en_secusol

After too many estimates but wonderful and very instructive conversations with installers, we have committed to going solar for our hot water. We got our shade report that tells us that our solar effect of 95.35% qualifies us for the State rebate (minimum requirement is 75%). Our solar fraction is 73.1% which means that solar will provide that portion of your hot water on an annual basis, but this is calculated on the average hot water usage here in New England, so I’m sure we’ll do even better.

Our greatest delay was figuring out what to use as secondary backup. The most straightforward was to run two heat exchangers through the hot water tank: one to the solar array, one to our oil-fired furnace. Obviously we looked into electrical backup alternatives because we have solar PV. These were (1) running the second exchanger to an  (electrical) heat pump, (2) a second, electrical tank, possibly on demand, (3) going with one heat exchanger and one electrical coil. But it turned out that our overproduction would possibly not cover the secondary energy needed and might even tip us over quite a bit. So after all that research we are sticking with the oil backup. If later on we want to change to electrical, it will be easy to refurbish.

As for more details: It’s a drain-back SECUSOL system, made by Wagner, with two flat-plate collectors and one 92 gallon tank. The installer is applying for a monitoring system (which the State would pay for), but as this system has already been monitored (and gets the highest rating), there is only a slim chance of getting it. Would be neat, though: we love data!

As for the cost, we’ll recalculate once the system is up (takes about 6 weeks), but if there are no surprises it will be $8000 - $2000 (State rebate: 25% of the cost up to $3500) – $1800 (30% Federal tax credit) = $4200. That’s much cheaper than the solar PV ($18,290 after incentives), but because we’re such frugal users of hot water and because there are no SRECS for solar hot water, it’ll take us longer to pay off this system (about 14 years versus the 8 for the PV).  It’s still worth it, though.

 

 

 

We figured we need to overproduce (produce more than we consume) about 100 solar KwH by August 13th, which will be a year from when our solar system was connected to the grid and we started producing. If we make it, we’ll have broken even. It will be a challenge, since as of next week our household will double in size. There will be six of us: DH’s parents and sister will be with us for the summer. But they’appreciate the challenge, I’m sure.

I’m working on a plug-in for the blog that will track the race.

Speaking of Solar Surplus and Countdown…

Here in Wayland we are running the Solarize Massachusetts program. This is a state-sponsored program developed by the Massachusetts Clean Energy Center (MA CEC) and the Massachusetts Department of Energy Resources (MA DOER) to encourage residential solar photovoltaic electricity (PV) installations.  It provides a framework for municipalities, homeowners and solar installers to work collaboratively to maximize cost-savings and energy efficiency benefits. It

  • Was only available to designated Green Communities (31 of 86 towns applied)
  • Was piloted in four communities in 2010, and is now extended to 17 towns
  • Provides marketing, outreach, procurement, and contracting support
  • Creates a group purchasing opportunity.  The price drops as more people sign up.
  • Ends on Sept 30. 2012

Wayland teamed up with neighboring towns Lincoln and Sudbury, adding up to about 13000 households. Each town assigned a solar coach (I’m the coach for Wayland) to lead the grassroots outreach. The MassCEC put out the Request for Proposals to solar installers and vetted the bids, then sent them our way. Together with specialists in the field, we chose an installer for the program.

What an opportunity! When I signed on for this, I knew this would be well worth my time. And I was appreciative of the MassCEC for engaging the grassroots in this. Just them, just a solar installer, or a combination of those two, would never have the impact of the grassroots that are already in place.

Putting systems in place for (and before) when they’re needed is one of the goals of Transition work. Cleanly, distributively and locally produced energy is one of those systems. The goal is to enrich Wayland with 100 solar arrays, 100 households that feel the empowerment of being of  producers instead of consumers, 100 households that will model a different energy culture.

Beyond that we are also looking into a Solar Community Garden, for those in our towns whose sites are not conducive for solar due to shading, orientation and other issues. The community building potential of this one is immense.

And beyond that, imagine a local mini-grid… We are laying some of the foundations here for one more element in our town’s resilience.

In the first year of its existence, Transition Wayland has primarily been doing a lot of little things: conversations, small manifestations, some skill building, lots of talking, getting to know our people. Lately we’ve stepped it up, with Earth Day (which attracted 400 visitors), and now with the Solarize program. It feels good to have a larger impact, to make a big change. Big changes in small places, they’ll add up.

 

I took this image two days ago. By now the snow is mostly all melted away. Two things catch my eye here. One: the panels, being black and smooth, shed the snow pretty easily. Two: the rest of the roof was still covered in snow, indicating good insulation.

This is a screenshot of our production a similar (not the same) day:

I’m so glad we went with individual inverters. If we had gone with one central one, then not only shade from trees but also snow on a few panels would have stopped harvesting.

You can follow our solar harvest here.

This is the Riot for the month of November 2011 for the three of us. Our first year’s averages were calculated here, our second year’s averages can be found here. Edson fixed the calculator: all go tither to crunch those numbers!

Gasoline.  Calculated per person. We drove to NYC and back for Thanksgiving. I walk Amie to school and back again every day, but activism necessitates more (local) drives than usual.

