Only one month into 2015, private equity firms, venture investors and development banks have poured $42 million into off-grid solar companies working in developing countries. That represents two-thirds of all off-grid investments closed in 2014.

The money was disbursed in four different rounds for companies in solar lighting, solar electronics charging and pay-as-you-go financing.

This week, Fidelity Growth Partners led a $10-million financing round for Greenlight Planet, a solar lighting company operating in Africa and India. Deutsche Bank and Global Partnerships also added to the round. 

Greenlight Planet sells mobile phone and solar lighting devices in order to help reduce expensive and dangerous kerosene use. The money will help Greenlight expand sales operations in Africa and grow its rooftop solar installation business. The company says it's on track to light 100 million off-grid households by the end of the decade.

Greenlight is also developing a pay-as-you-go mobile platform that will allow customers to pay for their solar lighting systems over weeks or months.  

Mobile payment platforms have become a catalyst for "beyond-the-grid" energy. By seeing themselves as energy service providers -- not just suppliers of a technology -- solar startups focused on energy access are gaining more attention from investors. That includes solar service providers like SolarCity and engineering giants like Schneider Electric.

"Beyond-the-grid enterprises are raising more and more money, but moving from social impact to real venture capital investment will require them to step up their game. That means providing seamless service levels to some of the most price-sensitive, difficult-to-reach customers on earth -- akin to what people in developed countries would expect," wrote Daniel Tomlinson in a GTM op-ed last month.

Days before Greenlight's round, the Kenyan mobile payment startup M-KOPA picked up $12.45 million in expansion capital from LGT Venture Philanthropy. This is the fourth time LGT has invested in M-KOPA, a leading pay-as-you-go platform provider that has 150,000 customers. The round also included former investors from the Lundin Foundation and Treehouse Investments, as well as a new investor, Blue Haven Initiative. 

The investment came just one month after M-KOPA secured $20 million in debt from the Commercial Bank of Africa.

Also this week, the International Financing Corporation, an arm of the World Bank, provided a $4.5 million loan to Off-Grid Electric, a Tanzanian solar lighting firm that picked up support from SolarCity last year. That helped the company close another $2.5 million from Cordiant Capital, a Canadian lender focused on emerging markets.

In late January, Greentech Media reported on a $12.6-million venture round for Fenix International, a company that sells and finances solar-powered battery systems designed for lighting, mobile phone charging and powering other electronics in the home. That round included some big names in energy and venture capital, including GDF Suez, Schneider Electric, Orange France Telecom, Tom Dinwoodie and Warner Philips.

Those three deals, closed within the first five weeks of the year, brought investment totals to just over $42 million. The early surge in financing is a sign that 2015 will be a strong year for leading companies in the off-grid solar and energy services sector.

Solar developers looking to connect with the grid are also anticipating a financial boost as well. The World Bank indicated this month that it will loan $500 million to India's Power Grid Corporation in order to build new transmission networks for photovoltaics projects worth 7 gigawatts of capacity.