Hello everyone.

I am working on a project relating renewable energy consumption to health outcomes in Nigeria.

My model contains 4 variables, 3 of which are I(1) variables, and the last one an I(2) variable. The I(2) variable is Life expectancy at birth (for Nigeria), and it is my dependent variable. Others are renewable energy consumption per capita, GNI per capita, and CO2 emissions (in metric tons per capita), all for Nigeria.

Is cointegration possible? If yes, which technique exactly? Do I have to find a proxy for life expectancy?

Thanks for anticipated responses.