The Advantages of Neighborhood Photovoltaics

Here are three reasons to like PV mounted on Denver houses, even though it's expensive:

1.  Transmission losses - - Although grid-tied PV needs a functioning grid, most of the PV kilowatthours generated at a PV-equipped house stay in the neighborhood and aren't diminished by transmission losses which are usually quoted at 30%.

2.  Autonomy - - Let's say you are building a spec house that you want to have low net energy usage.   If you install PV, you have added value to that house.  If Xcel invests directly in wind energy, that doesn't help you or your buyer.

3.  Utility power outage avoidance - - Once PV market share reaches a crucial point, the Xcel will see the potential of outage avoidance that distributed PV inherently has.  At that point they will start providing direct inverters and distributed batteries.  Utilities receive big rewards for reducing outages.

In Colorado, Xcel is required by law to reach 30% renewable energy by 2020.  Neighborhood PV is one of the top 3 ways this will happen, partly because it's easy and incremental compared to larger, more cost effective but cost intensive measures.

Is a Renewable Energy Portfolio Standard an artificial incentive?  Of course it is, but until a carbon tax is implemented, there is no other incentive to reduce the use of fossil fuel.

DOE Proposes "Home Energy Score"

The recently released DOE proposal for home energy ratings is getting closer to what's needed.

As I mentioned last month, the LEED system falls short of usefulness, and the best rating should be in dollars.  The DOE system is in dollars, all right, but they are unfortunately using savings, not cost.  Home size and "average energy cost of a home without upgrades" needs to GO AWAY.  Give us a standardized yearly energy cost for this house, period.   It's much simpler, and ultimately much more useful for everyone.

Should We Regulate the Size of Homes Because Big Ones Aren't Sustainable?

This debate is really simpler than it seems. Dollars are the units with which we can measure and compare everything in a home’s cost. The home uses more land? That equals more dollars in purchase price, property tax, storm runoff fees, etc. It uses more resources to build because it’s bigger? Well, it costs more. The only thing that can improve the accuracy of dollars is a carbon tax that is allocated and implemented perfectly. I realize that won’t be easy.

Recurring costs are a little more difficult. That’s why the EPA created a standard MPG rating for cars, and the Energy Guide rating for major appliances. With them, people could compare their future costs of operation of their purchase against the other competitive products.

I submit that the only worthwhile rating system for homes will be in dollars per year. An accurate HERS score can be converted to $/yr with a standard set of conditions.

Another significant metric for a house is the cost of transportation incurred by the residents. Walk scores and other ratings can be standardized and converted to $/yr, and reported on the MLS. This is already starting to happen.

Now, with a purchase price and a $/yr rating in hand, the consumer will be motivated to buy small, because it’s cheaper. If they can still afford a 3,000sq.ft. house, they should be able to buy it, there is no reason to put an artificial cap on size. Markets forces work well if the consumer is educated.

Unfortunately, LEED scores and Energy Star ratings are a confusing mess: http://greenbuildingindenver.blogspot.com/2010/10/leed-for-homes-rating-system.html

The Location of Your Low Energy House

Well it's the Denver area, yes, but what makes a low energy location?

According to this article the location is the MOST important factor in low energy homebuilding:  "Households in downtown Chicago produce one-quarter the greenhouse gases of households in nearby suburban Kane County"

What if, all of a sudden, say, like, in 2011, "production" homebuilders stopped concentrating on tearing up farmer's fields and building new infrastructure for new housing, and started concentrating on rebuilding run-down neighborhoods closer to the city center?

Hmmmm..........

Just possibly the biggest single step toward halting global warming. 

As mentioned before, the trend has begun on vacant lots in Philadelphia.  Philly has a strong enough economy to support infill like this.  But we're not seeing much of this anywhere else in US.  In the rust belt, where vacant lots are available, cities like Detroit are on life support.  Job growth is really the only driver of new construction.

Denver has a little bit of job growth, and homebuyers are learning more about these issues everyday.  One day in the near future, a young pregnant couple will contact a neighborhood redevelopment company in a neighborhood like Villa Park and not even think of taking a drive out to the Wheatlands , even though the prices are tempting.

Stay tuned.

Water Conservation in Denver

I've not posted any prior recommendations about water usage, primarily because I'm an energy engineer, not a water engineer.  However, I was reading something the other day that said Denver's water usually beats out bottled water in taste tests.  Elsewhere, I read that 60% of our water usage is for landscaping.  WOW.  We residents are thoughtlessly spraying the best drinking water in the WORLD on our lawns.

Then the announcement came that our water rates may increase sharply , so I figured it was time for a post about water and a long-term experiment of mine.

For fun and profit, I invest in Denver real estate, so water costs and landscape maintenance costs are very important to me.  Therefore in 2005 when we acquired a house with a dead front yard, we decided to till out the weeds, place down weed barrier, and cover it with mulch.   For the whole front yard, this cost $450 including mulch, and took one day with two laborers.  In recent years, free mulch from recycled trees has become common.

