Energy Transition and Resiliency

[Burnin Up]

My household has been working on the 10 year plan for energy transition and resiliency. Prior ten years were spent analyzing energy use and engaging in conservation at every possible point. Would like opinions and guidance on current status and future plans.

Back story
Way Back in the Spring of 2011, I was looking to put in a wood stove to reduce my oil use. Old posts looking for stove advice are still archived on this site. Anyway, the wood stove didn't happen but solar PV and insulation upgrades did instead.

Where we are now.
House currently still has an oil boiler, baseboard radiators, installed by PO in 2000.
Central AC (nearing the end of its life cycle, needs recharged every year) installed in ???
4.6 kw PV, installed Spring of 2011. (link to public monitoring below)
http://tinyurl.com/q6xtjwa
PV covers the nearly all of current electric use to date.
Mitsubishi HyperHeat Mini split installed in July 2014 (for zoned AC/Heat)
I am hoping the mini split will take a bite out of the oil usage. It certainly helped with cooling the whole house this summer. I expect that the mini split electricity use exceed my PV production.

Where we want to be.....
Would like to be nearly fossil fuel free, but also have redundancy in power supplied to the house. Thinking about an electric car to replace the current ICE (14 yr old Toyota). When replacing the roof, adding more PV to max out my southern exposure, which should help with the mini split and EV load demand. Also NEED a plan for emergency backup power.

The rest of the ten year plan includes two economic challenges. A new roof for the house. (not the garage with the solar array) and a new vehicle. I have been thinking about what is the next step in this process.
Current roof and car are still good and working just fine, so I am looking at backup power.

I have a couple of electricians lined up to come and give estimates for propane generator. After last winters no power for >1 week, redundancy in power supply has become important. I know it means adding another fossil fuel to the mix and honestly I am torn about that, but at the present time PV battery storage is the least viable for backup due to the cost and maintenance. (Come on Tesla, hurry up and produce that 65 KWh battery for less then $200/per kwh!) LOL

Okay everybody, that is the situation. What are your thoughts?

Burnin Up

 

[woodgeek]

Welcome (back).

I had an older, poorly insulated house with an oil boiler and oil hot water. We differ in that I don't have a solar-able site (totally shaded), but I did recently lease a Nissan EV. I have reduced the BTU load for heating my house nearly 50% since I bought it, by airsealing and insulating. I ditched the oil altogether and went all electric, sourced from wind. That is, a 4 ton split ASHP and a 80 gallon Heat Pump Water Heater, HPWH.

I lost power too in the ice storm, and in Sandy. I have an older woodstove that can heat my house as a backup. I decided that money spent on a really $$ generator was a waste, so I went minimalist. In my case that is a $100 Harborfreight, gasoline powered two-stroke genny, that powered me for 3.5 days after Sandy, and 4.5 days after the ice storm. It maxes out at 700W, but that is enough to run my sump, wood stove blower, refrigerator, wifi, portable electronics and a few cfl lamps. (I have to pull the fridge when I am running the sump load). Runs about 1 gallon of gas a day, have a measly 5 gallons on hand, stores >1 year with additive.

So, see how you do with the mini this winter, and either keep tightening up the house or buy a second mini next year, and ditch the oil. Get a HPWH and go all electric. Looking at $5-8k to do that, prob save $1.5k a year in energy bills, net. Before you pull the oil boiler, get a cheap new woodstove, or get one off craigslist in good condition, for backup heat. And get a little genny and you will be ready to rock and roll after the next Super Ice-ercane or whatever. IF leasing an EV is not to your tastes, wait a couple years for the Leaf Gen2 or Tesla Model 3, or their competitors, which will all be superior to the current offerings (one reason I leased).

 

[Fi-Q]

i am with woogeek..... If tou are about to retired you boiler, replace it by a good not fancy woodstove, for me, wood stove is a mus as for basic exonomical heat baxk up solution ( specially if you already have a food safe flue that can accept the qood stove.

Once with a wood stove you just need a basic generator ( fridge, freezer and few lights).

But if you qant a hughes propane genset to jeat the house with the minsplit or electric resistant, that os another ball game qith more money involve....

 

[jebatty]

I too favor a wood stove as primary or backup heat. For SE PA this should easily provided needed heat, and will work especially well if you have an open concept house design. No electricity needed for heat. And for emergency backup or while you may be away, we have a cabinet-wall mount LP convection heater with a 100 gallon LP tank, millivolt thermostat -- again, no electricity needed for heat. A full LP tank will provide about 2 weeks minimum of backup heat. Then a basic generator, as mentioned, run intermittently as needed.

