Blog post from the International Institute for Environment and Development. As developing countries transition towards low carbon economies, governments must take difficult decisions about how they should scale up their renewable energy sectors. Initiatives, such as the Scaling-up Renewable Energy Programme (SREP), aim to catalyse investments in renewables, often with outside support from the private sector. But they face tough choices between investing in proven or novel low-carbon technologies, and between large-scale and small-scale approaches.