It's a while away but for the astute planners it is worth thinking about six months out. The Christmas season is a time of celebration and festival in multiple cultures around the world and although many cultures celebrate differently, some items are transferable, especially fairy lights and energy savings.

Lotte, one of Korea's leading department stores always hosts marvelous Christmas tree displays in its Uljiro branch. Lotte, in 2007, used 2 million lightbulbs in front entrances and walkways for their Christmas festival. In 2007 this cost KRW 9 billion. Though we are not picking on Lotte as in 2008, reportedly, Lotte Hotel bought some outdoor LED Christmas decorations. Korea IT Times simply notices their display as the largest and perhaps most noteworthy in Korea which is a compliment.
Novice party planners, Korea IT Times thinks that a UK based company called Green Grape Technology could assist Lotte with their solar LED Christmas/Fairy lights. They sell 96 LED lights for 49 UK pounds each. For 2 million LED lights it would cost just over 1 million GBP, roughly KRW 1.8 billion.
The 2007 festival started on November the 10th. Let's say for the sake of calculations that the festival ran until 10th January, that's about 60 days * 10 hours (approx.) of twilight. = 600 hours of light. This is a significant amount of lighting and with Korean media suggesting power outages due to shortages we wonder both what will become of these marvelous displays and if public opinion about them will change.
Irrespective, an investment of KRW1.8 billion, which may not be the cheapest available solution, will, according to some reports, save 1/10th in power. But how much is that
After many additional calculations, the energy calculator at Christmas Lights and Decorations says that for 2 million Christmas/Fairy lights 8,000 KWH are used at an approximate cost of USD22,400 per day. All things going to plan, for 60 days this is an immediate savings of just over USD1.3 million because Green Grape technology's lights are solar.
So, all in approximate costs gleaned from approximate sources, if Lotte comes up with KRW 1.8 Billion for 2 million Solar LED fairy lights, they save approximately KRW 1.6 Billion in the first 60 days and the lights might be able to be used the next year.
That's astute planning! We just hope that there is a solar LED fairy light manufacturer that has developed a Smartgrid (yes this is where the 'Green' batteries come in) for festival lighting displays.
*our approx. calculations of money back in just over 60 days do not include batteries, manpower or additional considerations, further, the currency conversions were from web based non standards sources.