Building to be independent of an unreliable grid.
- Brian Boschen
- Single-Family Residence
- St. Croix, VI 00820
- 1,670 sq ft
- Energy need met:
- 100% or more of electricity
- Passive house
- Zero net energy
- Solar PV
- September 2018
- Size of System:
- 7.2 kW
- To generate electricity
- Gross Cost of System:
- Value of Tax Credits:
- Net Cost of System:
- Annual Savings:
- Own or Lease:
- Purchase with Loan
- Additional Financial Notes:
- Financed as part of house construction. Further savings anticipated by installing an electric car charging station and reducing gasoline costs by $120 per month.
- Tesla Energy
- ProSolar Systems, LLC (St. Thomas)
24 x Trina TSM-300W panels 2 x Tesla Powerwall 2.0 Tesla Powerwall: Energy Gateway
Independence from fragile grid which fails weekly, and which was down for 3+ months after last years hurricanes. Powering Air Conditioning! Providing charging for an electric car, saving gas even with the use of A/C! Web monitoring of power generation and usage via smartphone app
Performance monitored by supplier
Efficiency or Sustainability Improvements:
Quad-Lock Insulated Concrete Forms (ICF) construction provides 2" of foam insullation inside and out on 6" poured concrete exterior walls, and 7" of steel reinforced foam insulation under the poured concrete roof. Heat pump water heater, high efficiency mini-split air conditioning in bedrooms. Intelaflo multispeed high efficiency pool pump. Glass blocks for ambient lighting. LED lights throughout. Energy Star appliances. High efficiency ceiling fans.
We were without power for over 3 months following hurricanes Irma and Maria. Since water is pumped from cisterns, we were also without water. Aside from that, the utility regularly has outages on a weekly basis, and locally gas generated costs are very high, ranging from $0.45-0.60/kWh. We wanted to be free to use air conditioning when needed, power our swimming pool pump daily, and drive without concern for fuel economy.
We initially specified low cost FLA batteries for storage, recognizing that storage costs are coming down. However, we didn't anticipate that they were coming down as quickly as they did, and we switched to Tesla PowerWall 2.0 before installation - at a lower cost!
Experience with Installer:
We leveraged the local experience of other friends who had already installed net-metered or grid-tied systems and their experience with local installers, and decided to go with a well known major local installer.
We were originally going to do net-metering. The day we went to sign the contract, the local utility reached their net-metering capacity cap, preventing us from signing up! Meanwhile, we had friends who had recently installed net-metered systems, and when the grid went down for 3 months due to hurricane damage, our friends with net-metering were without power unless they ran their generator. That sealed our decision to go completely off-grid!
Single-Family Residence|Solar PV