What influences 100% off-grid strategy and system cost
The plan is to go 100% off-grid (energy and water). What influences the strategy and cost most?
Optimising costs and making some trade-offs in an off-grid system is highly important as the initial costs can otherwise become ridiculously expensive. How to optimise the system is up to a variety of factors:
- Plot location
- House usage
- Personal preferences
- Local political and economic environment
We will give a rough idea of what influences 100% off-grid house energy systems’ prices most. This is also a summary of what to keep in mind when asking us about the different options and making decisions about a tailor made system.
Plot location and price
Weather
The most important indicator for the strategy, thus the final price is the number of hours of sunlight and rainfall.
Nature around
Shades influence solar panels’ efficiency considerably. If one of the panels in your solar array is shaded, the overall output of the system can drop by 30-40%.
Water on the plot can offer a good alternative for rainfall.
Land availability
Solar panels on rooftops are more expensive and typically not ideally placed in terms of the sun.
Furthermore, rooftop surface is limited.
House usage and price
Usage
The off-grid system should be built according to usage, with an option to grow in the future, if necessary.
Back-up Energy
The cost of the back-up system can vary considerably.
Large battery banks are expensive. Generators’ and tanks’ prices also vary in thousands (up to €15,000)
Seasonality
Solar panels overproduce during the summer. How much is the house in use during the winter?
Back-up systems are engineered based on “what ifs”.
Personal preferences and price
Choices
There is a wide range of gadgets available, but their price tags are different. E.g. Lithium-ion batteries have almost double the price of lead–acid batteries.
Life style
Are you willing to take 2 minute showers instead of 15 minute ones? Are you willing to cook on wood charcoal that is left after furnace heating?
Appliences
Smart appliances can influence energy consumption. E.g. a smart water boiler can save up to 50% of back-up energy, warming up the water when the sun does shine and optimising it’s overall usage.
Political and economic environment
Local legislation
Perhaps cutting trees around the house is illegal and trees shade solar panels?
Is there a river next to the plot and hydropower is an option?
It can happen the the “cheapest” option is impossible to implement or not that cheap after all.
External policies
Power-generating pellet boiler sound like an option? Perhaps now, but there are serious debates in the EU around whether pellet heating is sustainable. The same with diesel. When the cost of these fuels goes up, it might make sense to invest into a more “sure thing”.
Future proofing
The off-grid system should be built in a way that it could also be changed. For example, if you are not sure how much back-up power you need, start smaller, but make sure that the general system could handle a future expansion.
What are the most expensive decisions?
Energy saving
Lithium-ion batteries cost roughly double the price of lead-acid batteries, but are cheaper in the long term. Hydrogen is very expensive at the moment – would you bet on it now or in 10 years?
Back-up generator
Pellet and diesel generators are considerably cheaper, but perhaps not that cheap in the long term.
Roof vs land
Roof integrated solar panels look nice, but if there is available land in direct sunlight, it certainly makes sense to use the land as the panels can be installed to have the highest possible production efficiency (direction as well as the angle).