Strengthening Albania’s energy security

Embracing hydropower

The dual challenges of climate change and energy crisis are focusing minds on renewable power production and energy self-sufficiency.

For many nations around the world the subject of that focus is primarily on the provision of solar photovoltaics and wind turbines. But for others, where conditions allow, hydropower is a viable option.

Albania is one such fortunate nation. Boasting a diverse climate from low lying Mediterranean to high alpine climates, a mean annual precipitation of as much as 3000mm in some areas and a diverse geography of coastal plain to the mountainous Albanian Alps, it offers every opportunity for renewable energy.

Hydropower is one area where Albania has embraced that opportunity. As much as 95% of its total renewable energy production is delivered by hydroelectric-power projects.

95% of renewable generation in Albania is hydropower

40% of Albanian energy is renewable

But even with renewables accounting for around 40% of its total electricity use, the country is still dependent on imported power.

Now plans are in place for progressing with a front end engineering design (FEED) for a hydropower project at Skavica in the Drin Valley that will support making a business case for the project to help reduce that dependence, increase the amount of energy from renewable sources and protect the country’s existing system from the vagaries of the weather, particularly reduced rainfall due to climate change.

Location map

A Mott MacDonald team is providing design and engineering services for the development of the preferred configuration and FEED for the Skavica hydropower project, including a technical topographic, geological and hydrological study, the preparation of a preferred option report and design FEED for our client Bechtel and Albanian national power company Korporata Elektroenergjitike Shqiptare (KESH).

Key project aims

While Albania is committed to attaining its energy independence, a high proportion of its renewable generation is based around hydropower output that is affected by fluctuating hydro-meteorological conditions.

The Skavica Hydropower Project is expected to improve Albania’s national power security – not just by increasing generating capacity through the construction of a new dam and powerhouse but also by boosting the output of existing downstream hydropower power plants (HPPs) that form the Drin River cascade by better regulation of the water storage available in the reservoirs downstream.

300,000m³ of flood storage to protect local people

75km from the Albanian capital, Tirana

200MW of extra power provided

Management of this cascade can become difficult during times of heavy rainfall and snow melt, leading to increased potential for flooding. The Skavica HPP will improve the control needed to help reduce the frequency and severity of these events by providing flood storage of the order of 300,000m³ at Skavica dam, protecting inhabitants and property.

Located on the Drin River about 75km from Albania’s capital city Tirana, the proposed Skavica HPP is expected to be the uppermost plant that forms the Drin River cascade – an arrangement of several hydropower projects along the river’s route. National power company KESH is addressing those issues and has called in our client Bechtel to deliver the proposed Skavica hydropower project with a potential of the order of 200MW.

​Cascade projects downstream of the proposed Skavica hydropower plant

Photogrammetry to the fore

With its steep sides and typical karstic terrain, the Drin River gorge at Skavica has seen our team embrace use of cutting-edge technology to develop the design for the hydro power project (HPP) – and reduce exposure to dangerous environments.

Featuring heavily vegetated and fissured slopes at angles greater than 75 degrees in places, the site investigation was set to prove difficult. Normally roped access methods would be used to carry out surveys but, in a move to reduce exposure to such challenging working conditions, speed the survey process and provide accurate models of the gorge that can be interrogated from the safety of the office, the team looked toward remotely controlled drones.

3D model of the gorge

These drones were used to take thousands of overlapping high-resolution images that could then be used to build up a 3D model of the gorge at the dam’s proposed locations. These models could subsequently be interrogated to extract rock mass information required for design. An initial ‘wide survey’ was used to selected areas of interest for more detailed surveys. The system was even used to survey existing adits – cut into the rock during work in the early 1980s – to ascertain they were clear of blockages, rockfalls and even bears.

The quantity of information collected through photogrammetry in this early phase of data collection has reduced workforce exposure to safety hazards. Moreover, the photogrammetry models have allowed a more complete overview of the karst features and rock mass structure at inaccessible gorge sides, which reduces uncertainty in subsequent design.

It has helped reduce design uncertainty and also reduce the workforce’s exposure to danger.

Ed Russell

Principal geologist

The models provide an added benefit that the same areas can be revisited again during design development if additional information is required, something that would not be possible if data collection had been manual.

“Photogrammetry has become a valuable addition to our arsenal. Using these new techniques has allowed us as engineers to be better informed. It has helped reduce design uncertainty and also reduce the workforce’s exposure to danger,” says principal geologist Ed Russell.

