Mitigation of peak loads with solar energy in an enterprise

The electricity consumption in enterprises has a significant share in the overall energy consumption. One of the main changes for the electricity consumers in Estonia has been the hourly-based billing that for larger electricity consumers (usually industries) was implemented from April 2010. What is more, these consumers usually have to make contracts with power companies with specific conditions. One of the conditions usually applied is, that the larger electricity consumers have a consumption-based threshold: when the energy consumption in a single hour exceeds a certain limit, a higher price has to be paid for the electricity consumed over the before mentioned limit. This above-normal demand from the electrical grid during a short period of time can also be described as a peak load. In the current paper renewable electricity that would be generated on-site using PV-panels is considered for the mitigation of these peak loads in enterprises. An enterprise that is located in a rural area in Central-Estonia and is connected to the main Estonian Electricity Network Operator was chosen as an example case for the analysis. The simulated renewable energy system is connected to the grid and therefore has no need for storage equipmentVytauto Didžiojo universitetasŽemės ūkio akademij

Increasing self electricity consumption by using double water heating tanks for residential net zero-energy buildings

The article concentrates on the energy storage problem arising from small scale residential electricity generation, in the current case wind micro turbine and PV panels. The research objective is to increase the locally consumed energy share by using two water tanks, aiming to shorten the breakeven periods of the renewable energy production devices. The shaved peaks from stochastic wind turbine and PV generation are fed into a preheating tank; the remaining excess power is fed into the main tank. The produced and consumed energies are in balance. The observed time period was one year with averaging time step 5 minutes. The annual PV/wind energy production share is assumed to be 30 %70% in favor of the wind. The anticipated result is to increase the renewable energy supply cover factor from 0.43 with a single heating tank up to 0.60 by deploying two tanks. If the same production peak shaving principles under the same conditions are applied seasonally, then the resulting supply cover factor can be augmented up to 0.69Vytauto Didžiojo universitetasŽemės ūkio akademij