Renewables? Reduce Demand First

Learn to drive to before you get the Porsche

One of the premiere driving machines available is the Porsche 911 Turbo.^[1]  Putting aside other reasons why one may want to buy this car, the main feature is the high-performance driving experience.  The enormous power, efficiently produced by the engine, is balanced with handling, braking, top-speed, and the durability to do it over and over again.  To take full advantage of the 40+ years of German engineering excellence, one needs to learn how to drive it, well.  Getting any car with a manual transmission and learning to drive it well would be a good starting point.  Learn to down-shift, apex, heel-toe, listen to the machine, and know its limits. Few people would know how to optimize the driving experience of the 911 without the assistance of a professional.

Only call 911 when all other options are exhausted

Renewable energy is much like the 911 in that it is expensive to purchase and best used when all else has been optimized.  In the case of the 911, the driver’s ability is the deficiency.  With renewable energy, the demand-side, or the “building”, is the deficiency.  Buildings almost always operate inefficiently.  The U.S. Department of Energy recommends reducing electric demand before adding renewables such as photovoltaic solar array (PV).^[2]  It turns out that it’s also cost-effective to do this and the resulting renewable system will be smaller in every way.

The process of retrocommissioning (RCx) does exactly that.  It looks at the existing equipment, controls, and operation, and optimizes it with low-cost controls, programming, and operational adjustments.  The efficiency projects that are considered for implementation in the RCx process have less than a two-year payback.  The first chart shows a summary of a few RCx projects Michaels has worked on compared with the installed cost of solar PV.^[3]

As seen, the cost of reducing demand, kW, through RCx is typically much less expensive than installing PV capacity, and that’s only looking at demand.  Reducing net energy, kWh, with PV also has seasonal limitations that RCx doesn’t.  For example, if a building in Des Moines, Iowa, installs a PV array to reduce summer demand, it can only reasonably expect upwards of 50% reduction in demand and energy savings in the winter months due to deceased solar availability.  The percent of maximum solar capacity over the course of a year can be seen in the second chart.

Be Practical and Resourceful

Every effort should be made for efficiency before buying a capital-intensive renewable system.  In fact, some utilities require it for incentives!  Use what is there before upgrades are made, otherwise it’s just conspicuous consumption.