Showing posts with label footprint. Show all posts
Showing posts with label footprint. Show all posts

Friday, March 18, 2011

Electricity metrics: Driving the wrong behavior!

I am working on some energy reduction projects at work. One potential project is to improve the efficiency of some of our equipment, so it uses less electricity.

The problem is that the savings don't actually reduce our electric bill, but it does reduce the electricity that our energy provider would have to supply to us. Let me explain...

First, I am not an electrical engineer, so if I state something wrong, please go easy on me, as I'm attempting to speak in layman's terms.

This has to do with something called "power factor". Basically, the electricity provider has to generate more power for its customers, if the power factor on equipment and machines are lower than ideal (less than 100%).

Poor power factors are typically caused by older equipment, or over-sized motors, or equipment with internal problems or poorly designed. You can learn more here: Wikipedia: Power Factor or a simpler explanation at Washington State EnergyIdeas

Most people at at their home pay for the amount of kilowatt hours consumed per month. Same with companies. However, the electricity provider has to provide enough power to cover the "apparent" power, which is usually more than the actual kilowatt hours (KWH) consumed.

For example, let's assume I have a refrigerator that consumes 10 KWH per day in my home. If the power factor is poor, then I might actually be consuming more like 11 KWH, which is what the electricity provider has to supply to my house. The extra 1 KWH is released as heat into my house and essentially wasted.

So I pay for 10 KWH, but I actually used 11 KWH. I don't actually directly pay for the extra 1 KWH that I needed, due to my poor power factor. So if I fixed my refrigerator so the power factor was improved, and I now consume exactly 10 KWH (instead of 11), my electricity bill doesn't go down. There's no motivation for me to save electricity by investing in some upgrades to improve the power factor.

For large companies, there are extra fees that are charged if the overall power factor is too low (say below 85%), so the utility companies attempt to cover their costs that way. However, usually the fees are charged depending on what range of power factors they fall within.

For our company, we fall within the middle of the range, so we would have to invest in significant improvements to power factor in order to see a benefit on the bill (the point where the extra fees would be removed). Since it is unlikely that we will make that large of an investment, we have decided not to pursue those opportunities. Usually this involves installing a capacitor bank, which stores the energy and reduces the loss of energy.

So here's the issue: Because our company is not charged by the utility company for the actual amount of electricity we require, there is no financial incentive for us to do the right thing by improving the efficiency of our equipment (other than reducing our carbon footprint). The solution would be to charge us for the apparent power (11 KWH in our home), instead of the actual power used by our equipment (10 KWH).

Just another example of metrics driving the wrong behavior!

Monday, March 29, 2010

Rockwell Collins goes green with LEED buildings

I had the opportunity to tour one of the LEED certified buildings on the Rockwell Collins campus in Cedar Rapids, IA. The older building of the two is Gold certified, and the newer one is Silver.

 

At the beginning of the project, they discovered that many LEED buildings cost around $250 per square foot. They were able to complete the 120,000 square foot pre-engineered building for less than $100 per square foot. The additional investment in obtaining LEED certification, and the enhancements required to achieve a high enough score, had a payback of about one year. Therefore, in the 2nd year, they would start to see cost savings, compared to a non-LEED certified building.

 
Some of the cool features that are included in these buildings include:
  • 99% of construction waste — more than 1,000 tons — was diverted from the landfill
  • Building footprint covers only 2.75 acres, and nearby pond was incorporated into the design
  • More than 30 dedicated parking spaces for low-emissions and fuel-efficient vehicles
  • 40% (385 gallons) of water use reduction through waterless urinals, dual-flush toilets, rainfall capture on roof, etc
  • Exceeds ASHRAE 90.1-2004 minimum energy performance requirements by more than 20%
  • More than 15% of building material is recycled content
  • Energy Star reflective roofing
  • Lots of natural light to minimize need for lighting, and lights are on timers and motion sensors to reduce costs when left on
  • Energy efficient windows with shades to reduce heating effects
  • To reduce driving and wasted time to get to the main facility (headquarters) across the street, a shuttle vehicle was setup that runs every 5 minutes
  • Chaning rooms and showers to encourage bike riding
  • Optimized parking lot lighting
  • Low VOC paint and coatings, and carpet contained recycled content
  • Xerascaping (native plants) deployed to minimize amount of water usage
  • Variable frequency drives (VFD) installed on equipment to reduce electricity costs of large equipment, part of larger energy management software system
The cafeteria is also very modern, clean and open, with access to the outside, so employees can eat with visitors, or just enjoy the weather. There is also a nice walkway near the pond, which is located between the two buildings.

 
 
 
As an employee, if you need a break from work, try hitting some putts in the break area, or put together a puzzle.


To learn more about this project, visit the Ryan Construction website.