I understand the attraction of a HPWH. Yet, I would favor a traditional electric resistance HW heater, heat traps, super-insulated, with all hot water lines insulated. The reason being simply that by doing this we reduced our electric usage by 50% which means that in our case a HPWH would never payback in its life cycle.

Mini-split, I also agree. Depending in part on how our PV production numbers finally work out, a mini-split will be a definite consideration to replace an old wall mount AC in our living room. We're not likely to use the AC very much, but shoulder season heat would be a big plus, particularly because the mini-split qualifies for 50% reduced rate interruptible electricity. And as I continue to age (does everyone continue to age?), I can see less c/s/s wood in my future.

 

[maple1]

Do you already have propane on site?

How do you heat your DHW?

Lots of sound suggestions made already.

Tread very thoughtfully on the generator issue, and make sure you fully and accurately assess how much electricity you REALLY need to get through a power outage, and how often it really happens. Between the upfront cost, and the fuel it would use running a week straight - most people I know are way oversized in the generator department. I got a 3000w inverter generator this spring to replace a 5500/8000w Craftsman. Huge difference in fuel consumption, and I still have more than enough juice to keep my house going.

My boiler system will keep us warm using very little electricity (none if I really baby sit it). If I didn't have that, I think I would have a hard time justifying not investing in a mini-split (or two), and a good wood stove. Actually, even with it, I find myself thinking about a mini-split more & more (as age increases) for shoulder season use, reducing wood consumption (and all the work that goes with it), and some summer A/C.

I don't think I would add another fossil fuel. You could do both hot water heat & generator using the same fuel, if you wanted to. But sending my oil boiler & tank down the road was the best thing I ever did.

 

[peakbagger]

One of the problems I expect you will run into is that you are probably banking on net metering to store up surplus in one season and carry into another. Net metering is under attack in many states and if that goes away then the solar strategy changes radically.

The mini split will make a big difference as it pushes out the shoulder seasons so you don't need to start up a primary heat source. Its great on those days when its cool in the morning and warms up during the day One trade off is if you site it for optimum winter heat production, you will most likely be taking a hit on summer efficiency. Ideally for winter you want a sunny spot out of the wind. For summer you want shady with a breeze. In my area where I rarely use AC, I optimized for winter production.

I went into last winter with about 2500 kw net and intentionally used up my net over what was a record cold winter. It looks like I only have a 2000 kw and plan to use it less. I used the mini split and 3 cords of less than optimally dried wood to heat my house last winter and used very little oil (I estimate less than 50 gallons)

 

[renewablejohn]

Not long to wait for one of these

(broken link removed to http://www.inresol.se/the-genious-portable-multi-fuel-chp-stirling-generator/)

 

[dougstove]

My family was very happy to get rid of oil fired hot water and hydronic heat.
No smell, no more risk of oil spill in or out of the house.
Like others, I would be very hesitant to get embroiled in another delivery-based fossil fuel like propane.
With air sealing and insulation we heat with <3 cords of wood a year in a much colder climate.

 

[begreen]

Their website was not designed by a Genious. There appears to be no documentation, prices or specs. Ah, video says it is a 5KW continuous generator, 10KW peak, now how much fuel is consumed during this cycle and how much does it hold? Video also say "under $10K" price

 

[renewablejohn]

Their website was not designed by a Genious. There appears to be no documentation, prices or specs. Ah, video says it is a 5KW continuous generator, 10KW peak, now how much fuel is consumed during this cycle and how much does it hold? Video also say "under $10K" price

I agree website not brilliant, most details have come out through the stirling engine forum. They quote a fuel usage of 3.5kg per hour of wood pellets to produce 5kw electric.

 

[jebatty]

That's about 62,000 btu of pellet energy to produce about 17,000 btu of electric energy, about 27% efficiency, if true. Pretty close to the number for coal fired generators. Add CHP and the efficiency goes up.

 

[renewablejohn]

They actually claim 22 % electrical efficiency and 90% overall CHP efficiency

(broken link removed to http://www.inresol.se/technology/)

 

[dougstove]

Where is the chimney? Or is the stirling generator meant to go outside?

 

[renewablejohn]

Where is the chimney? Or is the stirling generator meant to go outside?

I think the generator was originally ordered as a replacement to a standard 5kw petrol generator so robust outdoor use anywhere in the world. Would not take much to modify for internal use.