13 gallons per person

31.6% of the US National Average

Electricity. This is reckoned per household, not per person. After two months of not having to pay NSTAR (them paying us, instead) we got a bill again for  69 kWh (all wind). According to our solar meter, we produced 1403 kWh since the system was turned on, 274 kWh in November.  (You can follow our solar harvest live, here).

So in November we consumed:

274 (solar) + 69 (wind) =  343 kWh

17.1% of the US National Average

That’s quite amazing, one of our lowest numbers yet! And as you can see, we also made our first megaWatt last month and are well on our way to the next one! Those megaWatts are important because here in Mass. we can sell them as SRECS, which are the main component of the system payback.

Heating Oil and Warm Water. This too is calculated for the entire household, not per person. November has been crazy warm too, just like October. We had a few evenings of wood stove heat, but never needed the oil furnace backup for our “Annex” or for at night. All the oil consumption was for warm water (shower, dishes, laundry).

11.05 8.45 gallons of oil

17.9% 13.7% of the US National Average

{UPDATE} 3 Jan 2012: The way I have been calculating our heating oil consumption is by reading off the furnace how many hours it ran, then multiplying it by .85 because that’s the amount of gallons of oil I *thought* it used. Now DH just told me that our furnace is more efficient than that and the correct number is .65. Hence the correction.

Trash. After recycling and composting this usually comes down to mainly food wrappers.

10 lbs. pp per month

7% of the US National Average

Water. This is calculated per person.

376 gallons pp.

12.5% of the US National Average

This is the Riot for the month of September 2011. Our numbers were pretty stable here on the ole homestead. Mostly just the 3 of us. Our first year’s averages were calculated here, our second year’s averages can be found here. Edson fixed the calculator!

Gasoline.  Calculated per person. A trip to DC in it for DH, for work, and he carpooled, but I’ve no way to calculate that. I on the other hand am now walking Amie to school – and it’s just been wonderful! – so though I drive more for the activism, all in all I drive less.

22.65 gallons per person

55% of the US National Average

Electricity. First full month since the installation of our solar and our bill said 0 KWH!

Yes, we produced more electricity this month than we consumed!

The electricity company even gave us credit for what we produced over and above what we consumed. Turns out we do still have to pay something, though: not production charges (obviously!) but still delivery charges, because our system is grid-tied.

Solar doesn’t get as high a “percentage discount” (as a green technology) as wind does. De to the calculator being down, I was calculating it like wind, but now I have no excuse. So the percentage will jump a bit.  This is reckoned per household, not per person.

458 KWH (our solar) and 0 KWH (NSTAR)

25.3% of the US National Average

Heating Oil and Warm Water. This too is calculated for the entire household, not per person. During these warm months it’s basically for hot water, which is stupid.

8.5 6.5 gallons of oil

13.8% 10.5% of the US National Average

{UPDATE} 3 Jan 2012: The way I have been calculating our heating oil consumption is by reading off the furnace how many hours it ran, then multiplying it by .85 because that’s the amount of gallons of oil I *thought* it used. Now DH just told me that our furnace is more efficient than that and the correct number is .65. Hence the correction

Trash. After recycling and composting this usually comes down to mainly food wrappers.

10 lbs. pp per month

7% of the US National Average

Water. This is calculated per person.

511 gallons pp.

17% of the US National Average

Three days and a swarm of people and the solar array is UP.

But not up and running, yet. We still need the town to inspect the electricity and the building, NSTAR to approve the interconnection, to install the monitoring system, someone to commission the system, and us to be trained in its operation and maintenance. Another week or so…

But in the meantime, here is the info for our system:

Equipment

24 SANYO HIT Power Modules 100% of maximum power (Pmax) = 215.0 Watts / DC rate per panel 210 Watts / Total = 5040 Watts system

12 Enphase D380 module-direct inverters

Modules are placed in portrait orientation and racked as two rows of twelve modules each. Each row of modules is as a single string with six inverters, resulting in a total of two strings.

Production estimates

Estimated first year production in kWh: 4,735

This estimation takes into account historical weather data, the orientation of the south-facing roof and the tilt of the south-facing roof.

At this production rate, our solar fraction would be around 87% of our 2010 electrical consumption which translates to avoided utility costs of approximately $899 per year (this value is based on your current utility rate of $0.18 per kWh).

Value of solar energy harvested over project life: $ 50,922.89

Carbon Savings

Pounds of carbon saved in the first year: 7,103

Pounds saved over the project lifetime: 187,469

Cost (estimates, but close)

Base system cost: $ 35,558.00
Projected Commonwealth Solar rebate: $ 8,000.00
Invoice cost: $ 27,558.00
Federal Tax Credit (30% of remaining cost): $8,260
State Personal Tax Credit: 15% of remaining, up to $1000
Cost after installation: $18,290
minus yearly deductions beginning in year 1:
  • savings on our electricity bill per year: $900/year at our current utility rate of $0.18 per kWh > assuming prices don’t change, the system pays for itself in approx. 20 years
  • and we can sell 5 SRECS a year. At the moment SRECS are worth $520 each, but assuming the worst-case scenario with the lowest value per SREC at $285 each (so $1425/year), then the system is paid for in approx. 8 years.