Electric: Reliable distribution and backup
- Aerial
- pro: replacement aluminum wire is cheap
- pro: much easier and faster to diagnose and repair
- con: highly susceptible to damage by trees
- con: maintenance costs of tree trimming, ground clearing, pole replacement, exposed component wear
- con: risk, a fallen line to harm humans and start a forest fire
- Underground
- pro: reliability, much less likely to get damaged
- con: cost to install is ~2-3X higher
- pro: cost to maintain is much less
We currently distribute at 7,200 volts. This is very efficient and AWG #2 provides excessively adequate carrying capacity. We could distribute at 400-600V, which would require much larger (AWG #4/0) and more expensive cable.
- Choice:
- Two mid-size (15-20kVA) generators (Lodge, Tow Hut)
- Requires a building, near Tow Hut & Diesel Hut
- houses generator and transfer switch
- Requires a building, near Tow Hut & Diesel Hut
- One large (50KVA) generator
- requires disconnecting 7.2kV line from PSE, then...
- generator feeds the entire campus
- Two mid-size (15-20kVA) generators (Lodge, Tow Hut)
- We can fit a 15-20kVA generator in the generator hut
- We don't have a place for a generator near the Tow Hut
- 3Ø is better for powering rope tow motors, BEV chargers (esp. for more than one)
- If 3Ø is at 105kV, then we need a crazy expensive transformer
If terms like sectionalizer, cutout, and AAAC are nebulous, consider reading the Power Outage - Nov 2021 report. It contains much helpful content provided by Ray and Mike.
Meany is in the habit of spending a handful of thou$and$ every few years for tree pruning and maintaining a stock of aluminum power line and splices. Both bear substantial cost and risk. Another risk is having Meany's power line down in mid-winter and having zero linemen available for weeks because they're working double shifts for the utilities. This last winter our line strikes only broke a few strands.
In broad strokes, our significant power issues are:
• PSE outages • Meany line outages • Undersized generators • No backup power for tows
Our workaround right now for outages is generators. The generators are about 1/3 a solution. We have enough generator power to keep the lights on in the lodge, but not enough to run an electric kitchen or keep a vacuum cleaner from tripping us offline. No backup power for the tows is a poor experience, considering the family cost for a weekend. My envelope math thinks of a lost weekend as $3k in revenue.
We are mostly powerless when our PSE link is down, but that may not have to be the case. PSE has 3Ø lines that feed Martin Station within a power pole of our property. That line is much higher, has all the trees cleared further away, and I suspect it's far more resilient. Our current option may not be our only/best option.
It may be that our present aerial distribution is our best option and we maintain our aerial wires and try to mitigate the issues I highlighted. Bigger generator(s) sufficient to power the Lodge and Tow Hut would be such a mitigation. Another mitigation is to wait until the next tree takes down our line. Then, while the power is out and the lines are down, fell all the trees within 30' of the line. Then string the line back up. At our leisure, clear out the mess under the lines.
Looking forward 2 and 10 and 20 years, it is obvious that:
• Summers will be drier with more fires • Burning fossil fuels will get more expensive. Cost will relegate propane to backup only. • Future machines (snowmobiles, eCats) will be electric and need charging. • Clean-air regulations (now 80% smoke-free wood stoves) will get more strict. Our next Lodge stove will likely be a wood boiler with heat storage, likely augmented with electric heat pumps. Heat distribution will be the tricky/costly bit for the boiler. • Our kitchen needs a commercial dishwasher to meet health code. Heat pumps can solve a lot of cold problems for us, like keeping the kitchen / wet areas heated to 40° during the week.
PSE has the capacity we need. What we lack is redundancy/backup power. We have a variety of ways to deal with this:
• Do nothing. When the power is out, issue refunds.
- Get backup power to the Tow Hut via:
- A new generator hut near Tow Hut
- Ground-operated cutouts at pole #1-4 and feed Tow Hut via our bigger lodge area generator. • Centralized. Land power from PSE. Also house a big enough generator and transformers to power the campus.
A 600A 3Ø 208v automatic transfer switch like this one can be had for $2k, and a 45 or 50kV generator is ($5-8k). These sizes are commonly used in data centers and hospitals so there's a regular supply of gear on eBay for not-very-much money.