Green House in St Michaels – Mid-April Update

Now nine months into our carbon net-neutral experiment, the house is still amazing.  It’s already generated about as much electricity as it’s consumed, and the remaining three months (mid-April through mid-July) typically have easy weather and sunshine.  Info from Choptank Electric Cooperative’s website tells the story so far (see attached chart):
– Starting from July 12, 2018, when our 50 solar PV panels went live, our electricity generation in the summer and early fall far outstripped power demand in the house, which was mostly for cooling and construction equipment.  Having a highly-insulated shell helped too.
– Then, this pattern reversed during peak winter months, when the low sun angle and even some snow cover made solar less effective.  Our 8-well geothermal energy system was seasonally less productive as well, but the house’s 45 SEER ground-source heat pumps still used much less energy than conventional heat pumps while also providing hot water.
– So far in late winter and spring 2019, our solar PV ‘powerplant’ is once again outproducing household demand, on average.
But even though the house is indeed net-negative in terms of energy use (produces more than it uses), we wonder if this means we’re also meeting our goal of carbon net-neutrality?  I suspect it does mean that, but we’ll need to use quarter-hour PJM fuel use data to prove the point, i.e., see exactly what fuels we’re displacing.  On the positive side, we can widen the circle and include carbon avoided by charging electric cars with solar power versus using gasoline cars.  We’ll also try managing our 3 Tesla batteries this spring to minimize carbon production, as discussed in last month’s blog – up to now, we’ve held these for emergency power supply in the winter.  On the negative side, there’s our prodigious lawn that needs to get cut weekly with conventional smelly equipment – we’re looking into an electric mower.  We’ve also got propane distributed through the house to gas fireplaces and the cooktop, but these are basically cosmetic uses, a few gallons per month.
Bottom line is we’ve got a zero-energy house, producing more than it consumes over an annual cycle.  We’re still gathering info to prove the same point for carbon, and we’ll also be able to assess the basic economics of this experiment, including years to pay-back and internal rate of return of our incremental investment.
As always, the devil is in the details!  More to follow.

Tesla Batteries, late winter solar energy, and more…

Our attempted-carbon-neutral home in St Michaels, Maryland, is now finished and we’ve moved into this most beautiful house! Energy bills are incredibly low – just paid our January bill to Choptank Electric Cooperative, $22.,,,and that’s the highest monthly electric bill since July, when the solar PV panels went live.  Awesomely low compared to other houses this size in the mid-Atlantic region, e.g., just paid $660 for gas and electricity in a comparably-sized, and well-insulated Bethesda house.  As we’ve pointed out before, this amazing savings owes to 50 SunPower PV panels, 8 geothermal wells with 45 SEER ground-source indoor heat pumps, and highly insulated walls.

On January 9, Tesla delivered our 3 PowerWall batteries and installed them on the garage wall.  Here’s the trio – Manny, Moe and Jack if you like – and Joyce’s Model 3 Tesla. .

Given the severe winter weather that’s ensued, we’ve kept the batteries topped off, relying on them mainly for emergency back-up.  Sure enough, they powered the house seamlessly during one brief outage in February.

PowerWalls charge preferentially on solar power, so it’s green storage, but also a green challenge. The question is how best to use them to maximize carbon avoidance. We’ll start next month by experimenting with different modes to time-shift loads. Initially, we’ll use them to abate steep evening ramp-ups in energy demand that follow sunny days, much as major Li-Ion battery installations are used in Southern California. The idea is that PJM uses its most polluting generators to meet this need, so we target the batteries to avoid that. Another pattern will be to use them to meet our mid-evening demand using stored solar power. Yet another will be to preferentially charge the EVs with solar power. Only with a more complete understanding of PJM’s marginal fuel at each 15-minute interval will we be able to maximize the effectiveness of our batteries in avoiding carbon emissions.

Meanwhile, the “power plant on the roof,” combined with a low-energy-demand house, is amazing. As the days grew longer, we’ve found that by late February we’re now steadily putting more energy into the grid than withdrawing on sunny days. Snow cover has been less of a problem than we thought – despite their nearly zero-degree angle (flat) mounting, it’s been taking only a day for the snow to melt away and for solar energy production to be restored.

More to follow!

Autumn Rains!

Here are three views of our construction site on a nice day in September.  Otherwise, it’s been spring rains, summer rains, autumn rains – so far 2018 has been one of the wettest years on record here in the Mid-Atlantic region.  The incessant rains have definitely slowed construction and limited solar output.  But, nevertheless, our amazing team completed the house yesterday, about a week ahead of schedule!  So now, we’re dealing with the paperwork, yard clean-up and grooming, and some landscaping.

Here’s the energy picture:

1)     Solar and geothermal – and major insulation.  Rains have severely reduced solar energy production, but on even partly sunny days, energy use has been balancing out this fall – and that’s with HVAC and hot water systems, the kitchen, and lighting all up and running!  Energy efficiency is why this is working, i.e., 45 SEER geothermal heat pumps, immense 6” insulation, LED lighting throughout, and more – and all in spite of suboptimal orientation of our 50 SunPower panels, which are hidden from view on flat sections of the roof, see above pix.

