Solar + back-up system cost
Background
The cost for an off-grid energy system can vary widely depending on several factors such as the size of the system, location, quality of components, back-up energy choice, installation costs, and any additional features or requirements that come with the plot.
We wrote a general article about “What influences 100% off-grid strategy and system cost” and will now focus on ENERGY in more detail based on our ODYL House example.
We get many enquiries about the off-grid system where we need to say "DEPENDS A LOT". The below examples are based on a 15kW solar system + 30kW storage + 20kW back-up system for the long and dark winters.
Solar Panels
Prices vary depending on the brand, type (monocrystalline, polycrystalline, or thin-film), efficiency, and capacity. On average, solar panels + mounting hardware can range from €0.5 to €1.5 per watt. For example, a 15 kW solar panel system would most likely cost between €7,500 to €20,000 for the panels, mounting and cables/wiring.
Panels
The panel itself can cost around €0.1 per watt, ordering from China. BUT, logistical costs, ordering small amounts (which they are not that interested in) would most likely triple the cost. And then you are left with all the warranty questions and end up buying from the local whole-seller.
Mounting hardware and wiring
Racks, rails, and clamps are used to attach the panels to the roof or ground-mounted structure. Cables, and wiring are essential components of a solar system. The cost will depend on the size and complexity for installation.
Batteries and back-up power
Off-grid systems require battery storage to store excess energy generated during the day for use at night or during periods of low sunlight. Battery costs depend on the type (lead-acid, lithium-ion, low voltage vs high voltage etc.) and capacity needed.
Battery size
Off-grid systems require more than just “one night” savings and worst case/optimal scenario needs to be agreed. The cost of a 30kWh battery bank can on average vary between €7,000 (low voltage) – €25,000 (high voltage).
Back-up power
Backup Generators: Diesel, propane, or gasoline generators are popular backup power options. They can provide reliable power during extended periods of low solar generation or when batteries are depleted. Backup generators should be automated to start automatically when battery voltage drops below a certain threshold, ensuring seamless transition to backup power. The price for back-up generators and necessary infrastructure for approx. 20kW back-up generators can vary between €6000 – €20,000.
Extra technology needed
Inverters and charge controllers (+ monitoring) can be combined into a single product, known as an “inverter-charger” or “hybrid inverter.” Inverters and battery banks can also be combined into one device.
Charge controller
Charge controllers regulate the flow of electricity from the solar panels to the batteries, preventing overcharging or damage. The cost depends on the type (PWM or MPPT), capacity, and features. MPPT charge controllers tend to be more expensive than PWM controllers due to their advanced technology and higher efficiency. The cost for a charge controller can range from €100 to €500 or more.
It is most likely already integrated with the inverter!
Inverter
Off-grid inverters convert the DC electricity from the solar panels and batteries into AC electricity suitable for household appliances. Inverter costs vary depending on size, type. Three-phase inverters tend to be more expensive than single-phase inverters due to their higher power capacity and complexity. However, they offer greater efficiency and performance. Prices for e.g. 20kW hybrid inverters with a charge controller and monitoring options typically range from €2000 to €5000.
Monitoring
A monitoring system allows you to track the performance of your solar panel system, monitor energy production, and identify any issues or maintenance needs. Some solar panel systems come with built-in monitoring capabilities, while others require the installation of a separate monitoring system. It might be subscription based. Let’s assume monitoring is integrated for an off-grid system and the cost would be €0.
The human factor + plot location specifics
Labor costs typically make up a significant portion of the total installation cost and may range from €2,000 to €10,000 or more for a 12 kW solar + possible back-up system.
Installation + logistcs
While some people may opt for a do-it-yourself (DIY) approach to solar panel installation + everything else, it’s generally recommended not to do it.
The cost for installation depends on the solution and size of the system. For the example given above (panels, back-up, storage, cabling etc.) would vary between €1500 – €4000.
Permits
Before installing solar panels, you might need to obtain the necessary permits and approvals from local authorities (e.g. for using gas tanks or even installing solar panels).
Plot/location preparation
Dependent on the final off-grid strategy, the plot might need extra works. In addition, all the technology might require it’s own “building” where everything is stored and logistics also takes its share The cost for extra plot works can vary from €0 (roof panels) to €5000.
Summary
- If the sun is shining 365 days a year, back-up generators might not even be necessary and PV panels + battery storage would be enough (perhaps a fire-place – just in case?)
- If the winters are long and cold, a larger back-up system is a necessity.
One also needs to consider efficiencies for technology chosen and worst case scenarios – the technical capabilities of devices are never 100% of the “name of the product”. Always think “worst case scenario” or “possible future scenario” and plan accordingly. Extra solar panels, extra storage can always be added – no need to over-dimension systems, but make sure the created infrastructure could supply for those possible future scenarios.
The final price always depends on the requirements/preferences and can vary enormously. Our price offers for the 100% off-grid energy solution have varied from €10,000 (smaller systems) to €30,000.