 Watts or more
• etc.

This should be fun. Stay tuned.

* A thought about economic nonsense – No economic entity, whether Fortune 500, local small business or a family’s finance, should purchase expensive items with an ROI of more than three years or perhaps five years for very specific types of equipment. Things like buildings are obvious exceptions to this. However, the equipment in the building has shorter lifetimes and hardly ever grows in value like Real Estate. Some PV Solar Systems have lifetimes over twenty even thirty years. That’s great, but you should be the one pocketing the saved energy costs after three years, not the folks who sold you the system. Beware of any vendor that shows you ROI estimates beyond three years. Of course this does not apply to you if you are becoming energy green just because you want to at any price. If that’s you that great and you should be applauded for your generosity. However, most folks have to make good business decisions and ROI three years or less is mandatory.

** Energy Payback – How long system has to operate to recover the energy—and associated generation of pollution and CO2—that went into making the system, in the first place? From www.nrel.gov.

*** Financial Payback – If saving money is your primary goal, then any system must pay for itself within some time frame. As for ROI above, no system should take more than five years to pay for itself with the energy savings to be considered practical. Note if President Obama has his way, energy prices are likely to climb which makes the ROI occur sooner. However, climbing energy prices will also affect the manufacturing costs for the renewable energy products. If you think energy prices are going to climb, investing in your system today makes good sense.