Wednesday, August 18, 2010

The Key Principle of Energy Efficiency

I have talked to many people about energy efficiency. Almost invariably the discussion turns towards residential solar panels and high performance windows. Now, while these things are important, solar panels are _not_ an efficiency measure but instead an electrical generation system. High performance windows, while they are an efficiency measure, are probably the least cost-effective efficiency measure that one can undertake according to the vast majority of research I've read along with my own personal experience.
To folks at this level of knowledge, I would point out one major tenet of energy efficiency as I see it:

For a grid-connected house, saving energy is the same thing as generating it.

From the point of view of the electrical grid, a house that uses 1 kWh less per day looks exactly the same as a house with a solar panel system that generated 1 kWh that day. Both houses take 1 kWh less from the grid than their unimproved counterparts on any given day, and therefore both houses are reducing their energy bill by the same cost per day, and reducing the environmental impact of generating their required energy by the same amount.
In short, and it is worth repeating, those solar panels or wind turbines on the house are performing the exact same function as any energy efficiency improvements. Because of that fact, if you want to determine whether to improve efficiency or add generation to your home, it is logical to compare:
  1. The up-front cost and effective interest rate of the improvement
  2. The environmental impact of the improvement
  3. The impact on the home's value of the improvement
These should be the major factors to consider when deciding whether to go with a generation option (typically solar these days) or efficiency. Bottom line: don't just assume you have to go with electrical generation to reduce your home's ecological footprint. The same amount of money will likely offset more energy usage if spent on efficiency than if spent on generation, depending on the starting efficiency of your home. If your house is anything like mine was when I started this whole adventure, you have a lot of low-hanging fruit to gather, for surprisingly little money and high rate of return, before it makes sense to consider generation.
That being said, the prices of solar panels have been dramatically reduced and ongoing efforts are being made to reduce installation costs. With appropriate subsidies a solar generation system may make good sense, at least for the homeowner. Whether it is worthwhile in the larger community, when considering the other things that the subsidy money might have been spent on in our current era of budget shortfalls, is perhaps a tougher question to answer.

So is Energy Efficiency Man bashing solar panels? Not in the least. The more the better, particularly in the Texas summer. Here in Austin, we had an all-time record electrical usage number a couple days ago. Solar panels will and do undoubtedly help reduce our peak summertime loads. However, EEMan would like to see every one of those solar panel-covered houses looked at for low-hanging efficiency fruit, so that we can get the maximum reduction in load on the grid. A net-zero (or energy positive) house is a great thing to aim for.

Until next time, be safe and be cool!

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