The agency has been appointed on a seven-month contract to develop a new PR strategy and implement a targeted media relations campaign.
UKPR generates power to enable the National Grid’s balancing services and has 14 power generation facilities across the UK.
The company chose Aspectus because of its industry knowledge and strong relationships with key journalists.
UKPR CEO Tim Emrich said: "The team has great market knowledge and really understands the type of impact we want to have. We are confident it knows the best way to communicate our message to the people that matter."
Kate Garratt, head of energy at Aspectus PR, said: "Flexible power generation ensures the security of energy supply to households and businesses across the UK, and is of increasing importance as the nation sets its balancing strategy for the coming decades.
"We know we can develop an excellent strategy that positions it well in the market at this important juncture in the capacity market debate."