Energy efficiency seems easy, right? You select some energy efficiency technology, you install it, and you save energy. But this is like saying building a house is easy. You hire an architect, you build the house, and you move in. The world doesn’t work like that. There are problems along the way.
Let’s start with the house example. In our county, the county planners will reject your house plans 85% of the time. They may reject them many times, and if you make them mad, you will waste a lot of time and expense. The architect keeps making plans for a house that your grandmother would have liked, but not you. The plumber may not show up on time, and this will back up the dry wallers, painters and everyone else. There are always problems. That is what living is about—solving problems.
In energy efficiency things go wrong all the time too. Your energy audit might have overpredicted energy savings for a certain project. In fact, it may have claimed savings when the new technology actually will increase usage. That happens. I have seen audits that claim more in savings than the client was even using. Often the contractor is low bid, and therefore in a rush, cutting corners, and doesn’t take the time to set up the technology so that it will save energy. Maybe they just are not sophisticated enough. There are a lot of reasons why energy savings does not materialize.
That is why we need Measurement and Verification, or as we call it, M&V. M&V is the process of estimating how much energy and costs were actually saved. Forget what the original engineer projected, what was actually saved?
When we do M&V, we are estimating savings. We can never know what was saved. We don’t know precisely how much energy you would have used. But we can estimate it. We compare this estimate with how much energy you did use, and the difference is savings.