Replacing fossil fuel based electricity?

BANGLADESH targets 10% electricity generation from renewable sources within 2021. To attain this target various fiscal and policy support initiatives have been offered. In 2003 the target was put forward by the government to install 50,000 solar home systems (SHS) within 5 years but the target was attained within 3 years. Already 3.5 million SHS have been installed in the country. Approximately 65,000 SHS were installed in the country every month. Alongside the remote hilly settlements and the isolated islands, SHS are now installed in areas where grid electric power supplements the power supply. People install SHS on rooftops and on support structures to avail the sunlight and convert it to useful electric energy to get light and energy in order to operate fans, TVs, irrigation pumps, mobile phone chargers, supply power to poultry farms, harvest crop, etc. In the isolated islands of Bangladesh, initiatives have been taken for developing at least 50 'mini-grids' based on solar energy to maximise the benefits of solar energy utilisation in the locality. The achievements of SHS are commendable and many people feel that solar (photovoltaic) energy and other renewable sources can and should replace our conventional power generation practices.

Increased use of renewable energy sources will help Bangladesh to not only fight global warming but also to support the initiatives for supplying electric energy to all. The country's electric energy generation system is dependent mainly on natural gas (almost 63%). Unfortunately, the conventional energy sources so far discovered in the country are limited and can no longer support the growing needs for power generation. The State Minister for Power, Energy and Mineral Resources recently informed that the government would not allow any new gas-fired baseload power project in the future as it is estimated that the supply shortage of natural gas could increase to 764 mmcfd in the period between 2015 and 2019.

On the contrary, increasing the share of renewable energy for power generation is neither cheap nor an easy target for technical management. The German experience is worth reviewing in this regard.

Germany has adopted an energy policy with the target to attain a nearly CO2 (greenhouse gas) emission free power supply system within 2050. Germany, the fourth largest economy of the world and one of the major advocates for 'green power' development, has built and secured technically stable and price affordable electricity supply systems. In December 2013, Germany had an installed power plant capacity of 186.8 GW (net) with a share of 19% wind, 19% photovoltaic (solar), 7% hydropower and biomass, 7% fuel oil and others, 15% natural gas, 7% nuclear and 26% coal based energy. Germany has been trying to transform its power supply systems from a conventional energy based generation to a system wwmainly relying on renewable energy. It updated its Renewable Energy Act in 2014 to provide guarantee to renewable energy producers with 'feed-in-tariffs' for 20 years after power plants' commissioning. The German legal instruments also ensured that power grid operators purchase the entire quantity for renewable electricity with priority. The power trade companies are to pass the deficit (difference between feed in tariff and market price) to customers by imposing a reallocation charge. As a result, power generation capacity from photovoltaics and wind energy has been increased within the last 5 years (between 2008 and 2014) from 10,846 MW to 29,828 MW. However the renewables' growth has come at a cost mainly for consumers. The subsidised renewable energy is developed and financed via a reallocation charge that is paid by the consumers. The reallocation charge has now reached a level twice as much as the wholesale price of electricity. Private customers in Germany pay more for electricity compared to private consumers in Japan and all other member countries of the European Union (except Denmark). Electricity prices in Germany are more than twice the OECD average and three times as high as in the United States (Source: Cornerstone Magazine).

Because of the unavoidable 'feed in intermittency' power system, managers in Germany continuously require balancing the renewable energy feed-in fluctuations for securing grid stability. The renewable power units significantly rely on the weather conditions including the strong and weak wind speeds and sunlight availability. The average cycle of wind and solar intensity can be predicted but it changes abruptly and has a significant impact on power generation capacity. Also, the power generation capacity dependent on renewable energy sources does not necessarily match with the peak demand hours. Therefore fossil fuel based power plants are intermittently operated between partial and full load operations. German power grid stability was attained at the cost of the conventional power plants. In other words, the difference between the consumption and rapidly fluctuating renewable energy supply has been met either by automatic switching on or switching off of the conventional fuel (coal, gas, oil) based power plants.

This is a major challenge for the grid operators but so far German operators have managed the balanced grid systems as they have efficient, smart grid management systems and highly flexible power plants. Germany has been continuing to take measures to upgrade its existing power plants (mainly those installed before the expansion of targets for wind and photovoltaic power plants) to allow greater flexibility. Surely it involves a lot of investment and efficient management to operate the flexible and smart grid based power system. Germany predicts that the role of fossil fuel based power generation will almost be the same in 2023 as it was in 2013. And in 2034 (when the planned renewable power generation capacity will increase to 173 GW), a conventional fuel based power generation capacity of 82 GW will still be needed (compared to 100 GW in 2012) to cover the demand and supply gaps (especially when wind speed will be low and sun shine will be weak or absent).

It is technically very challenging for Bangladesh (with a nearly 7,500MW power generation capacity) to accommodate huge flexibility in the grid system. A 400 MW power trip caused a countrywide black out for 10 hours last November. Such incidents demonstrate the state of our power system limitations. Also the primary energy balance for grid power generation (natural gas-62.39%, liquid petroleum (Furnace oil and diesel)-28.46%, coal-2.33%, hydropower-2.15% and import electricity-4.67%) so far has no share of renewable energy. If we intend to include and increase the power generated from renewable energy sources for the grid power, we should prepare our consumers for the increased cost for electricity and allocate huge resources for upgrading significantly flexible power systems. Also, the power system management efficiency needs to be improved many folds which in isolation is a fantasy to be materialised.

The writer is a mining engineer and writes on energy and environment issues.