The EU funded PUMP-HEAT project (Performance Untapped Modulation for Power and Heat via Energy Accumulation Technologies) was kicked off in September. The objective of the project is to increase the flexibility of the Combined Cycle power plants and the operation of gas turbines. We interviewed the project coordinator Alberto Traverso, Professor of Energy Systems at University of Genoa, who leads the consortium consisting of 14 participants from 8 countries.
Natural gas fired Combined Cycle (CC) power plants are currently the backbone of EU electrical grid, providing
most of regulation services necessary to increase the share of non-programmable renewable sources into the electrical
grid. As a consequence, Original Equipment Manufacturers (OEMs) and Utilities are investigating new strategies and
technologies for power flexibility. Current research activities for CCs flexibility enhacement (e.g. power ramp augmentation, Minimum Electrical Load - MEL - reduction)
focus mainly on the GT and extend the operational envelop of this component, which is primarily constrained by emissions
(typically, CO at low load and NOx formation at full load).
On the other hand, existing cogenerative CCs are usually constrained by thermal user demand, hence can provide limited services to the grid.
At the same time, CHP plants are highly promoted for their high rate of energy efficiency (> 90%) and combined with district heating network are a pillar of the EU energy strategy.
PUMP-HEAT aims at an innovative approach to enhance CC flexibility through bottoming cycle innovations, applicable also to cogenerative CCs.
PUMP-HEAT proposes a solution that enables synergies between different energy networks, in order to provide more flexibility, more resilience and to allow a larger penetration of variable renewables.
Gas fired power plants will be affected by a slower retirement rate in terms of capacity (12%) compared with other types of power plants, therefore innovative solutions are needed in the already existing power plants to face the challenges of the current and future electrical markets. New investments and plants are foreseen particularly in Eastern Europe where the turn-over of such plants is already ongoing. New investments and plans are also expected to cover the doubling of gas fired generation expected within 2035. According to all these issues, the foreseen NG based power capacity in 2030 will be around 230 GW starting from the current capacity of 191 GW.
To un-tap the unexploited reserve of flexibility in cogenerative CCs, and to further enhance turn-down ratio and power ramp capabilities of power oriented CCs,
PUMP-HEAT project proposes the demonstration of an innovative concept based on the coupling of a fast-cycling highly efficient heat pump (HP) with CCs.
The integrated system features thermal storage and advanced control concept for smart scheduling.
In the PUMP-HEAT integrated concept, the following advantages are obtained:
- the HP is controlled to modulate power in order to cope with the CC primary reserve market constraints;
- the high temperature heat can be exploited in the district heating network, when available; low temperature cooling
power can be used for gas turbine inlet cooling or for steam condenser cooling, thus reducing the water consumption;
- in both options, the original CC operational envelope is significantly expanded and additional power flexibility is achieved.
- the HP will include an innovative expander to increase the overall efficiency.
In general, the CC integration with a HP and a cold/hot thermal storage brings to a reduction of the MEL and to an increase in power ramp rates, while enabling power augmentation at full load
and increasing electrical grid resilience and flexibility.
The PUMP-HEAT concept could stop the mothballing of EU Combined Cycles, pushing new installations and the retrofitting of already existing power plants giving a second chance to such these crucial energy systems in the current and future energy scenario.
The PUMP-HEAT technology will be able also to have technological impacts on the CC and GT power plants increasing the annual and seasonal efficiency up to 5%, reducing OPEX of 3%, increasing the possibility for such plants to sell more electricity on the Regulation and Ancillary Services Electrical Market, thanks to their increased flexibility and fast responsivity (about a 30% of the generation could be sold on these markets at a 50% higher revenue) and reducing the number of start-ups of 5-10% and the related extra costs, equivalent operating hours (EOH) and wear.
The PUMP-HEAT Combined Cycle aims to become a new paradigma for GT and CC power plants recognized in both the technical and academic panoramas.