The Council on Energy, Environment and Water (CEEW) experts navigate India's $100bn renewables challenge to present a view on a much-needed boom in this crucial sector. India's solar power capacity has grown nearly 400 times in six years, from a mere 17.8MW in March 2010 to nearly 6,998MW in April 2016. However, the real solar boom is yet to come, as India strives to realise its ambitious target of 100GW of installed solar PV capacity by 2022. The five-fold jump from the Solar Mission's original target of 20GW under-scores the present government's commitment to making renewable energy (particularly solar) a central plank of India's energy sector modernisation. Combined with initiatives such as 'Make in India' and 'Skill India', the targets aim to give impetus to solar developers and manufacturers and transform the investment landscape. The Council on Energy, Environment and Water (CEEW) calculated that $100 billion would be needed as capital investment. This assumes a rapid fall in both module prices (30 per cent by 2021-22) and balance of system costs, along with moderate inflation (6.5 per cent). Less benign inflationary conditions and moderate declines in system costs would add another $13 billion to the bill. In 2015, global investment in renewable energy (excluding large hydro) was $285 billion, adding 134 GW. A majority ($160 billion) was directed toward solar PV projects (56GW). Against this, India's total investment in renewable energy was $10.2 billion (22 per cent higher than in 2014), with utility-scale solar projects accounting for $4.6 billion. Overseas finance was critical: as of July 2015, more than half of India's large grid-connected renewable energy projects had some share of international funding. The government hopes that 7.2GW of grid-scale solar PV capacity would be added in the financial year ending March 2017. An additional 4.8GW of rooftop solar capacity is being targeted. Adding 12GW of PV capacity would require about $15 billion (the cost of rooftop systems is higher than utility-scale power plants), more than three times India's investment in solar PV in 2015. These are substantial investment needs. In Q4 of 2015-16 RE investments in India reached $1.9 billion, up only 6 per cent from the comparable period in 2015. To be sure, global investments in renewable energy fell 12 per cent during the same period due to the slowdown in other emerging economies. Nevertheless, on this trajectory, the investments will fall well short of the 2022 targets. This limited flow of investment could be attributed, at least in part, to the risks that investors perceive for solar projects in India. Prime among these is the poor financial health of many state electricity utilities. The government has launched the Ujjwal Discom Assurance Yojna (UDAY) to transfer the liabilities of the utilities to the balance sheets of state governments, conditional on improved operational efficiency and with provisions for quarterly tariff increments to offset the rise in fuel prices. But it will take at least two years before UDAY can be declared (at least partially) a success or a failure. Notwithstanding these challenges, India is opening new routes to channel foreign investment into renewable energy. One opportunity is via the India-led International Solar Alliance (ISA). ISA offers a significant opportunity for solar-rich countries to increase access to additional and lower-cost finance. In collaboration with the private sector and institutional investors, ISA could facilitate the flow of $1 trillion into solar projects in member countries. India's role in the New Development Bank is another opportunity to shift a substantial proportion of the loan portfolio to solar/RE projects. Finally, there are new initiatives for payment security for grid-connected projects, and to de-risk and mobilise $1.4 billion for decentralised energy projects. India's solar sector is now awaiting big investments. Kanika Chawla is Senior Programme Lead and Dr Arunabha Ghosh is CEO, Council on Energy, Environment and Water (http://ceew.in), one of South Asia's leading independent think-tanks. Dr Ghosh is, most recently, co-authored 'Energizing India: Towards a Resilient and Equitable Energy System'.