(Credit: iStock)

How solar may save Ukraine's nuclear wasteland

The Ukrainian government wants to turn part of the Chernobyl Exclusion Zone into a solar farm. Could the site of the world's worst nuclear accident get a new lease of life?

In April 1986, the Chernobyl Nuclear Power Plant suffered a catastrophic meltdown. The resulting explosion released some of the reactor core into the atmosphere, creating the worst nuclear accident in history. The subsequent radioactive fallout – some of which fell as far as Wales – resulted in the Exclusion Zone being formed around Chernobyl.

The Chernobyl Exclusion Zone today covers an area of 1,000 square miles (2,600 sq km), including an area that was once home to 120,000 people, most of whom lived in the now abandoned cities of Pripyat and Chernobyl. The Exclusion Zone remains in effect, as the area is considered too contaminated for residential or agricultural use.

Despite the meltdown in Reactor 4, Reactors 1-3 of the Chernobyl Nuclear Power Plant continued to be operated, because Ukraine needed the energy. Reactor 3 was only decommissioned in December 2000. 

Apart from a handful of radiation hot-spots, the Chernobyl Exclusion Zone has become a comparatively safe area to visit, as long as you’re staying for only a short time. Due to significant interest in the area, as well as the unique biodiversity there, the Chernobyl Exclusion Zone was officially declared a tourist attraction in 2011. And with the successful installation of the new sarcophagus, which will seal in the damaged reactor for 100 years, the disaster site is about to see renewed activity.

Earlier this year Ostap Semerak, the minister for ecology and natural resources in Ukraine, announced plans to build a large-scale solar farm in Chernobyl’s Exclusion Zone. “The first phase will install solar panels with a total capacity of one gigawatt,” says a ministry spokesperson. “In the future [there] are plans for capacity increase.”

A large field of 25 acres, filled with solar panels, generates approximately 5MW. To put this into perspective, the football pitch at Manchester United’s Old Trafford ground is 1.75 acres and would only generate 0.35MW. So, for a solar farm to generate a gigawatt of power, it will need an area of 5,000 acres, which is nearly eight square miles. There is, fortunately, a lot of available land in the Exclusion Zone.

Solar panels are relatively complex in their manufacture but are relatively simple in their form and resistance to interference or deterioration – Alan Thomson, Arup

The idea of building a solar farm in the Exclusion Zone has merit. “The decision is based on the presence of a network of electric power lines, which are hardly loaded, and their proximity makes it possible to connect to the power grid at minimal cost,” says a spokesperson from the ministry. Along with the existing high-voltage infrastructure, there is an existing population trained in power plant operation, and the area can’t be used for agriculture because of the residual fallout.

Solar panels generate electricity from the Sun’s photons, storing electrons within a top layer of silicon that then flow to another silicon layer on the bottom, generating an electric current.

“Solar panels are relatively complex in their manufacture but are relatively simple in their form and resistance to interference or deterioration,” says Alan Thomson, the global head of energy for Arup. This makes solar panels ideal for power generation in remote or hard-to-reach areas.

There are over 40 different types of solar panel technology available, and whilst they operate in effectively the same way, some are more efficient. In cases such as the Exclusion Zone, where there is lots of space, the Ukrainian government will most likely be seeking cost-effective methods for using the most durable types of solar panel technology. The exact solution will be determined once the feasibility study is completed.

The Chernobyl Exclusion Zone lies on approximately the same latitude as southern England. This location offers excellent solar power generation during the summer months, but less so during winter.

Building a solar farm capable of generating 1GW in the Exclusion Zone will present a series of engineering challenges, however.

The first key point will be determining where exactly to build the solar farm. There are various points that will need to be considered, the primary issue being the need to avoid any radiation hot spots.

These radiation hot spots are already quite reliably mapped out. Although solar panels will not be affected, there is always the possibility that workers could be exposed to high radiation levels during installation or subsequent maintenance, either onsite or travelling within the zone.

Another issue will be keeping the solar panels clean so they work as efficiently as possible

Since radioactive isotopes from the Chernobyl accident have now seeped into the soil, engineers must avoid disturbing the ground as much as they can. “Screw-piles, which are giant corkscrews which provide the foundation, rather than digging a hole for a big lump of concrete” could be one way to install the panels without disturbing too much soil, says Thomson.

Another issue will be keeping the solar panels clean so they work as efficiently as possible. Given the environment, solar panels will need to be installed at a 30-degree angle so they can shed snow, which will also have a cleaning effect as it slides off. Many solar panels also use special coatings that make dust collection less of an issue than it was in the past.

The solar farm will also need a transformer to “step-up” the electrical output from the farm to the 750V used by the Ukrainian energy grid.  “The output from the nuclear power plant would not be comparable to the solar panels,” says Thomson. “You will need to put in some form of substation to step-up transforming capability.” However, building a new substation may involve digging foundations, which could then potentially disturb the ground contaminants.

There would also be environmental considerations, as there has been significant interest in the area’s biodiversity as it recovers from the 1986 accident. Since the disaster, when tens of thousands of residents were evacuated, the Exclusion Zone has become a haven for wildlife.  Existing animal populations have flourished and some rare species, such as Przewalski's horses, have returned. “You would want to be careful to not be encountering environmental objections because you are interfering with something that people did not want in the first place, but they are quite interested now that it is there,” says Thomson.

One of the key advantages of solar farms is that they can be monitored remotely, meaning the on-site personnel will not be required to perform inspections. Solar panels can be checked off-site to assess their performance.

The Exclusion Zone could resurface, 30 years after the accident, [to] become the centre of the Ukrainian energy sector – Ukraine’s Ministry for Ecology and Natural Resources

Once a certain number of solar panels need to be replaced, a maintenance team can be sent with precise details of which panels are to be replaced and where they can be found, minimising their time spent in the Exclusion Zone.

One of the greatest problems of solar panels is that they only generate energy during the day, which is naturally far less during the winter months. This could be offset by storing any excess energy generated during the day. One such way this could be achieved is through using the pump storage hydro scheme located in the nearby city of Dniester, which is expected to be finished in 2017.

Pump storage hydro is used to store energy using the gravitational potential energy of water. Excess energy within the grid is used to pump water into the upper reservoir. During periods of high demand, the stored water is released, powering turbines to produce hydro-electric power.

Looking to the future, it would not be surprising if other forms of renewable energy are employed. “The implementation of solar energy projects is one of the development priorities of the Exclusion Zone,” says the ministry’s spokesperson, “but not excluding other forms if they are attractive to investors, [such as] wind power and biofuels.”

“At some stage, they will want to look at a mix, in terms of getting that diversity,” says Thomson.  “Wind farms can generate electricity when solar farms cannot, such as night.” However, wind farms present their own problems, most notably the invasive foundations which need to be built – a no-go in the radioactive Exclusion Zone.

The Ukrainian government is currently at the “pre-study and preparation phase”, and are in talks with investment firms and energy developers in order to secure financing.

“The Exclusion Zone could resurface, 30 years after the accident, [to] become the centre of the Ukrainian energy sector,” says the ministry’s spokesperson.

With the development of this colossal solar farm, Chernobyl will reclaim its place as the foundation for Ukraine’s energy supply – but this time in a safer and more environmentally-conscious form.

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