How long do children need to play on the merry-go-round to charge the lanterns?

When Empower Playgrounds, was started, we studied the amount of energy available from children at play.  We believe from research and observed experiments that a 10 to 12 year old child can output about 80-100 watts for about 20 minutes.  In order to make the playground equipment fun, we engineered the gearing and electronics to convert less than half of the input energy from children to electricity.  Typically about 30% depending on how fast they push.  The merry-go-round is not just a work wheel and it works well because more than one child is pushing while many more ride.  Typically 3 to 5 are pushing and as one gets tired, he or she jumps back on the riding deck and another child will jump off and push.  It is very interesting that the rpm stays almost constant as the children play, naturally taking turns pushing.  By the time you allow for generator efficiency, and small losses through the electronics, there is about 150 watts per hour being stored in the battery.  The range is about 100 to 200.  At school the children play 3-4 hours a day, so in total, the system makes about 500 watt-hours per day.  Not much energy, but enough to power about 50 LED lanterns, which we use in the rural African schools. The children do not need to play 3-4 hours a day to keep the battery charged. The need for the amount of play, directly relates to how many lanterns need to be charged that day, so the amount of power generated and used varies.


How much does a merry-go-round cost?

Cost Breakdown: 

Merry-Go-Round Equipment: $4700 USD

Lanterns (40): $1600 USD

Storage Battery, Electronic Wires, and Enclosure: $1100 USD

Solar Panel: $200

Shipping, Tax and Duty: $1800 USD

Installation and support: $600 USD

Total: $10,000 USD

Do you ship merry-go-rounds to other countries?

We have only installed one merry-go-round outside of Ghana, in Mali and that was in partnership with Empower Mali who funded the cost of the merry-go-round while we covered the cost of shipping and sending our experts to assist in the installation. The merry-go-round and generator are manufactured in the US by a professional playground company, PlayWorld Systems. We purchase 10 merry-go-rounds at a time and play to have the merry-go-rounds shipped to Ghana. It is easier logistically to send merry-go-rounds via truck to countries surrounding Ghana.

EPI simply does not have the funds to ship merry-go-rounds around the world at this time. If your organization is interested in a merry-go-round for your project outside of Ghana, EPI may be able to arrange the shipment to your country, however, you will need to cover the costs of the merry-go-round, the shipment, and have a person on the ground with an understanding of electrical engineering to assist with the installation. EPI suggests that organizations use the alternative of a solar powered system in lieu of a merry-go-round. We have set up schools with a solar powered system only in the past and have a great Lithium Ion battery pack that we can ship to your location. If you are interested in this, please contact us at and we can discuss what exactly you want to power (basic lights and fans or computers, and/or lanterns)


Do take requests to install merry-go-rounds at schools in Ghana?

Yes. However we only install our merry-go-rounds at schools and orphanages that need. The first thing we do is discuss the need of your community and your current access to power. We do not usually install our system at schools connected to the power grid. We can suggest and help you coordinate other solar alternatives if this is the case. The other factors we consider are the number of students at your school, the support of the community, and the distance from our current merry-go-round systems. When working with nonprofits prefer to split the cost of the merry-go-round and installation to help increase our impact.