CASE

The Pulp & Paper is one of the most energy-intensive sector with average energy costs ranging from 16 up to 30 % of total cost structure. With high electricity and heat consumptions, pulp and paper plants are particularly well-suited for combined heat and power (CHP) units. Furthermore, integrated pulp and paper plants can leverage by-products of pulp-making process as input fuel for the cogeneration. In Europe, the industry produces on average about 46 % of the electricity it consumes.

This case is considering an integrated Pulp and Paper plant with electricity demand over 1000 GWh and steam demand over 4 millions tons, which translates in energy costs close to 30% of the production costs. The CHP unit is using bark and black liquor resulting from pulp production together with fuel and covers almost 90 % of electricity demand and 100% of steam demand. The remaining need for electricity is purchased on electricity markets. Electricity can also be sold on the market when the CHP unit output exceeds the electricity demand of the plant.

The energy structure of such integrated Pulp & Paper mill can be summarized as follows:

Challenge

With the liberalisation of the electricity markets and the increase of the renewable energy sources in the energy mix, large industrial sites are facing more and more volatile electricity prices. This apparent threat can also be seen as an opportunity if energy flexibilities are leveraged optimally based on electricity prices. The CHP units in pulp & paper mills offers particularly interesting opportunities for leveraging energy flexibility. By-products can be stored to be used at optimal moment, pressure reducing valves (PRV) can be preferred to steam turbine in the periods of very low electricity price and extra steam and electricity can be produced in periods with high electricity price. These flexibility levers on the electricity generation can also be combined with flexibility on electricity consumption by shedding, shifting or rescheduling loads. The main challenge is to leverage this complex and interrelated system of flexibility levers in an optimal way based on volatile electricity prices.

Solution

N-SIDE ENERTOP solution uses the latest predictive and prescriptives analytics techniques to convert energy flexibilities into tangible gains on the energy bill. Based on an accurate electricity price forecast for the next few days, ENERTOP optimizes both the production scheduling and the CHP unit planning in order to consume and produce electricity at optimal moment and allow maximum value to be captured from reserve markets. This optimization takes into account market, technical and human resources constraints and leads to recommendation implementable in practice. In our particular case, it helps to reach up to 15% saving in energy costs (i.e. more than EUR 2.5 M per year) by leveraging the following flexibility drivers in an optimal way.
ENERTOP has a user friendly interface which enables visualizing the different component of the optimal energy strategy, the forecast on electricity price and your optimized energy cost.