Learning from GravityLight Users in Kenya

Introducing Part 2 of our blog series, sharing lessons learned from our GravityLight pilot in Kenya.

Testing, iterating, learning and improving has been a continual process throughout the development of GravityLight. From the start, we have also been committed to sharing these lessons learned with supporters, as well as the wider clean energy sector.

As a team, we are wholly committed to the highest standards of measurement, evaluation and learning. We recognise that GravityLight is an entirely new type of product and we want to be completely confident that:

a)    We are delivering a very high quality product that meets the needs of our users and delivers the intended impact outlined in our ‘theory of change.’

b)    We have a viable social enterprise business model that means we can deliver sustainable and scalable impact.

To achieve this, we have worked with external, independent partners to ensure that results from our research, from focus groups to longer in home observations, are as impartial, reliable and useful as possible.

Specifically, we conducted the following research:

  • Interviews (in person, phone and SMS) with potential customers and GravityLight users country-wide
  • Focus groups with potential customers and GravityLight users in Nyanza (rural households in the West of Kenya)
  • Home observations with GravityLight users in Nyanza
  • Instalment payment trials in Eastern, Western and Nyanza
  • 3 month in home trial comparing GravityLight and alternative solutions in Thika and Chavakali

This blog shares the key insights from across our research activities.

+ Local assembly learnings

Eager to make a positive impact across all facets of the GravityLight, we were keen to see if we could both produce and sell the GravityLight in Kenya, thereby helping create local livelihoods. Having reviewed the local manufacturing capability, we recognised early that GravityLight’s high tolerance mouldings could not be made in Kenya, however we were keen to test local assembly of GravityLight in partnership with Burn Manufacturing. This resulted in us importing components from China for assembly and packaging near Nairobi.

Whilst this approach creates local jobs and contributes to the economy, in our scenario, it added significant cost, complexity and time versus importing finished product from China.

  • Components are taxed at a higher rate than finished product
  • Potential VAT and duty exemptions, which solar solutions have, are currently only available for finished products
  • There is insufficient local manufacturing capability for GravityLight to reach the required ‘local value add’ to secure other tax breaks for locally manufactured products.

Tax regimes and manufacturing capability may change in future, and at scale; however in this scenario there is a clear trade-off and decision needed between prioritising cost for our core customer and beneficiaries, or seeking a wider social impact, at the risk of being uncompetitively expensive for our target market.

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+ There remains a huge need and demand for clean, safe and reliable off-grid lights

2 in 3 people in sub-Saharan Africa do not have access to electricity [World Bank 2014: 63%]

GOGLA’s latest industry report details how, despite the significant increase in the number and scale of the solar market, and electrification initiatives, over the past 10 years “the size of the potential market, in terms of people to be served, has remained largely unchanged.”


  • Unreliable power: frequent powercuts and intermittent power mean that clean, safe and affordable off-grid lights are still needed by those connected to the grid
  • Population Growth: is faster than electrification rates in sub-Saharan Africa
  • Product lifespan: meaning people with solar solutions need to replace them every 1-5 years

+ Rapid growth of the solar industry

Across the past 5 years there has been a huge growth in number and range of different solar solutions – from small, pico lanterns to multi-light home systems able to power TVs and fridges. This growth, in both solar manufacturers and distributers has been particularly concentrated in East Africa, and particularly Kenya. For example, driven by it’s strong mobile money ecosystem, 86% of the ‘Pay-As-You-Go’ solar market is in East Africa. [GOGLA]

Most importantly, the quality and performance of solar products has increased, whilst their prices have decreased.

Looking back to the inception of GravityLight it was the high cost of the PV panel and battery that the founding GravityLight team were seeking to avoid by creating a solution that eliminated these – creating live power with the lift of a weight instead. The graph below shows the substantial cost reductions of these components across the past 5 years.

  Over the past 5 years the quality and performance of solar solutions has increased whilst prices of key components have decreased significantly.    [GOGLA and Dalberg's  2018 Solar Market Trends report ]

Over the past 5 years the quality and performance of solar solutions has increased whilst prices of key components have decreased significantly.

[GOGLA and Dalberg's 2018 Solar Market Trends report]

User feedback on GravityLight: what they liked and what improvements they wanted

Below are some of the key insights that emerged from the multiple external evaluations we conducted on GL02 during the Kenya pilot:

Money Saving:
96% of GravityLight users reported savings as they reduced their use of and spend on kerosene (Phone interviews of 94 customers)

No smoke or flames:
70% of GravityLight users reported a health benefit.

Spending time with families without access to electricity or with intermittent power, helped us go beyond the statistics to understand what these challenges meant on an individual level and what people expect and value from alternatives, such as GravityLight.

+ What users needed: Brighter lights for longer!

GravityLight’s 15 lumens is not only brighter than a kerosene lamp but is also safer, better for the environment and saves families money over time.

However, users understandably wanted more - brighter lights to be able to light up more of their homes, especially in larger, rural homes.

They also wanted a longer lasting light. Although users were open and willing to manually power their lights, having to lift up the weight every 20 minutes became tedious over time.

Crucially, uptake of GravityLights at the end of the testing period by users, was significantly less than for the solar products, with brightness and duration as the main reasons for this.

+ What users wanted: mobile charging

The Communications Authority of Kenya reports that over 90% of the country’s population owns a mobile phone. As well as connecting with friends and conducting work by phone, mobile money (eg. MPESA) has revolutionised how even the most remote and low income households can pay, receive and save money.

Given this huge growth in use and benefits of mobile phones, and the cost and difficulty of recharging them, mobile charging was top of the list of additional features desired by users.

+ What users wanted: ability to pay in small instalments

In the words of our sales agents:

“Many of our customers are earning $2-4/day, through their own business ventures such as selling fruit and vegetables or as day labourers. They cannot afford to pay $25 at once but are keen to spread it out into small payments over time. As people save money on kerosene, they are able to put these savings towards their instalment payments instead.”

On consultation with our sales team and prospective customers, we tested a repayment scheme of $10 deposit and weekly payments of $1.50 – with the ability for customers to over pay or pay more frequently, when the harvests are good for example.

To reduce the risk of default, we worked with local community and savings groups, which acted as character references and social support to encourage repayment.

+ What the sales team wanted: a technical ‘Pay to Own’ solution

Regular follow up is essential to ensure instalment payments are made - we used SMS and phone call payment reminders however people preferred to pay in person. Given how remote our customers were, regular in person visits are an unsustainable model.

A longer term, sustainable solution would require a more automated system of reminders, as well as a technical solution where the product would stop working until the next instalment payment is made.

Our upcoming final blog in this series shares the conclusions we’ve drawn from these insights and what that means for the future.