This simple project saves about $140/year in water, and $200/year for mowing and maintenance.   This particular yard doesn't look nice, but there are no weeds at all:

  A dirt yard doesn't look any good either, but you still have to mow the weeds that sprout it if you have a rainy spell, and you get a lot more mud tracked into the house:

We've also experimented with a few drought tolerant plants, and found cactus can be grown without a drip watering system.  Pea gravel makes for a better play area and lasts longer, but it is more expensive than free mulch.

History Lesson:

During the drought of 2003, Denver Water (DW) begged us to reduce water usage, and invoked  watering restrictions that we followed successfully enough to reduce overall usage by over 40%.   DW promptly rewarded our diligent efforts with a sharp rate increase.   See, when the number of gallons of usage goes down, the infrastructure and management costs of water distribution must go up on a per gallon basis.   Gee thanks, DW.

The LEED For Homes Rating System

I've been watching from the sideline, stubbornly NOT going for LEED qualification. In building code terms, LEED is far too prescriptive and not performance oriented. Throw in "too complex for real customers" and too expensive, and what you have is nearly worthless.

Here's a solution I've been mulling:

1. Let the building departments adopt the 2009 energy code as they wish. Then STOP any code changes forever, except for safety items. The technology is still changing too fast to attempt to follow it with prescriptive code "improvements". Another reason for freezing the code is to prevent those pesky unintended consequences that aren't even discovered for 20 years. (see Solar Driven Moisture in Brick Veneer at BuildingScience.com)

2. Then let builders build as they see fit. Good ones will keep improving the sustainability of their product. (If you care enough to be reading this blog, you're probably one of the good ones)

3. Here's where we replace prescriptive with performance: You can't get any sort of LEEP (Leadership in Energy Efficiency Performance) rating PRIOR to building anything. To get a LEEP rating, the home must have a simple Web-based monitoring device installed for at least one year. The cost of this should only be $1000-$3000, it only needs a handful of measurements, some of which are already there, like kwh consumption, water consumption, gas consumption. Add two indoor temperature readings, hot water tank inlet and outlet, outdoor temperature north side of house and south side of house, major appliance electricity consumption, etc.

This data can then be used to "normalize" the performance results. The square footage of the house is completely left out of the normalization calculations.

4. The LEEP rating is in dollars, the only unit that makes sense to everyone. (Just like a yellow EPA EnergyGuide label for appliances). A true net zero energy house gets a LEEP rating of $0/yr. If you put on excess PV panels, and the utility pays you for your excess production, then your LEEP rating can be calculated to equal what the utility pays you for the year, and is negative, say -$200/yr. A 1000 sq. ft. home built to 2009 code minimum might get a rating of $800/yr. A 2000 sq. ft. home built to 2009 code minimum should perform a little better per sq. ft. than the 1000sq.ft. home, so it might get a rating of $1400/yr.

This performance rating will always guide the builder in the right direction.

5. The other non-energy efficiency related metrics can have their own rating, such as LEEPdurability, and LEEPwater. A near-zero maintenance house might have a LEEPdurability rating of $30 per year, while a house that needs painting and new light bulbs often would be rated at $300/yr. Again, the LEEPwater rating is in $/yr. Oh yeah, don't forget LEEPembodiedenergy. That could be in kwh.

The ratings are thus understandable, simple, standardized, and allow the builder his own solutions rather than any suggested by LEED.

Eventually these ratings will be meaningful to buyers, and that's when the builders learn they must generate good ratings. That's what I like, market forces in play instead of federal policy!

Since this is so similar to the appliance rating program, the LEED officials must have studied the method, but I can't figure out why they rejected it.

The 100k House in Philadelphia

I've been a fan of the 100k house website for almost 3 years. Chad Ludeman has created an innovative home building and marketing business model, an accomplishment that no large builder in America could ever do.

One recent post sums it up: High Performance Houses

They've nailed it, pure and simple. Contrast it to a subdivision that was nixed by Golden. Golden has no idea of what it really wants, but they had this feeling they didn't want this. Over time, they'll understand that they want 100k houses and neighborhoods.

Does anyone else besides me think Denver is ready for something similar to 100k? The biggest difference in the two markets is that Philly has thousands of low-cost vacant lots ripe for redevelopment. In Denver, a vacant lot in a good neighborhood doesn't exist, so scrapeoffs in lower tier neighborhoods may be necessary. Let's finish the infill process in Denver and scrape or renovate worn-out houses as required before we tear up irreplaceable open space in Golden.

Their list of innovations really covers every phase of the business, except maybe the use of realtors. Lots of folks thought realtors would become obsolete because of the internet, and it just hasn't happened, and doesn't look like it will happen. Postgreen (the 100k development company) however, has pre-sold a high percentage of their homes. This means that they haven't really needed the conventional realtor relationship.