Our power and energy model proves its worth

Renewable, clean electricity production is often hampered by the vagaries of the weather. If the sun doesn’t shine, the wind doesn’t blow, or it doesn’t rain, renewable electricity generation is impacted.

For hydropower projects the risk is based around the flow of water that feeds into the project which varies from season to season and the potential output of any installation will vary similarly. This hydrological risk is an important factor in the development of any HPP project. Drawing on our experience and expertise in hydrology we’ve supported our client on how to make best use of the available water.

One especially challenging aspect at Skavica is the multifunctional use of the reservoir, balancing the operational requirements of both flood protection and energy production, as well as assessing the impact on the cascade of hydro projects downstream. To investigate these different operating requirements and impacts, our designers used our ‘hydropower energy model’ (HPE) to represent every part of the cascade. The model estimates how much energy the projects can produce based on the amount of water available to each.

Our hydropower energy model was developed in-house and is continuously being developed and adapted for increasingly complex projects such as Skavica HPP.

It enables our engineers to test different designs and operational configurations to assess the balance between energy production and flood prevention and highlighting the potential benefit this project can provide to the whole cascade, while assessing the potential impact of climate change. We were also able to take into account the effect that daily and seasonal electricity price variances will have on the revenue it produces for KESH.

“For the design optimisation and climate change modelling we modelled nearly 500 different scenarios,” says technical director Jake Spooner. “This allowed us to look at a greater number of detailed scenarios and use the HPE model to help us develop the design.”

Weighing the options

The complex hydrological overview of the Skavica project site has considered precipitation, the effect of climate change on evapotranspiration, river flows and flood flows throughout the Drin River’s wide catchment area.

This is an extremely demanding project technically. The seismic, geological and hydrological conditions have made it one of the most challenging of my career.

Philip Harvey

Project manager

The ramifications of these complexities aren’t lost on project manager Phillip Harvey. “This is an extremely demanding project technically. The seismic, geological and hydrological conditions have made it one of the most challenging of my career,” he says.

These technical challenges have influenced the options available to the design team and the recommendations it has been able to make.

With the gorge characterised by fissured limestone on both banks, and a shallow depth of alluvium at the riverbed, the site is conducive to a variety of types of dams.

162m - height of dam proposed

But with steep valley sides ensuring the dam section could vary hugely across short transverse distances all the indicators pointed toward a rigid dam rather than embankment dam.

We anticipate the final design will be a roller compacted concrete (RCC) gravity type with a height up to 162m, a spillway for overtopping water and a headrace tunnel delivering water to the powerhouse and turbines.

We studied various options for the final layout and location of the HPP at the three potential axes across the gorge.

The five possibilities

Option 1A – locates the dam on the upper axis where the gorge is particularly narrow and steep sided and surface/underground powerhouse with headrace on the right bank.

Option 1B – this is the same as 1A in relation to the dam but features a surface powerhouse with different length headrace tunnel.

Option 1C – also features the same dam location as 1A but differs in relation to the headrace route and powerhouse location, utilising the left side of the valley.

Option 2 – uses the central section of the gorge with the dam sited on the middle axis and features a surface powerhouse with headrace tunnel on the right-hand bank.

Option 3 – sites the dam on the lower axis at the downstream end of the gorge where it is narrower than the middle reaches and features a surface powerhouse with headrace tunnel on the right bank.

Option 2 – dam on middle axis with headrace tunnel on right bank

With all the technical data at our fingertips and a clear view of the factors that would variously affect the design, we recommended that options 1B and 2 should be taken forward to the next stage of the project.

Of these we favoured option 2 through a comparative review of project risk. We noted that while Option 1B featured a more efficient upstream dam axis, it also required a longer headrace tunnel and featured greater project uncertainty.

But we are certain either choice will provide an important addition to Albania’s renewables’ capacity, helping to reduce the country’s reliance on imported energy.

Digital modelling benefits

With such a rich vein of information available to the project team it is perhaps unsurprising that our client Bechtel requires us to be fully BIM compliant during the project development phase.

Data accrued during the project’s initial survey and optioneering phase can enable and improve the asset’s future efficient operation. Ultimate client KESH sees the project’s BIM models as an effective tool to monitor and maintain the asset.

“It is one of the key requirements of our work on Skavica HPP. Bechtel has requested it specifically as part of our delivery,” says our project principal Ajay Chaudhary.