2)     Three Tesla PowerWalls.  Still waiting, but Talbot County recently approved their installation, so hopefully won’t be long now.  This house is on-grid, not off-grid.  But still, we’ve sized our battery storage large enough to let us use all excess solar energy during evening peak periods and at night.  Also, together with the solar panels, the PowerWalls will serve as our emergency back-up generator in case the house loses power (which hasn’t happened in the 19 months since we bought the property, as far as we know).

3)     Electric cars.  Once we’ve got our Use & Occupancy Permit and some furniture next week, we’ll move in (Yes!) and try charging the electric cars.  Will charge them during daylight hours so they’ll be running on solar energy, versus PJM’s coal-dominated daytime energy mix.  Then, on evenings after charging the cars, what happens depends on season – on winter nights, the house will probably need to use electricity from the grid, which at that point relies mostly on high-efficiency natural gas turbines; on summer nights after charging the EVs, we expect the PowerWalls will hold enough solar-generated electricity to make it till dawn without buying electricity.

What did all this cost, and will it ever pay back?  How much carbon are we preventing from entering the atmosphere, and what’s our per-unit avoided cost of carbon?  Will we actually be carbon neutral?  Stay tuned.  We’ll know once we’ve gotten a full year of operations under our belt.  At that point, we’ll do the analysis and hope to present results at the November 2019 USAEE-IAEE North American Conference in Denver.

Meanwhile, another post will follow as soon as our batteries are up and running.

Mid-August Update: Geothermal Start-Up

We’re getting closer! Our attempted net-carbon-neutral house in St. Michaels, Maryland, won’t be finished for another two months, but its energy systems are now starting to spool up. Although it’s still too soon to report any systematic results, data reported on our utility and solar provider apps look promising.

This month’s illustration (attached) is a snapshot of the past few days from our page on Choptank Electric Cooperative’s website. The indication is that our 50 SunPower solar PV panels have continued to overproduce electricity, which we’re selling back to the grid via Choptank (also see last month’s report). Then, this past week, we started up our 8-well geothermal ground-source heat pump system. Things changed a little (see sawtooth pattern in the figure) but this still looks highly positive – i.e., we’re producing from solar energy much more electricity than demanded on site, even despite enjoying a nice, cool house in 90o weather!

Preliminary, it appears likely that electricity produced by our panels will continue to more than meet the house’s space conditioning and water heating energy demands. On sunny days, this will be especially so, including around the clock after our three Tesla Powerwall batteries are delivered and installed – but on dark, cloudy days, we’re unlikely to make HVAC ends meet without buying electricity from the grid.

Looking ahead, we expect our electricity uses to increase after our kitchen (mostly electric) is installed next month, and after the house lights up at night in late September, and as soon as we move mid-October and plug in everything, including the cars! With all this, if our solar panels are still overproducing, then we’ll keep selling the excess back to the grid. We should have a reasonable indication in another two months or so.

Sometime in 2019, we’ll be able to present results on a more systematic basis in terms of pay-back periods and the project’s implicit avoided cost of carbon.


Solar panels went live July 10 at 4:12 PM…

So far, we’ve produced a surprising (to me at least) amount of solar energy in our first week of operation.  According to Choptank Electric Cooperative, we averaged 90.9 kwh/day, ranging from 61.0 to 107.6 on dark and bright days, respectively (standard deviation = 16.5 kwh/day). Choptank’s hourly report of the first 8 days is shown here (sorry a little hard to read).  The red area is each day’s net quarter-hourly delivery of electricity to our house – this is mostly minus because we’ve been producing and delivering lots of energy to the grid since going live on July 10th.  We’re real pleased with this level of production, as is our vendor, Sunrise Solar of Chestertown, MD, especially since we opted for aesthetic reasons to orient our 50 panels flat to the sky, which is far from optimal, as described below.  Also pictured here is Sunrise Solar’s drone shot over the house, which is still under construction by the painstaking and methodical people of Paquin Design/Build, especially Paquin’s foreman, Kenny Seeling.  Kenny recommended Sunrise Solar to us, and we’d recommend in turn both Paquin and Sunrise to anyone, as well as Charles Paul Goebel, our architect. In addition, Erin Paige Pitts of Annapolis is creating unbelievable interior spaces.
Looking ahead…
Paquin has now moved our HVAC systems into place, two 4-ton ClimateMaster 45 SEER geothermal ground source heat pumps . We’re hoping In the next month or two to turn the system on so we can get a sense of what our electricity demand will really look like, sans the kitchen, lighting, etc. Maybe 90 kwh/day will cover us once our batteries arrive! More to follow…

