VILNIUS, Dec 21 (AFP) - In Lithuania, a giant, disused electrical transformer built in 1980 in present-day Ukraine has been dusted off and prepared for shipment. It will travel by sea to Romania and then back to Ukraine, possibly in the coming weeks.

Rokas Masiulis, head of Lithuania's power grid, said his company was searching warehouses for anything else Ukraine might need to repair the damage done to its electricity system by repeated Russian missile attacks.

"The Ukrainians say they are fine to receive anything, including things that are not working or broken, as they can fix the equipment themselves," he told Reuters.

While the West rushes to replenish Kyiv's stocks of arms and ammunition, countries in Europe and beyond are also in a race to supply transformers, switches and cables as well as diesel generators needed to light and heat the country in winter.

Ukraine has shared a list with European countries of some 10,000 items it urgently needs to maintain power.

Former members of the Soviet Union and the ex-Communist bloc have a major part to play based on their proximity and that some grids in the region still have hardware compatible with Ukraine's.

Masiulis said the greatest need was for auto-transformers, like the one destined for Ukraine. Worth around 2 million euros ($2.13 million), it weighs nearly 200 tonnes and took two weeks to be stripped of removable parts and drained of oil for transport.

"We are in the process of updating our grid, and everything we strip down we send to Ukraine," he said. Latvia, Lithuania's northern neighbour and also once part of the Soviet Union, said it was sending five large transformers to Ukraine, two of which were ready move soon.

Since early October, Russian forces have targeted Ukraine's energy infrastructure, causing blackouts and forcing millions of people to endure sub-zero temperatures with little or no heating.

Moscow says the strikes are justified as part of its "special military operation" to degrade Ukrainian forces. Kyiv and the West see the barrage as a cynical attack on civilians to break their spirit and weaken the enemy.

Regional European bodies and countries including Azerbaijan, France, Latvia, Lithuania and Poland and individual companies have already sent thousands of pieces of equipment to Ukraine.

"We are searching all over the world for replacements of the equipment destroyed during the attacks," Yaroslav Demchenkov, Ukraine's deputy energy minister, said in early December.

Ukraine had managed to avoid a "total collapse" of the power distribution system, he said, but disruptions are significant. Some 80% of Kyiv region was without electricity for two days this week after Russian missile and drone attacks.

Estimating the total value of the support is impossible, given the fragmented and hurried nature of the response, but transformers and generators worth tens, if not hundreds of millions of dollars have been shipped.

Challenges include finding the right hardware to match Ukraine's needs. As a former member of the Soviet Union, its power system is not always compatible with other countries, including neighbours to the north.

The supply of generators cannot match demand, company officials said, especially as some of the most necessary deliveries can take months.

"Unfortunately, high-voltage transformers, which we need the most, are not there yet," Oleksandr Kharchenko, director at the Energy Industry Research Center based in Kyiv, said on Ukrainian state television on Wednesday.

He said there were a few in the world that could be shipped, but did not expect them to arrive before February at the earliest.