Micro Hydro Power Station Or Solar Panel Arrays?

When it comes to reliably generating enough green energy to power your organization, the advantages of micro hydro power stations over solar panel arrays are clear. As long as your location has a viable river, small hydro plants have major benefits when it comes to reliability, size and return on investment. Thanks to Turbulent revolutionary water turbines, small rivers with less water flow across the globe can now be harnessed to provide locally-produced reliable and green energy.

The key to this is the high plant factor of micro hydro power stations.

What is Plant Factor?

Plant factor —also known as capacity factor, is the ratio of a power plant’s average produced energy to its installed capacity. In other words, it shows the relationship between how much power a plant could technically produce and the amount it actually generates.

• A Turbulent micro hydro power station has a plant factor of up to 90%. That means that on average throughout the year, the turbine provides almost its full capacity for power generation.
  

• In comparison, the average solar panel array has a plant factor of 18%. As a result, throughout the year a solar panel array generates less than a quarter of the power it is capable of.
  

Since solar panels depend on the sun, they only operate at peak performance for a few hours a day, and produce no power at all at night. Furthermore, their power generation is also affected by weather, with production reducing dramatically from something as simple as a cloudy day. They also require constant maintenance throughout the year to adjust their angle to the sun.

Meanwhile, rivers flow constantly day and night, enabling water turbines to generate a steady, reliable supply of electricity 24/7. While water levels can vary throughout the year, the variation in production is much easier to predict.

This is a huge contrast in terms of efficiency that impacts organizations seeking clean energy in several key areas:

Continuous Power

Micro hydro power stations generate continuous energy, and solar power does not.

What does that mean for businesses and communities relying on these energy sources?

To start with the obvious, a solar panel array is going to need batteries if it is going to keep the lights on for more than a few hours a day. Batteries are expensive, take up yet more space, and require specialists to maintain and repair them. Even with diligent maintenance and repair, they have a limited lifespan and like the solar panels themselves, batteries lose efficiency over time.

While a micro hydro power station could include a battery to store excess power, lots of energy storage capacity is unnecessary since the water turbine generates a steady supply of power with no downtime.

Continuous power generation is a major benefit of small hydro power, especially at off-the-grid sites. According to the Asian Development Bank, the use of small hydro power to provide local off-the-grid power will be key to achieving Viet Nam’s goal of 100% rural electrification by 2025.

Scale

Plant factor also has a big influence on the size a power plant needs to be. Micro hydro power stations, as the name suggests, enables the use of water turbines at small sites without taking up much space. Thanks to the high plant factor, large amounts of redundant power generation capacity are not needed. A 200 kW vortex turbine is only about seven metres across.

In contrast, solar panel arrays require huge amounts of land to be cleared. To generate enough power outside of peak conditions, a lot of additional capacity is needed. To match the practical performance of a 200 kW water turbine, a solar panel would need to be capable of generating up to 2,000 kWp.

As a result, a solar panel array capable of providing 200 kW of continuous power takes up 15,000 square metres of land, without taking the batteries into account. That is the same as three football fields of space! A 200 kW water turbine would fit into the centre circle of a football field with space left over. This is one of the reasons the United Nations Industrial Development Organization (UNIDO) is focusing on small hydro power in rural communities as a cost-effective energy solution with minimal or no environmental impact.

Returns on Investment

How long does it take for a power plant to pay for itself?

A micro hydro power station producing 200 kW of continuous power costs around €800,000, or €4,000 per kilowatt.

Solar power costs around €2,000 per kilowatt. This may seem cheaper, but to produce 200 kW of continuous power, a solar array would need a capacity of up to 2,000 kWp. That means a solar panel array with equal output to a 200 kW water turbine would cost €2.4 million.

This figure does not include the cost of batteries, the large amount of land needed or maintenance costs. It is worth remembering that these also add to the cost of solar power, and micro hydro power stations require very little maintenance and repairs by comparison.

The performance of water turbines does not degrade over time, while solar panels and batteries have limited lifespans. A solar panel can lose as much as 1% of its power production capability over the course of a year.

With a 90% plant factor, a 200 kW water turbine would produce 1,576,800 kilowatt-hours per year. Assuming a plant factor of 15%, a 200 kW solar panel array only produces 262,800 kilowatt-hours a year. This adds up to 47,034,000 kWh over a lifespan of 30 years for micro hydro power stations, and 7,884,000 ‬kWh for solar power.

Levelized Cost of Energy

Levelized Cost of Energy, or LCOE, shows the cost of each kilowatt a plant produces in an hour over the plant’s lifespan. Calculating LCOE is simple – just divide the net cost of the plant by the kilowatt-hours it produces in a year.

In other words, an €800,000 micro hydro power station produces 200 kW of continuous power at a cost of less than €0.02 per kilowatt. An equivalent solar array requires a much greater initial cost of at least €2.4 million, with a Levelized Cost of Energy —in the very best case, of €0.03. According to the International Renewable Energy Agency (IRENA), this means small hydropower is typically the cheapest energy solution in developing countries.

Buying power from an energy supplier costs businesses worldwide an average of $0.12 (€0.11) per kilowatt-hour. A 200 kW water turbine produces more than 47 million kilowatt-hours over a 30 year period. This much energy would cost €5.17 million at current prices. That is a yearly saving of over €143,000!

Businesses could save more than €4.3 million over the course of 30 years by investing just €800,000 in a micro hydro power station. In contrast, spending €2.4 million on a solar panel array would save €2.7 million over the same time span, a yearly saving of €90,000.

This makes micro hydro power stations 37% more cost-effective than solar power over a 30 year period.

Payback

Through savings on energy costs alone, an €800,000 micro hydro power station would pay for itself in less than 6 years. At a yearly saving of €90,000 a solar panel array with equal output could take as long as 26 years to pay back its €2.4 million cost.

In the same timeframe, a water turbine will have made more than triple its initial cost in profit!

Profit

Excess power you generate can be fed into national grids for profit via Feed-In Tariffs or Power Purchase Agreements. This enables businesses to pay back their investment costs even faster, and maximize profits. Many countries, such as the UK, will pay businesses and individuals for renewable energy exported to the grid. On average, this system enables green energy to be sold to the grid at an average price of €0.1 per kilowatt-hour.

This is much more beneficial to micro hydro power stations than solar arrays. Water turbines generate power constantly, meaning that outside of peak energy usage times such as work hours, more power is being generated than is needed. In contrast, due to their limited peak performance hours, ‘excess’ power needs to be stored for off-peak performance and night time.

And the winner is...

The choice between micro hydro power stations and solar panel arrays is a no-brainer. If a viable river is available, micro hydro power takes up much less space, has much lower setup costs, pays for itself in just a few years, it will produce more energy for the same installed capacity of a solar plant and is a lot easier to maintain.

Watch the case study video below of our latest installations in the Balinese jungle.