Questions From Readers – What Amount of Energy is Needed to Manufacture Solar Systems

SolarByTheWatt.com — Mon, 20 Apr 2009 09:05:31 +0000

We will place in postings like this questions from our readers that we can not get enough info on to answer them completely. We are inviting, as in most of our articles, readers with enough access to information and data to comment and point us to the correct sources.

A reader (whose identity we are not going to disclose since they chose to contact us through the Contact Us form) asked whether there we have info on how much energy is used in manufacturing of solar and wind systems, the production of the components and the installation, full cost of maintaining a system like that.

Very interesting question. It refers to the so called net energy balance or net energy result – the difference between energy invested in the creation of an energy source and the useful energy it brings back.

This indeed is an interesting area for research and will definitely get on SolarByTheWatt.Com’s priority list.

The net energy balance is specifically interesting topic with fuels because they are intended to be used once per unit of their quantity – i.e. every pound, gallon, ton, kilogram or whatever unit is used for to measure the quantity of the fuel is only used once to bring useful energy in certain amount (kWh, a galon of gas equivalent of energy, BTU, a barrel of oil worth of energy – whatever unit we use).

It was a very controversial topic when ethanol was becoming popular as a new fuel and there were studies and comments that a gallon of ethanol (or the equivalent of a gallon of gas worth of ethanol) needs more than a gallon of gas to be produced. So though economic efficiency can be achieved, either through temporary market prices differences or subsidies, in reality we can not efficiently convert the raw solar energy stored in biomass (corn, other feedstock for ethanol) in to a usable fuel.

Economic efficiency (see our article on economics of solar) definitely has similarities with the net energy balance issues. A strongly economically efficient technology will definitely have a positive net energy balance since the cost to produce the energy producing facility (fuel or electricity generating plant) will partially cover the cost of used energy and more. If the economic efficiency is close to a net zero, the way it is with solar at the moment where economic efficiency is still achieved only where there are subsidies, cheap capital (low interest loans) and plenty of good insolation, the net energy balance has to be questioned.

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Questions From Readers – What Amount of Energy is Needed to Manufacture Solar Systems