Solar-Diesel Power Generation primarily uses solar power, supplemented by diesel power, to supply electricity to the load and store excess energy in batteries. It has significant advantages in providing stable and continuous power.
1. Application Scenarios
In island areas or far country-side, where the electricity grid coverage is insufficient or unstable, diesel generators are often used for power generation. Due to the remoteness of these conditions, if a generator breaks down, it is difficult to repair it promptly, which is a big trouble for daily life and work.
Otherwise, the noise and pollution from diesel generators cannot be easily mitigated.
Diesel power generation is often unstable, sometimes not friendly to the load. Pure solar power generation also struggles to meet actual load demands.
The complementary solar-diesel system features automatic voltage regulation, improving power quality. When solar power generation is insufficient, it switches to the diesel generator to ensure continuous power supply.
Desert Solar-Diesel Hybrid Power Generation System
Desert Solar-Diesel Complementary Power System
Thus, complementary solar-diesel systems are an excellent solution to the aforementioned issues. Hybrid power stations also help reduce carbon dioxide emissions and lower power generation costs.
2. Cost Comparison per Kilowatt-hour
Diesel power generation is relatively expensive. Typically, diesel generators have a conversion efficiency of about 31%. For example, a Cummins 50kW generator consumes 216g/kW. Using the current price of 0# diesel at 7.6 yuan per liter, the cost per kilowatt-hour is approximately 1.6 yuan. In contrast, the cost of solar power generation is around 0.5 yuan per kilowatt-hour.
Additionally, diesel fuel prices are continually rising. Maintenance of solar power generation is simpler and less costly compared to diesel generators. Furthermore, solar power has significant advantages in reducing carbon emissions compared to diesel generators.
Complementary Solar-Diesel Diagram
3. Case Study: Complementary Solar-Diesel Project
Example: Deye’s 500kW Solar-Diesel Hybrid Project at Nepal Pharmaceutical University.
The project uses DEIF’s fully automated sustainable energy controller (ASC) to achieve reliable, fully integrated optimization between sustainable energy devices and generator sets.
ASC is fully compatible with DEIF’s power management system technology, featuring modular design with scalability and flexibility, supporting various operational modes including off-grid, grid-tied, and hybrid modes. It features grid-compliant breaker control, rapid shutdown of sustainable power sources, directional power protection, and grid outage protection. The ASC-4 solar controller plus DEIF diesel generator controller can manage power effectively.
4. Power Station Control Logic
- In case of a power outage or off-grid condition, the diesel generator simulates grid conditions, allowing grid-tied inverters to operate.
The power station requires at least one diesel generator to be online, with a minimum load setting for the diesel generator.
If the load is less than the solar capacity:
One diesel generator operates at the minimum load setting, with the excess load supplied by solar power. If the load is less than the diesel generator’s minimum load setting, the load is fully handled by the diesel generator.
If the load equals the solar capacity:
One diesel generator operates at the minimum load setting, with the excess load supplied by solar power.
If the load exceeds the solar capacity:
One diesel generator operates at the minimum load setting, with the remaining power supplied by solar. If the load exceeds the combined capacity of solar and one diesel generator, the excess load is handled by the diesel generator, which adjusts based on load size.
- When the load suddenly changes, the diesel generator responds first, and the system adjusts via controller communication.
5. Advantages of the Solution
A hybrid solar power system allows for better utilization of renewable energy.
Independent renewable energy systems are typically designed for worst-case scenarios due to their variability and instability. Therefore, these systems must be designed for periods of minimal energy production. Consequently, during peak solar periods, excess energy may be wasted, reducing overall system efficiency. If the worst month differs significantly from others, wasted energy can equal or exceed the designed load demand.
Solar-Diesel hybrid system Recommendation
- Deye Inverter: Deye hybrid inverter connect to diesel generator perfectly, you can easily setup your Solar-Diesel system with Deye inverter
- Cummins Diesel Generator: Cummins diesel generator is the top brands in the power generator field, their after-services over the world
High system practicality.
In independent systems, the variability and instability of renewable energy can lead to unmet load demands. A hybrid system significantly reduces the incidence of load power shortages.
Compared to diesel-only systems, hybrid systems require less maintenance and use less fuel.
Higher fuel efficiency.
At low loads, diesel engines have low fuel efficiency, leading to waste. A hybrid system can control the diesel engine to operate near its rated power, improving fuel efficiency.
Better load matching flexibility.
With a solar-diesel hybrid system, diesel generators can provide instant large power, making the system suitable for a broader range of loads, such as large AC loads and surge loads. It better matches load and power generation, easily handling peak load periods with backup energy. Sometimes, the load size necessitates a hybrid system, as large loads require high current and voltage, which would be costly with solar power alone.