Invisible solar

June was a key solar energy month for our project – Sunrise Solar of Chestertown, MD installed 50 SunPower 360-watt panels on the roof (here they are, at work).  Residential solar is becoming fairly common these days, but we had a slight twist.  We’d hoped to have a Tesla solar roof so you’d never know there’s a powerplant on top of the house – but it became clear that Tesla’s solar shingles wouldn’t be available when the time came to get a roof up there.  So instead, we found another way: our architect, Charles Paul Goebel of Easton, MD, designed two flat roof sections large enough for all 50 panels, and so now you hardly notice the rack unless you’re really looking for it, as the before-and-after pix show.  Phenomenally neat work, Sunrise!
Present status: we’re expecting to receive final sign-off from our local utility, Choptank Electric Cooperative, and then we’ll start solar-powering our construction site and a maybe a neighbor as well on the same transformer during the days!  We realize our flat-to-the-sky solar panel orientation isn’t as optimal as tilting them would have been, but we’re still hoping our system will produce enough electricity to run at least the kitchen and one of our geothermal ground-source heat pump systems as needed.
Next month, we’ll turn on the HVAC system and see how all this plays out.  More to follow!

Spring Rains!

Building a new home in rainy Mid-Atlantic springtime weather – energy innovative or otherwise – involves mostly indoor work. So in May, it’s been carpentry, plumbing and electrical pre-installs, insulation, drywall, pre-ordering fixtures, and more carpentry. Our energy systems work will follow in June and July, with solar panels and the local utility grid interconnection, and HVAC equipment placement. All this is the sleeves-rolled-up part of any home-building project. We’re blessed with a great team, see below, who all work well together and really come through at a weird time like this, when we’re still partly on paper.

Late April-2018 progress report

Work continued on our attempted carbon net-neutral home in St Michaels this month – most construction activities were routine, e.g., inside-the-walls inspections, porch stone flooring, and the like. Re our six energy goals:
• Geothermal wells are completed.  All eight are now hooked up to the house where two ground-source heat pumps will be located indoors, basically quiet, so one in an upstairs closet & the other in the basement. Some wells are as far as 100’ away from the house. Delighted they’re invisible, so that kids can play ball on the lawn and never know they’re down there, providing most of our HVAC and hot water energy.
• Our local utility, Choptank Electric Cooperative, set a two-way meter, and our solar energy firm, Sunrise Solar, has prewired and set a pre-switching system (visible next to meter) for 50-panel rooftop system.
• The second battery-electric car arrived – a white Tesla Model 3, somewhat smaller and a lot less expensive than the Model S, but still racy, comfy, and has a 310 mile range.
• No progress on battery storage Powerwalls or the marine biodiesel motor yet – these will take us a little longer.
More to follow next month!

Geothermal drill

With house 50% built, out there today drilling eight 220′ geothermal wells.  Three completed as spring arrived 3/20/2018!  How much technology has transferred from natural gas well drilling in the U.S.?  Plenty!

Net-Zero Carbon Home and Cars Experiment – Highway to the Future or Costly Will-O’-The-Wisp?

Part I – Defining the Experiment
Disclaimer: I’ve been a natural gas expert and enthusiast for decades – none of the ensuing diminishes that in the slightest.  Natural gas will be around for decades, powering our homes, buildings, factories and cars.  We’re only trying to move the ball down the field!
1. The lure.
Joyce and I are building a home in St Michaels, Maryland, that will balance three basic goals – beauty, functionality, and environmental compatibility.  In that order.  The beauty part means living by the open water in a Charles Paul Goebel designed home with an Erin Paige Pitts interior – among the best designers in the business.  The functionality goal drove us to our wonderful designers, but also to local builder Brent Paquin and his experienced, practical, dogged crew.
For environmental compatibility, we had only ourselves to turn to.  With helpful tips from our designers and builder, mentors to the project, we set out to carry out our project in a series of steps that we could defend as arguably the best we could do, in light of the three sometimes inconsistent goals – beauty, functionality, environmental compatibility.
2. Decon
Deconstruction.  We purchased a lot in St Michaels with an older home already on it, owned by the late Rev. and Mrs. George Evans.  Rev. Evans served as chaplain of the U.S. Marine Corp, and we wanted to honor his service and homesite.  Rather than tear it down, we sought to deconstruct the house, literally dismantling it down to (but not including) the floors, siding and rafters.  All was donated to the Choptank Habitat for Humanity.
Deconstruction is a pretty new field, and practitioners are hard to find, and harder to schedule, so this process took up about a month, which we’re told is fast.  Thanks to local contractor Pete Bailey.
3. The plan
The house is now (March 15, 2018) about half completed, and the trades are underway – rough-in plumbing, gas (propane), low and high voltage electricity.  Over the next two months, our plan is to carry out these steps:

a) Geothermal – drilling 8 wells of 220 foot depth
b) Ground-source heat pumps, SEER 45, about as efficient as the market will offer today
c) Rooftop solar – 50 Sunpower high-efficiency 360-watt panels, thus 18 kw.
d) Battery storage – 3 Tesla powerwall battteries, enough to power the home through the night and, together with the solar panels, hopefully beyond in emergencies
e) Battery electric cars (not hybrid) powered by solar energy to the extent possible
f) Biodiesel motor for boating

In forthcoming blogs, we’ll report on each of the foregoing steps – economics and implementation, costs and benefits, and effectiveness in providing energy to the home and doing so without emitting carbon.  Watch this space!