LIGHT IT UP WITH GREEN ENERGY!
Recently I attended a great seminar produced by energy consultant Sean Tobin, Optima Engineering, and Southern Energy Management. I’ve attempted to summarize some of what I learned below coupled with my past experiences and posts. I left an even bigger fan of solar and geothermal and with greater knowledge of the pros and cons of the many green rating systems out there. The issues are complex and the numbers vary, but these are the big ideas.
THE BUILDING ENERGY ISSUE
BUILDING ENERGY, FUEL, EMISSIONS
Worldwide buildings contribute more than 45% of all man-made CO2 (carbon) emissions which in mass has detrimental effects on the earths atmosphere ozone layer that helps protect us from the radiation of the sun (leading to global warming). The remaining carbon emissions is divided between 35% transportation (cars) and 20% manufacturing.
Buildings consume 72% of the electricity produced (from power plants) in the U.S. Manufacturing primarily consumes the remaining electricity produced.
Most energy in the U.S. is fueled with non-renewable resources (eventually we’ll use them all up). Our fuels breakdown like this: 22% Coal, 25% Natural Gas, and 38% Petroleum. The U.S. uses about 10% Nuclear energy and 6% Renewable energy (solar, wind, and hydro).
U.S. buildings consume about 13.6% of potable water annually. The average american uses about 64 gallons of water per day (check your water bill).
About 0.37% (less than half a percent) of the water on earth is available for human consumption and sanitation (90% of this is in underground aquifers). The rest: 97.5% is salt water, 1.6% is locked in glaciers, and the remaining 0.53% in plants, animals, and atmosphere water vapor.
HOW MUCH ENERGY DOES MY BUILDING CONSUME?
Your building’s Energy Use Intensity (EUI) is measured in kBtu/Sq.Ft./Year. Refer to column 5 (Median Site EUI) in this chart, or for residential this chart for a mean annual consumption baseline based on the type of building .
You can use the Energy Star Target Finder to refine your numbers - this also works great if you already have an operating building or home with utility bills to input as a way to measure your performance.
Note - determining how much energy your building will use gets complex quickly. If you’re designing a new building, the above charts can serve as a big picture baseline. From there you’ll need to do some type of energy modeling to determine how much you’re design will use. Some sources: Energy Star (COMcheck, REScheck, Manual-J), Passivehouse.us, Green Globes, USGBC, or any number of software programs. A professional energy consultant or mechanical engineer is recommended to help refine. If you are a homeowner some utility companies will offer very basic check services.
HOW CAN I CONSUME LESS?
PASSIVE SYSTEMS FIRST
1. Increase your R-value - increased wall and roof insulation, insulated glass units, low-e glass, less glass.
2. Shade south facing glass to reduce solar heat gains in the summer.
3. Mind the details and seal all joints to avoid conditioned air loss.
4. Use LED or Fluorescent lighting - they use much less energy than incandescent - roughly between 50% and 75% less energy for the same lumens (light level).
1. Geothermal - uses the earth as a heat-sink to reduce the temperature change required by your air-handler - this means less energy required to heat and cool, on average somewhere between 30% and 45% less energy for heating and cooling.
2. Solar Photovoltaic Panels - produces onsite electricity - how much is dependent on your building. Installation costs have fallen dramatically and efficiency has vastly improved in recent years. As of 2013 it’s now reached the bottom and is as good as it’s going to get for some time to come. There are options for panel direction and angles. You can install panels facing south, southeast, and even east and still get 77% collection. Consult an installer to analyze your building and site potential.
3. Heat Recovery Ventilation (HRV) or Energy Recovery Ventilation (ERV) - supplies outside fresh air mixed with the tempered air already in the system adding to air-quality and overall efficiency - know your climate and system first.
4. Rainwater Harvesting - collect water from your roof, store it in a tank, filter it, and use it for outside irrigation and flushing toilets. It’s free water!
WHAT’S IN IT FOR ME?
SAVE MONEY THROUGH LOWER BILLS
In the long run you’ll pay less to operate your building or home. You can determine exactly what you save through energy modeling.
MONEY BACK NOW - TAX-CREDITS
Depending on where you live there is a combined 65% +/- tax credit available for installing energy efficient systems (solar, geothermal, etc). For example, if you paid $40,000. for your geothermal system, between your state and federal taxes you can deduct $26,000. from your tax liability (at once or over 5 years) - that’s $26,000. back in your pocket - what a deal! This is currently in affect until the end of 2015 for most people. If you are a business owner, in addition to the credits you can depreciate the solar and geothermal equipment costs on your business taxes - wow!
A BETTER BUILDING
Better health and comfort for the people inside.
SIMPLY GOOD EARTH STEWARDSHIP
WANT TO KNOW MORE?
The act of building anything inherently requires energy and will use, alter, and destroy something. The most sustainable thing you can do is not build anything. Short of that we can work toward balancing our buildings through renewables, recycling, and reusing.
SEE OUR PREVIOUS POSTS
ARCHITECTURE 2030 - the big picture and resources.
THE 2030 PALETTE - real design stuff to help get your there.
ENERGY STAR - a basic energy program.
LEED / USBGC - industry leading green building program (encompasses energy plus lifestyle). LEED energy is predicated on energy mean baselines (ASHRAE 90.1). Note that ASHRAE 189.1 is higher standard for Green Buildings. These standards provide baselines and targets for multiple building assemblies (usually you're consultant will work with these inputs).
PASSIVE HOUSE - NOT just house! Also encompasses commercial buildings. The approach here is the building itself can reduce the need for electricity in the first place.
NET-ZERO ENERGY BUILDING - There are only 10 certified net-zero buildings in the USA. Net-Zero means a building with greatly reduced energy needs through efficiency gains such that the balance of energy needs can be supplied with renewable technologies. Inputs equal outputs. This is not LEED. For Net-Zero details check out the National Renewable Energy Lab, and the manual (note there are 4 different net-zero classifications - yep).
Book: Net Zero Energy Design by Tom Hootman - a guide for commercial architecture.
LIVING BUILDING CHALLENGE - this the Uber-Vegan / Raw Dieter of green building. There are 9 certified buildings.