The least expensive kWh is the one you don't use in the first place!

Big utilities build big, impressive generating stations and maintain a massive infrastructure. It's what allows us to run our entertainment systems, heat and cool our buildings, run our computers, etc. And we use...and waste...a lot of energy. Rather than spending a few more dollars on better glass that reduces solar gains, we design mechanical systems with more cooling capacity because it costs less money up front. Instead of installing high-efficiency lighting systems that reduce the heat gain in the building, we simply oversize the cooling system...because that's the way we've always done it. 

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There are many ways to reduce our energy consumption. Better insulation, more appropriate building orientation, energy recovery from exhaust air, a green roof, a white roof, waste heat recovery from air conditioning, refrigeration systems or process heat, integrating energy storage, etc. all can reduce energy consumption. And in a new project, working with the owner, architect and the rest of the design team in an integrated design process, it can actually reduce the first cost of the project, even though individual components may cost more. It takes more time to think through all of the implications of the changes, but it's possible to reduce energy consumption in buildings by 40, 50, 60 and even 70% when this is well done. 

By thinking through our designs it's possible to reduce the need for energy in the first place...without a lot of additional cost. If we don't consider these options, we force the utilities to continue spending a lot of money building generating stations, building expensive power transmission lines that no one wants in their backyards. 

EXAMPLE: We worked on a project recently that illustrates this quite well. Our client was building a 400,000 square foot (37,200 m2) store. The proposed lighting produced 2.25 W / square foot (24.2 W / m2) of heat. They had looked at a more energy efficient option that reduced the heat gain to the store to 1.25 W / square foot (13.5 W / m2)...a total reduction of 400 kW of power! If the lights were on 12 hours per day, that's over 1,728,000 kWh per year...for the life of the building! The problem was that it would cost about $500,000 to install the more efficient lighting. Looking at just the energy savings from the lights, the savings would be approximately $120,960 per year. A simple payback of about 4 years. 

Looking at the bigger picture: We were looking at the feasibility of installing a GCHP system for the client. I've talked about the importance of balancing the energy transferring into and out of the ground in other articles, so I won't bore you with it again...but the internal gains from the lighting added 400 kW (114 tons) of unnecessary peak cooling load to a GHX that was already very cooling dominant. By eliminating the load added by the lighting, it was possible to reduce number of boreholes and reduce the cost of the GHX by over $400,000. It was also allowed us to reduce the heat pump capacity by over 350 kW (100 tons) for an additional saving of about $100,000....a total cost reduction of the GCHP system of $500,000...enough to pay for the more efficient lighting. In other words, it cost the client nothing to install the better lighting. 

By looking at all the implications of a change, the client was able to save about $120,000 / year to run the lights. He was also able to reduce the cost of running the heat pumps by an estimated $30,000 annually, for a total energy cost saving of $150,000...with no additional capital cost.

Renewable energy proponents are not immune to the "bigger is better" mentality. To build 60 mW of solar energy production in Sarnia, ON cost $295 million. It produces 120,000,000 kWh of electricity and has an expected life of 20 years. That works out to a cost of over $0.12 / kWh. It uses over 100 acres of land to accommodate the solar panels. 

But if we can reduce energy consumption in buildings by simply spending more time thinking through the design of the building and the systems in them, we can make much better use of the electricity we are producing...whether it's produced by dirty coal or by solar panels.  It only makes sense!

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